ROSE-MARY SARGENT- Scientific Experiment and Legal Expertise

ROSE-MARY SARGENT*

SCIENTIFIC EXPERIMENT AND LEGAL EXPERTISE: THE WAY OF EXPERIENCE IN

SEVENTEENTH-CENTURY ENGLAND I. Introduction

EARLY EXPERIMENTALMS, because they stressed that experience was to be the foundation for a new way of doing science, are often characterized as advocating an empiricist epistemology. Traditionally, empiricists have maintained that all knowledge is to be grounded in sense perception and that science is to be restricted to the knowledge of actual and observable phenomena. As a consequence, they have rejected the idea that we can ever determine the truth of theories that seek to explain regularities in terms of unobservable entities and processes. Given this definition, however, a problem of historical interpretation immediately arises because it is not clear that early English advocates of experimentation, particularly Francis Bacon and Robert Boyle, lived up to this empirical ideal in their actual practice.2 For this reason, a number of studies have been produced in an attempt to account for their frequent appeals to experience while also taking account of the actual theoretical leaps made by both. For example, it has been seen as an inconsistency in Boyles work that, while he advocated experimentation, he also spoke of corpuscularianism as the true philosophy.3

*Department of Philosophy, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A.

Received 10 December 1987; in revised form 6 June 1988. Empiricism is a term that tends to be used rather loosely. But historically, from ancient times

to the present, empiricism has normally been identified with the position that knowledge claims must be restricted to the actual and the observable. See, e.g., G. E. R. Lloyd, Science, Folklore and Ideology (Cambridge: Cambridge University Press, 1983), for an account of empiricism in the ancient medical sects; Richard H. Popkin. The History of Skepticism from Erasmus to Spinoza (Berkeley: University of California Press, 1979). fdr an acciunt of ihe empiricism of Gassendi and Mersenne; and Bas van Fraassen, The Scientific Imane (Oxford: Clarendon Press. 1980), for the latest contribution to empiricist science. Ske JosephJ. Kockelmans, On the Problem of Truth in the Sciences, Proceedings and Addresses of the American Philosophical Association 61 (1987). 5-26, for the most recent criticism of empiricist assumptions.

Van Fraassen, The Scientific Image, pp. l-2, e.g.. characterizes Boyle as a failed empiricist because he advocated a corpuscular explanation of the macroworld.

A number of writers have seen Boyles advocacy of corpuscular explanation as indicative of non-Baconian influences on his thought, despite the fact that Bacon also stressed the importance of investigations into the latent configurations and process of bodies which for the most part escape the sense. [The New Organon, Bk. 2, aph. vi-viii, in: The Works of Francis Bacon, James Spedding, et al. (eds), vol. VIII. (Cambridge: Riverside Press, 1863), pp. 173-1771. See,

Stud. Hist. Phil. Sci., Vol. 20, No. 1, pp. 19-45. 1989. Printed in Great Britain.

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0039-3681/89 $3.00 + 0.00 @ 1989. Pergamon Press plc.

20 Studies in History and Philosophy of Science

The idea that there are contrary tendencies in the philosophy of Bacon and

Boyle arises from the widespread practice of placing an empiricist gloss on

their appeals to experience. But, if their notion of experience is not that of

standard empiricism, then their goal of discovering the hidden causes

operative in nature need not betray an inconsistency. In the following it will

be argued that their use of legal analogies provides a good reason for rejecting

an empiricist interpretation of their appeal to experience.s

The legal overtones of the early experimentalists language, the references

to trials, and witnesses, and testimony, are hard to ignore, but the significance

of these locutions for the rise of experimental science has yet to be fully

appreciated. Some previous studies have focused upon the analogy between

the notion of law in the two realms. These analyses have proven

unsatisfactory, however, because the analogy does not appear to be used in

this substantive sense. Boyle, for example, maintained that law, in the

e.g., Larry L.audan, The Clock Metaphor and Hypotheses: The Impact of Descartes on English Methodological Thought, in: Science and Hypothesis: Historical Essays on Scientific Methodology (Dordrecht: D. Reidel. 1981); and Robert Hugh Kargon, Walter Charleton, Robert Boyle and the Acceptance of Epicurean Atomism in England, Isis 55 (1964), 184-192. While Boyles eclecticism led him to borrow different elements from a number of natural philosophers, who could all be said to have therefore influenced him, the fact that he was not a strict empiricist does not entail that he was not an advocate of Baconian methodology. For the non-empiricist elements in Bacons thought, see: Mary Hesse. Francis Bacon, in A Critical History of Western Philosophy, D. J. OConnor (ed.) (New York: The Free Press, 1964), pp. 141-152; Mary Horton, In Defence of Francis Bacon, Studies in History and Philosophy of Science 4 (1973), 241-278; Lisa Jardine. Francis Bacon: Discovery and the Art of Discourse (Cambridge: Cambridge University Press. 1974); David Oldroyd, The Arch of Knowledge (London: Methuen, 1986). pp. 6C-63; and Peter Urbach, Francis Bacons Philosophy of Science (LaSalle, IL: Open Court. 1987). See Peter Alexander, Ideas. Qualities and Corpuscles: Locke und Boyle on the External World (Cambridge University Press, 1985); and Rose-Mary Sargent, Robert Boyles Baconian Inheritance: A Response to Laudans Cartesian Thesis, Studies in History and Philosophy of Science 17 (1986). 469486, for discussions of the Baconian elements in Boyles philosophy.

Even when the non-empirical elements are recognized. as in the accounts cited above, the references to experience are still taken as indicative of an empiricist tendency to which the non- empirical must be reconciled.

The legal tradition is only one of a number of traditions that need to be examined for a clearer understanding of Boyles experimentalism. The theological tradition, for example, was also an important source for a broad notion of experience. See Barbara Shapiro, Probability and Certainty in Seventeenth-Century England (Princeton: Princeton University Press, 1983); and Henry G. van Leeuwen, The Problem of Certainty in English Thought: 1630-1690 (the Hague: Martinus Nijhoff, 1963).

See Paul H. Kocher, Francis Bacon on the Science of Jurisprudence, Journal ofthe History of Ideas 18 (1957), 3-25; and Bernard McCabe, Francis Bacon and the Natural Law Tradition, Natural Law Forum 9 (1962). 111-121. The attempt to interpret law univocally creates confusion. McCabe, for example, finds it puzzling that Bacon was apparently unconcerned with natural law in the legal tradition since he was concerned with the existence of ascertainable natural laws in the cosmological sense. (p. 111.) But for Bacon natural laws in science are to be discovered from particulars, whereas natural laws in the legal sense are the rational first principles discoverable from and grounded upon individual reason. Therefore, it is not surprising that Bacon was opposed to natural laws in the legal sense, just as he appears to be in McCabes analysis.

Scientific Experiment and Legal Expertise 21

scientific sense, should be understood metaphorically. Also, Jane Ruby has recently argued that the notion of a scientific law had its roots in the discipline of mathematics, not in the legal tradition. s The question remains then, what was the significance and force of the legal analogy? What role did it play in experimental discourses?

Most often, the analogy appears in methodological contexts. Experimenta- tion is said to be the method by which nature is put on trial and made to reveal its hidden workings. Since the analogy appears to be used in order to clarify the methodological dictates of the experimental philosophy, it is reasonable to suppose that an understanding of the procedures employed by the legal profession in 17th-century England could provide an insight into the methodology of experiment. The aim of this study is not to provide an exhaustive historical account of the rise of the experimental ideal. An examination of the arguments put forward by the lawyers for the justification of their procedures, however, ought to shed light on the experimentalists attempts to justify the superiority of their techniques over traditional empiricist and rationalist approaches to the study of nature - in particular, on their epistemological justification of experience as the foundation of the new science. 10

Boyle, in his A Free Inquiry into the Received Notion of Nature, vol. V, pp. 170-71, notes that because inanimate things lack intelligence, they cannot, strictly speaking, make their motions conformable to laws. [This, and all future references to Boyle, are taken from The Works of the Honourable Robert Boyle, 6 vols., Thomas Birch (ed.) (Hildesheim: Georg Olms, 1965 fats. edn of 1772 London edn)]. Chief Justice Matthew Hale also drew a distinction between laws of nature which were fixed and unalterable and laws of men which were not. See, Matthew Hale, Considerations Touching Amendments or Alterations of Laws, printed in: Edmund Heward, Matthew Hale (London: Robert Hale, 1972). Bv the 18th centurv these distinctions became blurred, however. Blackstone, for example, stated that a law signcfies a rule of action and it is applied indiscriminately to all kinds of action whether animate, or inanimate, rational or irrational. See William Blackstone, Commentaries on the Laws of England, vol. I (Chicago: University of Chicago Press, 1979 fats. edn of 1765 edn), p. 38.

Jane E. Ruby, The Origins of Scientific Law, Journal of the History of Ideas 41 (1986). 341-360.

Boyle, for example, spoke of the testimony of nature and said that matters of fact ought to be brought to trial in his Hydrostatical Paradoxes, vol. II, pp. 742,744; and spoke of judicious and illustrious witnesses in his New Experiments Physico-Mechanical, vol. I, p. 34. Bacon spoke of the inquisition of things in The New Organon, Preface, in The Works, vol. VIII, p. 35; and noted that nature exhibits herself more clearly under the trials and vexations of art than when left to herself in De Dig&ate et Augmentis Scientiarum, Bk. 2, ch. 2, in The Works, vol. VIII, p. 41.5.

Shapiro, Probability and Certainty, in her examination of law and science in the 17th century, has shown an important link between the two realms in their shared notion of moral certainty. However, she does not provide a detailed discussion of the notion of experience which was the ground for this type of certainty. Neal Gilbert, Renaissance Concepts of Method (NY: Columbia University Press, 1960), discusses the relevance of legal methodology for English science, but he restricts his attention to the type of law taught at the universities and not that which was practiced by common lawyers such as Bacon at the Inns of Court. This is not the onlv time that legal practices have had an-important influence on science. See G. E. R. Lloyd, Magic, Reason and Experience (Cambridge: Cambridge University Press, 1979). Lloyd maintains that the legal system of the polis of ancient Greece was important for the rise of science per se.


The examination of the relations between science and other areas of the

culture of a particular historical society has been, for the most part, a task

carried on by sociologists of science. While the following analysis shares some

similarities with sociological approaches to the history of science, my main

purpose is to examine this external area for elucidation of the concepts

employed in scientific argument. If, for example, one finds that a more

familiar cultural factor has been used to help explain an innovative idea in

another area, it is likely that an understanding of the cultural illustration will

lead to a better understanding of the idea being illustrated. The first part of

this paper will examine the specifically epistemological aspects of the

arguments put forward by English lawyers in defense of the practice of

common law. This discussion will be followed by an analysis of how

Boyle used these arguments as part of his justification of experimental

science. In a concluding section it will be argued that the failure to appreciate

the significance of the legal analogy has led to serious misunderstandings of

the epistemological foundation of Boyles experimental science. In particular,

the recent sociological analysis by Steven Shapin and Simon Schaffer,

Leviuthan and the Air-Pump, will be criticized for its oversimplification of the

Analogously, the legal tradition could be seen as important for the acceptance of experimental science in England; but my aim is not so much to provide a historical explanation for the rise of the experimental ideal, as to investigate how the experimental ideal was justified by reference to the tradition.

There is controversy within the sociology of science about the proper methods and aims of sociological analysis. See the exchange in Social Studies of Science 12 (1982) between Thomas F. Gieryn, RelativisUConstructivist Programmes in the Sociology of Science, pp. 227-297; H. M. Collins, Knowledge, Norms and Rules in the Sociology of Science. pp. 229-309; Michael Mulkay and G. Nigel Gilbert. What is the Ultimate Question?, pp. 309-319; and Karin D. Knorr-Cetina. The Constructivist Programme in the Sociology of Science: Retreats or Advances?, pp. 32&324. Historians of ideas have tended to shy away from social analyses because they do not share some of the normative conclusions traditionally associated with the sociology of science. But, the incursion of social factors into scientific discourse need not entail radical theses about the arbitrary nature of knowledge. In the following my analysis will be closer to a comparative study of the corresponding communities in other fields, suggested by Thomas S. Kuhn, The Sfrucrure of Scientifi:c Revolu/ions, 2nd edn (Chicago: Chicago University Press, 1970), p. 209. There are many ways in which social factors may influence science. I agree with Delamonts evaluation of the work done in the sociology of science to date, that it has failed to compare and contrast science with other bodies of knowledge and members of other occupational groups. See Sarah Delamont. Three Blind Spots? A Comment on the Sociology of Science by a Puzzled Outsider, Social Studies of Science 17 (1987). 163-170. p. 165.

The common law is that which was practiced by Bacon and that which was most familiar to educated Englishmen. That is. while the content of the law itself was extremely complex and only someone educated at the Inns of Court would understand these intricacies, the procedures. e.g. of precedent and jury trial, were well known. Blackstone, in his Commenturies [vol. I, p. 71. cited Lockes claim that it would be a strange absurdity to suppose that gentlemen of independent estates and fortune would be ignorant of the law. For Boyles dealings with the law see R. E. W. Maddison, The Life of the Honourable Robert Boyle (New York: Barnes and Noble, 1969). Since the legal analogy is methodological and not substantive, acquaintance with legal procedures is sufficient for my purposes.


issues with which the experimentalists and the lawyers of 17th-century England were concerned. l3

II. English Common Law

The tradition of common law differed in a number of ways from that of Roman law, as practiced on the Continent. Most importantly, the traditions were based upon radically different foundations. Roman law took the Code of Justinian as its model. It consisted of a dialectically constructed and codified body of legal doctrine based upon rational first principles and the citation of authorities, and often concerned itself with such academic exercises as the question of the validity of Lazaruss will after he had been brought back to life by the hand of Christ. I4 Common law, on the other hand, was not a uniform system capable of codification. As precedent law, it largely consisted of chronological collections of past cases in the Yearbooks and Register of Writs. Because this lack of system could make learning and practice difficult, lawyers and students found it convenient to make abridgments of past cases listing them under various headings for easy reference. The lack of system in the common law, while inconvenient, was not viewed as a weakness, but as part of its strength because it meant that the law would be flexible enough to allow for expansion to meet new needs and modification to accommodate unusual cases.

%teven Shapin and Simon Schaffer, Leviafhan and the Air-Pump (Princeton: Princeton University Press, 1985).

The details of this discussion are taken from J. H. Baker, An fnfroducfion fo English Lega/ Hisfory (Loadon: Butterworths. 1971); Baker, The Reports of John Spelmun, 2 vols (London: Seldon Society, 1978), vol. II; Harold J. Berman, Law and Revolufiont The Formation of fhe Western Legal Tradition (Cambridge: Harvard University Press, 1983); Willinm Holdsworfh, A Hisfory of English Luw, 12 vols, 4th edn (London: Methuen, 1936); E. W. Ives, The Common Lawyers of Pre-Reformufion England (Cambridge: Cambridge University Press. 1983); John H. Langbein, Presecufing Crime in the Renuissunce (Cambridge: Harvard University Press, 1974); Brian P. Levack, The Civil Lawyers in England (Oxford: The Clarendon Press, 1973); Wilfred R. Prest, The Inns of Courf under Elizabefh I and the Early Sfuarfs: 159&1640 (NJ: Roman and Littlefield, 1972); and W. C. Richardson, A History of the Inns of Courf (Baton Rouge: University of Louisiana Press, 1975). Roman law was taught at English universities for use in the courts of the Admiralty and the Church. Common law was used for all other legal matters, and was taught at the Inns of Court.

l5The foundation of the law was considered to reside in the Writs, which were arranged in groups within the Register: and the Yearbooks which were records of past cases said to yield a continuity of experience. (Ives, The Common Lawyers, p. 160.) Baker, Reporfs of Spelmun, vol. II, pp. 27-28, argues that there was not, in fact, as much continuity as the lawyers claimed, but the issue here is how the lawyers justified their procedures. not whether this justification was completely warranted.

Bacon and Hale both argued for more system in the common law. Bacon. in his Maxims offhe Law. Epistle Dedicatorv, in The Works. vol. XIV, p. 175, wanted to reduce the laws to more brevity and certainty by compiling digests (cf. Holdsworths discussion, Hisfory of Engksh Luw, vol. V, pp. 485-487). Hale in his Considerafions Touchina Amendments. in Heward. Muffhew Hale. p.l64, wanted one large and authentical abridgement of the Books and Tracts of the law reduced under apt and alphabetical titles. For the flexibility of the lawyers approach to precedent, see Ives, The Common Lawyers, p. 156; Baker, Reports on Spelman. vol. II. p. 163; and Holdsworth, A Hisfory of English Law, vol. IV, p. 285.


Flexibility was not the sole concern, however. The common lawyers also maintained that their practice was able to yield a greater degree of certainty than the Roman one - a certainty that was based upon a vast amount of experience. Early in the 17th century, Sir Edward Coke maintained that Roman law was less certain than common law because it depended upon a number of interpretations and glosses that gave rise to so many diversities of opinions, as they do rather increase than resolve doubts and un- certainties.16 In contrast, common law was based upon:

the resolutions of Judges in Courts of Justice . reported in our books, or extant in judicial records or in both, and therefore, being collected together, shall (as we perceive) produce certainty.

Instead of the analytical approach used in Roman law, the common lawyers advocated a historical approach wherein individual reason would be constrained by the experience embodied in actual judicial decisions collected over hundreds of years. Francis Bacon reflected the ideas of a common lawyer when he stated that one should make the rule from existing law. General maxims were not to be the product of arid disputations, but were to be gathered and extracted out of the harmony and congruity of cases. The danger inherent in the use of pure reason was that it was more liable to lead to arbitrariness and uncertainty because it was overly speculative and not grounded in the actual problems associated with legal decisions. Chief Justice Matthew Hale put the case clearly when he maintained that those with the greatest power of natural reason *are most commonly the worst judges that can be, because they are transported from the ordinary measures of right and wrong by their overfine speculations, theories and distinctions.2

As quoted in Holdsworth, A Hislorv of English I aw, vol. IV, p. 226. Coke was Lord Chief Justice of the Court of Common Pleas,*and for many years was Bacons rival for royal support. He was the author of The Institutes. which, together with the works of Bacon, came to be used by some revolutionaries in the 1640s as their grounds for the authority of Parliament. This argument could be made since the common law was seen as a constraint on the absolute power of the sovereign. See Thomas Andrew Green, Verdict According to Conscience (Chicago: University of Chicago Press, 1985). p. 163; Levack, The Civil Lawyers, pp. 123, 144; David Ogg, England in the Reign of Charles II, Vol. I (Oxford: Clarendon Press, 1955). Lawyers themselves were divided in their allegiance during the civil war, and a number of prominent legalists had been leaders of the opposition to Crown policy. See Richardson, A History ofrhe Inns of Courf, pp. 29&291.

Holdsworth, A History of English Law. vol. IV, p. 226. Francis Bacon, De Augmenfis, Bk. VIII, aph. 85 in The Works. vol. IX, p. 338. Book VIII is

not a treatise on common law, but it does reflect Bacons preference for the common law procedure of historical precedent when dealing with civil matters.

Francis Bacon, Maxims of the Law, Preface. in The Works, Vol. XIV. p. 181. Matthew Hale, Reflections by the Lord Chief Justice Hale on Mr. Hobbes his Dialogue of

the Law. Manuscript printed as an appendix to Holdsworth, A History of English Law. vol. V, pp. 500-506; p. 503. I have modernized Hales spelling. Thomas Hobbes, in his A Dialogue


In order to be a competent judge of legal affairs, one had to acquire legal reason - an instinctive ability to reason on the law, which could not be taught but only resulted from a deep and prolonged exposure to the working of the law. 21 As Coke described it. the common law is:

not to be decided by natural reason but by the artificial reason and judgment of law, which law is an act which requires long study and experience, before that a man can attain to the cognizance of it.22

Once equipped with this artificial perfection of reason, the lawyer would have the experience necessary for the discernment of similarities and differences in past cases and for the analogical application of these precedents to new cases. In the construction and application of a law, experience had to guide the use of reason.23 But clearly, this type of experience is not that which is today commonly associated with sense perception or mere observation. When the lawyers claimed an experiential foundation for the justification of their decisions, they did not appeal merely to an accumulation of facts, but to a sophisticated process of interpreting the facts. Reason was not (and could not be) excluded. But it had to be restrained more than it was in the case of those speculators that take upon them to correct all the governments in the world and to govern them by certain notions and fancies of their own.24

The common lawyers did not claim that experience could yield infallible judgments, but maintained that it was preferable to adopt laws that had

Between a Philosopher and a Student of the Common Laws of England [in vol. VI of The English Works of Thomas Hobbes, William Molesworth (ed.) (London: John Bohn, 1840), pp. l-160], championed the analytical approach to the law. Hale criticized Hobbes on two points: (1) the weakness of a purely analytical and logical criticism of existing laws and (2) Hobbes doctrine of absolute sovereignty. Not surprisingly, in his Dialogus Physicus [Simon Schaffer (transl.) in Leviathan and the Air-Pump, pp. 3463911 Hobbes was opposed to experimental science and championed a rational, mathematical approach instead.

*See Richardson, History of the Inns of Court, pp. 91-150, for the fullest account of education at the Inns. See also Baker, Reports of Spelman, vol. II, pp. 161-163; and Ives, The Common Laywers, pp. 37-38, 158-161; for the common erudition learned at the Inns.

Richardson, History of the Inns of Court, pp. 148-149. 3Precedent was only a guide because it was notstrictly binding. See Baker, Reports of

Spelman, vol. II, pp. 161-163. Individual cases had small authority, the common opinion based upon a number of cases carried more weight.

Hale, Reflections, in Holdsworth, A History of English Law, vol. V, p. 506. Jardine, Francis Bacon, has argued that Bacons Great Instauration should be viewed as being in line with the dialectical tradition. However, her argument does not seem to do much more than establish that he was motivated by his aversion to dialectic, which would be a typical response of a common lawyer. Common lawyers believed that a training in logic and dialectic was a necessary preliminary to the study of law, but when Abrahm Fraunce, a member of Grays Inn at the time of Bacon, published his Lawyers Logicke in 1588, it was viewed as little more than an English translation of the dialectic of Ramus and received little attention. See Prest, The Inns of Court, pp. 132-146, and Richardson, History of the Inns of Court, pp. 147-149. The usefulness of logic was for the development of natural reason, but the study of law involved the development of legal reason.

proven successful over time rather than to follow the dictates of individual

reason. As Hale wrote:

. the unknown, arbitrary, uncertain judgment of the uncertain reason of pilrticular persons, bath been the prime reason, that the wiser sort of the world have in all ages agreed upon some certain laws and rules and methods of administration of common justice, and these to be as particular and certain as could be well thought of.s

Rather than speculating on first principles of moral philosophy, the lawyers

sought practical solutions to actual problems.2 Because of the lack of

universal principles, Hale and his fellow lawyers noted that conclusions were

much more difficult to reach in the field of law than in abstract mathematical

sciences which possessed such principles from which conclusions could be

logically deduced. Further, when found, the legal conclusions would

obviously not share the deductive certainty of mathematical demonstrations.

But mathematical demonstration was not the lawyers ideal: Indeed, it was a

foolish and unreasonable thing to expect a mathematical demonstration in

such an area. According to Hale:

Of all kind of subjects . there is none of so great a difficulty for the faculty of reason to guide itself and come to any steadiness as that of laws . , when it comes to particulars. And, therefore it is not possible for men to come to the same certainty, evidence and demonstration touching them as may be expected in mathematical sciences.

Mere reasoning is not sufficient. Unlike the mathematician who could

consider the relations between abstract definitions, the lawyer needed

experience of how similar cases in the past had been resolved and how these

precedents should apply to the present case. But the common law did have a

method of proof, sometimes referred to as moral demonstration, that was

considered superior to mathematical demonstration. The manner by which

this type of proof was achieved can be seen in the way that trials were

conducted. Here again. there was a marked difference between Roman law

and common law.2

Ibid., p. 503. Baker, Reports of Speltnan, vol. II, p. 29. Hale, Reflections. p. 505. ibid., p. 502. Compare this with Bacon, De Augmentis. Bk. VllI, ch. 1, in Tlze Works, vol.

IX. p. 232: Civil Knowledge is conversant about a subject, which of all others is most immersed in matter, and with most difficulty reduced to axioms.

Boyle, as we will see in the next section, considered legal proof to he of the type that he called moral demonstration. It is important to note that the lawyers did not reluctantly settle for moral demonstration as an inferior mode of proof. Rather. they believed that for their subject, it was superior to analytic reasoning and dialectic.


Roman law required complete proof (probatio pfena) before a verdict could be reached. Proof did not consist in the balance of persuasion. Rather, strict mechanical rules of evidence were followed. Different pieces of evidence carried different numerical values (from 0 to l), and by a simple arithmetical calculus, complete proof was achieved when these values totalled 1. If the evidence provided only a probario semi-plena, then other measures, such as torture, were employed to obtain certainty. The method of taking evidence consisted of questioning witnesses in private and then introducing their depositions as evidence to a closed court. Based upon this evidence, the judicial bench would determine the facts of the case and pass legal ruling on its own findings. In common law, on the other hand, trials were a public affair, and witnesses testified in an open court. A jury of 12 men would deliver their verdict on the facts of the case, and the bench would pass judgment on their verdict. There was a sharp boundary of duties in the trial court: the jury had the responsibility of deciding matters of fact, while it was the task of the judges to decide matters of law.32

The common law courts did not require a complete proof in order for a verdict to be reached by the jury. Originally, the method of proof, derived from the Anglo-Saxon law of the ninth century, was that of cornpurgation. Jurors were chosen on the basis of the knowledge that they had of the case before the court, frequently coming from the same neighborhood as the accused. Compurgators (witnesses) would take an oath and the truthfulness of their testimony would be judged by the jury. While by the 17th century the procedure had changed somewhat - jurors prior knowledge was not always possible or desirable - in practice the jury frequently retained its self-

Langbein, Prosecuting Crime in the Renaissance, pp. 237-239; Holdsworth, A History of English Law, vol. V, pp. 17S187. Torture was used because a confession carried the value of 1. England also used torture for serious crimes, but there were no apparent criteria for when or why it would be used.

Langbein, Prosecuting Crime in the Renaissance, p. 211; Holdsworth, A History of English Law, vol. V, pp. 169-175.

See Langbein, Prosecuting Crime in the Renaissance, p. 251. for the distinction between matters of fact and matters of law. The jury, for example, would find homicide. and the bench would decide if it was murder or manslaughter and pass sentence accordingly. See Holdsworth, A History of English Law, vol. V, pp. 195-196 for the open, public nature of trials. See Green, Verdict According to Conscience, pp. 110-111; and Baker, Reports of Spelman, vol. II, pp. 92-100, for the necessity of oral testimony. By the 17th century the practice of written depositions had been introduced into English law, but they were not part of the official record and were not binding. An example of all of these factors can be found in the 1649 Trial of Lieutenant-Colonel John Lilburne, in: State Trials, compiled by T. B. Howell, 21 vols. (London, 1816), vol. IV, pp. 1270-1470. Also in this trial one can see the great amount of freedom that the defendant had to speak in contrast with the Roman procedures where the defendant was extremely limited in what he could say and when he could say it. See Langbein, Prosecuting Crime in the Renaissance, p. 237; and Holdsworth, A History of English Law, vol. V pp. 169-175.


informing role. 33 If the evidence was incomplete, for example, the jury could proceed upon its knowledge. The final decision was to be based upon the probable merits of the cases put forth by the accused and the accuser, and the case would be decided in favor of the one whose account appeared to them most likely to be true. The proof of the case was said to consist in the finding of a body of reasonable men, according to the probabilities of the case.s4

In opposition to the notion of a mathematical demonstration, and the Roman law notion of strict numerical probability, the common law offered a model of demonstration in which experience was fundamental in the determination of the reasonable resolution of cases. The experiential foundation of the lawyers went beyond a mere accumulation of facts to a reasoned interpretation of the facts. Their notion of experience relied heavily on the idea of an expert.

The expert was one who had mastered the common erudition; who had developed his reason by experience in a specific area and was thus the most qualified to judge in that area. 35 The jury would have expert status in the judgment of the veridical nature of the witnesses testimony, by virtue of their past experience of the reputations of the accused and the witnesses, and thus of the likelihood of the matter of fact having occurred. The judge (a lawyer) was the expert, who, by reason of his long experience of the workings of the law, was able to deliver the best judgment on matters which related to the interpretation of the facts and the resolution of the case. In the process of rational adjudication, the use of background knowledge was necessary both for the establishment of the facts and the application of past cases that would determine the relevance and interpretation of the facts. This same broad notion of experience, and the type of demonstration grounded upon it, played an integral part in the attempts by English experimentalists to justify the knowledge-producing character of their enterprise. This can be seen most clearly in the case of Robert Boyle, who, expanding upon the methodological precepts of Bacon, made frequent use of the lawyers arguments in the interest of advancing the cause of experimental philosophy.

III. Boyles Experimental Philosophy

Boyle, the leading advocate of the new experimental philosophy in

Baker, Reporfs ofSpelman, vol. II, p. 107-112; Holdsworth, A History ofEnglish Law, vol. II, pp. 108-117; vol. III, pp. 59-34; and Green, Verdict According to Conscience, pp. lOC107, 142. The jurors were told to judge according to the evidence and your conscience.

Holdsworth, A Hisfory of English Law, vol. III. p. 633. The right of the accused to challenge the testimony of his accusers turned the trial into a proper test, according to Green, Verdicf According fo Conscience, p. 136.

Baker, Reports of Spelman, vol. II, p. 124.


England, saw himself as continuing Bacons program.36 As is well known, Bacon was highly critical of those who placed too much emphasis on the use of the rational faculty, and he sought to counteract this tendency in natural philosophy by stressing the need for experiment. But he was also critical of those of his contemporaries who relied upon experiments, because the manner of making experiments which men now use is blind and stupid, . . . wandering and straying, . . . with no settled course.37 To the Lord Chan- cellor, the remedy was clear. Natural histories had to be constructed in the manner in which legal histories had been:

. . . the use of History Mechanical is, of all others, the most radical and fundamental towards natural philosophy; such natural philosophy I mean as shall not vanish in the fumes of subtle and sublime speculations.38

Not surprisingly, he maintained that the best demonstration by far is experience.3 Because the mind is possessed by idols that distort our image of the world, reason alone cannot produce true theories:

. . . that method of discovery and proof according to which the most general principles are first established, and then intermediate axioms are tried and proved by them, is the parent of error and the curse of all science.4

Bacon had admonished philosophers to seek knowledge not arrogantly in the little cells of human wit, but with reverence in the greater world, and Boyle agreed that to the extent that the classical way of reason failed to make contact with the actual world it was an inappropriate method for natural philosophy.4 In his view, the philosophical task was the determination of:

. . . how things have been, or are really produced; not whether or no the manner of their production be such, as may the most easily be understood by us . . that way may often be fittest or likeliest for nature to work by, which is not easiest for us to understand.42

hLaudan, The Clock Metaphor and Hypotheses, p. 52, maintains that Boyles numerous references to Bacon should be seen as mere lip-service to a famous fellow-countryman.

Bacon, The New Organon, Bk. I, aph. lxx in The Works, vol. VIII, p. 100. 38Bacon, De Augmentis, Bk. II, ch. 2, in The Works, vol. VIII, p. 415. On p. 410 (ibid.) he

described Mechanical and Experimental History as that which puts nature in constraint, in contrast with History of Generations where nature follows her ordinary course of development. His natural histories were meant to be more than mere collections of facts since experimental histories were part of them and nature exhibits herself more clearly under the trials and vexations of art than when left to herself. (Ibid., p. 415.)

Bacon, The New Orgunon, Bk. I, aph. lxx, in The Works, vol. $111, p. 100. Ibid., Bk. I, aph. Ixix, D. 100. This is a criticism of the Aristotelians. but it would easilv aoolv

also to the methbd that i)escartes was to develop. 4lbid., Preface, p. 37. 2Boyle, The Usefulness of Natural Philosophy, vol. II, p. 46.

, L.,


The rationalists, who content themselves with the superficial account

given us of things by their obvious appearances and qualities, he likened to

the Baconian spider in a place who

taking notice only of those objects, that obtrude themselves upon her senses, lives ignorant of all the other rooms in the house, save that wherein she lurks; and discerning nothing either of the architecture of the stately building. or of the proportion of the parts of it in relation to each other. and to the entire structure, makes it her whole business. by intrapping of flies, to continue a useless life or exercise herself to spin cobwebs, which though consisting of very subtile threads, are unserviceable for any other than her own trifling uses.

He did not discount the use of reason. Rather, reason had to be improved by

meditation, conferences, observations and experiments, that need not

destroy a dictate of reason, but only give it a limitation and restrain it.4

Boyle wished to speak physically of things and pure reason is not sufficient

for that task. But, neither is mere observation sufficient for revealing truths

about those causes actually operative in the world. The appreciation of the

complexity and subtlety of the world created a demand for a new science to be

built upon two foundations, reason and experience.4 For the physical

world, the use of natural reason and common observation is not sufficient; the

testimony of nature is also necessary, and one needs experience in order to be

able to ask the right questions of nature and to interpret the answers.

Experimentation was to be the method by which one was to discover, by

artifice and skill, things that were hidden from common observation:

The experimental philosopher is not a mere empiric who too often makes experiments. without making reflection on them, as having it more in his aim to produce effects, than to discover truths.

/bid.. p. 9. For Bacon. the spider represented reasoners who make cobwebs out of their own substance (The New Orgmon. Bk. I. aph. xcv, in The Works, vol. VIII, p. 131). Boyle expanded somewhat upon the spiders activities, but the conclusion is the same - the experimentalist is to use both sense and reason.

Boyle, The Christim Virtuoso. vol. VI, p. 715. SBoylc, The Origin of Quuiiries. vol. III. p. 25. *Boyle, The Christian Virtuoso. vol. V, p. 512. l&d., p. 524. This is an obvious reference to Bacons distinction between experiments of light

and experiments of fruit. in The New Organon, Bk. 1, aph. xcix, in The Works. vol. VIII, p. 135. Also. in Dr Augmentis, Bk. II, ch. 2, in The works. vol. VIII, p. 415, Bacon maintained that History mechanical will give a more true and real illumination concerning the investigation of causes of things and axioms of arts. than has hitherto shone upon mankind. The difficulties encountered in the discovery of causes will be discussed below. But it is important to note here that while Boyle wished to discover actual causes. he did not restrict a knowledge of them to the observational level. Observations were only one of a number of constraints on theory- building; they did not play the empirical role of a straight-forward criterion for the truth of a theory - indeed. frequently observations had to be corrected by the use of theories. As we will see. theories do not simply fall out of, and receive their complete warrant from, experimental results.


Boyle did not regard reason and experience as contrary notions. To gain experience of the world, we must make reflections on the information of the senses, and not simply receive sense impressions passively.4x We must do more than look at the world, we must actively investigate it. The information of the senses could not provide an evidential warrant for a theory until it had been itself validated by experimental trials. But even the experiments designed for this investigation could miscarry. Contingencies of experiments resulted from the presence of such circumstances as are very difficult to be observed, or seem to be of no concernment to an experiment but yet may have a great influence on the event of it.4 When working with metals, for example, the experimenter must be very cautious because samples may appear perfectly similar to the eye yet small quantities of other metals may lie concealed, and their presence is hardly to be discerned before experience have discovered it. The experience used here to decide the issue is to be gained either from exquisite separations or from unexpected operations exhibited in experimental trials.5 By manipulating nature, we not only increase the quantity of information that we have of natural processes, we improve the quality of that information by extending our knowledge of the world beyond that of the mere appearances which could be had from common observation.

The difficulties encountered entail, not that experimental science cannot yield knowledge, but that an immense amount of labor and skill is required for the proper design of experiments and the validation of our interpretations of the results. Repetition and variation of the experimental conditions are necessary. As Boyle reminds his readers, he provides numerous examples of the contingency of experiment so that they would realize the obligation:

. . . to try those experiments very carefully, and more than once, upon which you mean to build considerable superstructures, either theoretical or practical; and to think it unsafe to rely too much upon single experiments5

*Boyle, The Usefulness of Natural Philosophy, vol. II, p. 9. Boyle, Of Unsucceeding Experiments, in: Certain Physiological Essays, vol. I, p. 340. In

medicinal remedies, for example, a drug could be effective for the cure of a specific disease, but could result in the death of the patient nonetheless because of some unforeseen or unheeded condition in the particular patient that made the drug either too strong or too weak to be effective. He also noted that a patients expectations could influence the effectiveness of the cure. Interestingly, Hale used the medical analogy to illustrate legal procedures: But the texture of human affairs is not unlike the texture of a diseased body ., it may be of so various natures that such physic as may be proper for the cure of one of the maladies may be destructive in relation to the other and the cure of one disease may be the death of the patient. Hale, Reflections, p. 503.

Ibid., p. 322. Ibid., pp. 348-349. Repetition and variation are techniques required to validate that the

experiment can be used as a legitimate piece of evidence.

32 Studies in History and Philosophy ofScience

But the difficulties were not meant to produce such a despondency of mind,

as may make you forbear to prosecute them.52

The experimentalist is neither rationalist nor empiricist. The information of

the senses and reason can both mislead. The demand for repetition indicates a

distrust of the senses, but reason is equally suspect: judgments of reason

are only fit to be relied on, according as the informations they are grounded

on are more or less certain and full.5 Boyles program was designed as a

means by which both the sensory and rational faculties would be used to their

best advantage primarily by being used as constraints upon each other. The

study of contingent matters requires a methodological strategy similar to that

which is found in the law. It is a strategy of rational adjudication by which the

evidence is carefully collected, weighted, and verified. Based upon this

evidence, reason then decides on the truth of the matter. The method is

fallible. The truths obtained from it will not possess the metaphysical

necessity of Cartesian first principles, but will be limited to a knowledge of

how things are actually produced in the world as it is now constituted. As

Boyle explained, the experimental philosopher does not seek axioms

metaphysical or universal but rather axioms collected or emergent, by

which I mean such as result from comparing together many particulars.

These axioms are so general that they rarely admit of exceptions yet they may

not be unlimitedly true.54 Experimental science may also sometimes fail to

identify even such limited truths. But all that is required for a justification is

that the method often succeeds, not that it never fails. The striking

experimental success of Harvey and Galileo, for example, provided a

precedent for the future success of experimental science. As Boyle

explained, physicians and merchants do not forsake their businesses because:

. though they sometimes miss of their ends, yet they oftentimes attain them, and are by their successes requited not only for those endeavours that succeed, but for those that were lost, so ought we not by the contingencies incident to experimental attempts, to be deterred from making them.s6

The experimental philosophy is both a method of discovery (it establishes

the facts upon which theories are to be constructed), and a method of

Ibid., p. 352. 3Boyle, The Christian Virtuoso, vol. VI, p. 707. 54BovIe, Things Said to Transcend Reason. vol. IV, p. 462. Bo;le held bbth men in high esteem. For his frequent yeferences to Harvey, see Richard A.

Hunter and Ida MacaIDine. William Harvev and Robert Bovle. Notes and Records ofthe Roval Society of London 13 i1958). 115-127. For Boyles referencks to Galileo, see, for example, fhe Usefulness of Natural Philosophy, vol. III, esp. p. 467, where he calls Galileo the great master of mechanics.

ShBoyle, Of Unsucceeding Experiments, vol. I, pp. 352-353.

Scientific Experiment and Legal Experfise 33

justification (it provides rigorous testing procedures by which the resultant theories are to be proven). In a manner reminiscent of the lawyers arguments in favor of moral demonstration, Boyle argued that, despite its fallibility, a demonstration produced by experimental science is superior to one produced by the mathematical way of reasoning. The way of reason produces an axiomatic system that assures the certainty of its conclusions by virtue of its logical structure. But Boyle was suspicious of the knowledge claims thus produced, for a number of reasons. First, he was troubled by the general nature of mathematical demonstrations that are built upon supposition and postulates . . . about which men are liable to slip into mistakes.57 The arbitrary nature of the postulates put forth by mathematical writers entailed. for him that:

. . the certainty and accurateness, which is attributed to what they deliver must be restrained to what they teach concerning those purely-mathematical disciplines, arithmetic and geometry, where the affections of quantity are abstractedly considered.58

Secondly, the problem with the systems produced by famous philosophers was that they had presumed to give us general axioms upon insufficient inductions, and without thoroughly penetrating the differing natures of the things included in those comprehensive axioms.5y Reason must be guided by the information of sense, and by experience:

It cannot but be a satisfaction to a wary man to consult sense about those things that fall under the cognisance of it, and to examine by experience, whether men have not been mistaken in their hypotheses and reasonings.ti

Finally, while mathematics was a useful and necessary tool for the advancement of natural philosophy, its use was limited to proving the truth of descriptive laws about the world; it could not take us beyond to the physical causes responsible. In hydrostatical investigations, for example:

Boyle, Hydrostatical Paradoxes, vol. II, p. 142. Previous studies have given the impression that Boyle did not understand mathematics. For example, A. R. Hall, The Scientific Revolution, 2nd edn (Boston: Beacon Press, 1983), p. 278, states that Boyle had no natural aptitude towards the mathematization of nature. In works such as the Hydrostatical Paradoxes, however, Boyle does display his knowledge of mathematics. The absence of mathematical demonstrations in his work should be attributed to his philosophical arguments against reasoning more geometrico and to his interest in the qualitative aspects of natural philosophy.

Boyle, Of Unsucceeding Experiments, vol. I, p. 347. Boyle, The Christian Virtuoso, vol. VI, p. 705. MBoyle, Hydrostatical Paradoxes, vol. II, p. 742.


those mathematicians, that (like Marinus Ghetaldus Stevinius, and Galileo) have added anything considerable to the Hydrostaticks, . . have been wont to handle them rather as geometricians, than as philosophers, and without referring them to the explication of the phaenomena of nature.h

For Boyle, the importance of hydrostatical inquiry extended beyond proving

that certain propositions were true, to the explanation of why they ought to

be SO.~~ The first task was largely mathematical. The second was the true

province of natural philosophy.

Natural philosophers are obliged not only to know the general laws and

course of nature, but to inquire into the particular structure of bodies.6

Corpuscularianism, in the sense newly given it by Boyle,4 is a physical

doctrine designed to explicate the phenomena by real, though extremely

minute bodies.65 He advocated the corpuscular hypothesis because it

Ibid.. p. 740. In his Usefultless qf Nutural Philosophy. vol. III. p. 477, he argued for the usefulness of mathematics, stating that many properties and uses of natural things are not likely to be observed by those men, though otherwise never so learned, that are strangers to the mathematicks.

Boyle, Hydrostatical Paradoxes, p. 746. Compare this with Bacons advice in The New Organon. Bk. I. aph. xcvi. in The Works, vol. VIII. p. 132. that mathematics ought only to give definiteness to natural philosophy, not to generate or give it birth. See Peter Dear Jesuit Mathematical Science and the Reconstitution of Experience in the Early Seventeenth Century, Studies in History und Philosophy of Science 18 (1987). 133-175. for a discussion of the distinction between mathematical and physical sciences. Dear traces what he finds to be a transformation in the term experience from the Aristotelian notion of a universal evident statement used as a premise in a scientific demonstration to the notion in the 17th century of a discrete historical event. With this transformation, Dear argues that expertise and witnessing became fundamental to the establishment of facts that could be used as evident suppositions in scientific argument. Boyles notion of experience does not seem to fit well within this discussion. The facts established by experience are not discrete events but are regularities, e.g. that animals will die ten times faster in a pump from which most of the air has been removed than from one left full. But these regularities are not to be used as suppositions in scientific explanation. Rather they are the facts to be explained by science. If Dear is right, it would seem that there were (at least) two experimental traditions: one that derived from the mathematical sciences, and one from the low sciences of law. chemistry and medicine.

Boyle. The Origirz of Qualities. voi. III, p. 75. In his Received Notiorl of Narure. vol. V. p. 170, Boyle denies that a law can define the nature of a body because a law omits the general fabric of the world and the contrivances of particular bodies that are necessary to produce effects.

hJBoyle, Certain Physiological Essays, vol. 1, p. 356. h5Boyle, Experiments Touching Colours, vol. I, p. 746. Boyles corpuscularianism is

different from the mechanical philosophy of others. See Stillman Drakes discussion of Galileos shift from the Aristotelian search for causes to the quest of laws of nature based on experiment and measurement [Cause, Experimenl and Science (Chicago: University of Chicago Press, 1981), p. ix]; and Lisa Sarasohns discussion of the mechanical philosophy of Gassendi and Hobbes where the law of inertia had the central explanatory role. (Motion and Morality: Pierre Gasscndi. Thomas Hobbes and the Mechanical World-View, Journal of the History of Ideas 46 (19X5), 36.3-379.) Although Boyle was a vocal critic of Aristotelianism, he retained the notions of formal and final causality by transforming them into notions compatible with his corpuscularianism. See Peter Alexander, Ideus, Qualities and Corpuscles; Norma E. Emerton, The Scientific Reinrerprekztion of Form (Ithaca: Cornell University Press, 1984); Marie Boas Hall, Roherr Boyle


avoided the occult qualities and forms of the Aristotelians and chemists, and was more fertile and comprehensive than the previous doctrines. For example, even if the elements of the chemists could be proven to exist, these ingredients would still owe their nature to a union of insensible particles.66 Yet, he sided with the chemists who believed that the current formulations of corpuscularianism consisted of empty and extravagant speculations, because the theorists pretend to explicate the great book of nature, without having so much as looked upon the chiefest and the difficultist part of it [chemical combinations].67 In his view, the corpuscular philosophy is a physical hypothesis, and therefore its tenets have to be proven by experience. For this purpose, he maintained that there are scarce any experiments, that may better accommodate the Phaenician [corpuscular] principles, than those that may be borrowed from the laboratories of the chymists.68

Corpuscles are unobservable in principle. They are invisible causes and their manner of existence can only be known by inference from the effects that they produce. 6y The eye or the imag ination can never reach to so small an object as an atom, but, there is no necessity . . . that visibility to a human eye should be necessary to the existence of an atom, or of a corpuscle of air, or of the effluviums of a loadstone. Neither common observation nor mathematical analysis will reveal the manner by which the corpuscles produce their effects; only experimentation will do so. Boyle remarked that his reflection on the phenomena of nature led him to appreciate the intel- ligibility of the corpuscular philosophy, and that his acceptance of this philosophy in turn led him to realize the necessity of an experimental

and Seventeenth Cenrury Chemistry (Cambridge: Cambridge University Press, 1958); and James G. Lennox, Boyles Defense of Teleological Inference, Isis 74 (1983), 38-52. It seems that it was largely his interest in chemistry that separated Boyle from other mechanical philosophers and this interest led him to a different formulation of the experimental ideal.

OhBoyle, The Grounds of the Mechanical Philosophy, vol. IV, p. 14. Thomas Kuhn, in his Robert Boyle and Structural Chemistry in the Seventeenth Century, Isis 43 (1952), 12-36, argued that Boyle set back the progress of chemistry because he refused to accept the existence of elements. But, as Hall, Robert Boyle and Seventeenth Cenrury Chemistry, has pointed out, the elements that Boyle denied were the universal ones that the chemists posited as existing in any body whatsoever.

Boyle, Certain Physiological Essays, vol. I, p. 358. Ibid. Chemical experiments could show what nature contributed in chemical combinations,

since the experiments were done in closed transparent vessels, so that one could better know what concurs to the effects produced, because adventitious bodies are kept from intruding upon those, whose operations we have a mind to consider. (Ibid.) See the correspondence between Henry Oldenburg, on behalf of Boyle, and Baruch Spinoza, on the need to experimentally establish corpuscular doctrines, in: The Correspondence of Henry Oldenburg, vols I and II, A. R. Hall and M. B. Hall (eds) (Madison: University of Wisconsin Press. 1965).

6Boyle, Cosmical Qualities of Things, vol. III, p. 315. Corpuscles are unobservable in principle because they possess only primary qualities and it is the secondary qualities produced by their joining together into various configurations that produce sensible qualities in us.

Boyle, The Christian Virtuoso. vol. VI, p. 694. In Things Said to Transcend Reason. vol. IV, p. 469, Boyle explained that our illative knowledge is clearer and extends further than our intuitive or apprehensive knowledge.


method. He sought to discover qualitative explanations of the quantitative

laws described by other mechanical philosophers. To infer actual causes

correctly, one first needs to determine the effects to be explained, and then,

since a number of different possible causes may be inferred, one also needs to

confirm the hypothesis by experiment, by the careful testing of the further

consequences entailed by it. Qualitative corpuscular hypotheses that explain

in terms of real corporeal particles must be proven a posteriori if they are to

be properly grounded in experience. Those that are so grounded will

peaceably obtain discerning mens approbation.72

The physical realm was not considered by Boyle to be part of the realm of

mathematical demonstration. Because experimental philosophy was to follow

the way of experience, as opposed to the way of reason, moral demonstra-

tion, such as that which was advocated by the lawyers, was the preferred

mode of proof. Moral demonstration may not be as rigid as mathematical

demonstration, but it is superior in its ability to reveal truths about the world.

As Boyle put it, there are many truths that:

. by the nature of the things are not capable of mathematical or metaphysical demonstrations, and yet, being really truths, have a just title to our assents; it must be acknowledged, that rational assent may be founded upon proofs, that reach not to rigid [i.e. mathematical] demonstrations, it being sufficient that they are strong enough to deserve a wise mans acquiescence in them.

He retained a skeptical attitude toward a number of philosophical

positions. One ought to suspend judgment if there is a specific reason to

doubt. But, there are times when there is no such reason. If all of the

evidence points to one side of the issue, and there is no evidence on the other

side that would militate against it, then the reasonable course is to affirm the

conclusion. Moral demonstration could yield undoubted assent. Of course,

one could be mistaken. Judgments about the contingent world remain

fallible, but this general skeptical conclusion does not provide a specific

reason to doubt. It would be unreasonable to continue to doubt in the face of

overwhelming evidence.

Moral demonstration is demonstrative. Its strength, as a mode of proof, is

clearly exhibited in a passage where Boyle describes moral demonstration as

that which is:

made up of particulars, that are each of them but probable; of which . . . the practice of our courts of justice here in England, affords us a manifest instance in

Boyle, The Origin of Qualities, vol. III. p. 75. 72Boyle. The Grounds of the Mechanical Philosophy, vol. IV. p. 77. Boyle, Things Said IO Trarmend Reason. vol. IV. p, 449.


the case of murder, and some other criminal cases. For, though the testimony of a single witness shall not suffice to prove the accused party guilty of murder; yet the testimony of two witnesses, though but of equal credit, that is, a second testimony added to the first, though of itself never a whit more credible than the former, shall ordinarily suffice to prove a man guilty; because it is thought reasonable to suppose, that, though each testimony single be but probable, yet a concurrence of such probabilities, (which ought in reason to be attributed to the truth of what they jointly tend to prove) may well amount to a moral certainty, i.e., such a certainty, as may warrant the judge to proceed to the sentence of death against the indicted party.74

A conclusion built upon a concurrence of probabilities cannot be but allowed, supposing the truth of the most received rules of prudence and principles of practical philosophy.75 Moral demonstration is a form of practical judgment that is concerned with rational assent. Boyles standard of rationality does not consist in a mere multiplication of testimony, but in the amount of independent evidence for the proposition in question:

. . . when we are to judge, which of two disagreeing opinions is most rational, i.e. to be judged most agreeable to right reason, we ought to give sentence, not for that, which the faculty, furnished only with such and such notions, whether vulgar, or borrowed from this or that sect of philosophers, would prefer, but that, which is preferred by the faculty, furnished, either with all the evidence requisite or advantageous to make it give a right judgment in the case lying before it, or, when that cannot be had, with the best and fullest information, that it can procure.

A judgment of reason is that which takes in the most information procurable, that is pertinent to the things under consideration.

While Boyles discussion of concurrence and reasonable assent take place within a treatise devoted to an examination of the reasonableness of religion, these ideas were also fundamental to his experimental philosophy. In his Examen of Mr. Hobbess Dialogus Physicus, Boyle approved of Hobbes two criteria for the evaluation of a hypothesis, its conceivability and its

74Boyle, Some Considerations about Reason and Religion, vol. IV, p. 182. Boyles description is a bit condensed, but basically right. It would be the jury that would find the accused guilty, based upon the concurrence of probabilities, and then the judge would pass the sentence of death upon their indictment. See Green, Verdict According to Conscience, pp. 180-181.

Ibid. The concurrence produces a type of hypothetical necessity: if one wants to be rational, then one ought to assent to the conclusion.

761bid., pp. 179-180. In this context, it is interesting to note one of Kuhns examples of a paradigm which is said to be like an accepted judicial decision in common law, it is an object for further articulation and specification under new and more stringent conditions. The Structure of Scientific Revolutions, p. 23. Legal analogies seem to naturally come to mind in experimental contexts; see, e.g., Peter Galison, How Experiments End (Chicago: University of Chicago Press, 1987), p. 277: experiments are about the assembly of persuasive arguments, ones that will stand up in court .

Ibid., p. 181.


explanatory power, but added a third criterion: that it be not inconsistent

with any other truth or phaenomenon of nature.7x A theory is worthy of

approbation if it comports with all other phaenomena of nature as well as

those it is framed to explicate. This additional criterion increases the

amount of phenomena for which a hypothesis must account, and it is the

experimentalists duty to test the consequences of a hypothesis to ensure that

there are no phenomena inconsistent with it. As Boyle explained, an

excellent hypothesis is one that enables:

. . a skilful Naturalist to foretell future Phenomena, by their Congruity or Incongruity to it; and especially the Events of such Expts as are aptly devised to Examine it; as Things yt ought or ought not to be Consequent to it.x

The more tests a hypotheses withstands, the more reason we have to believe

that it is not a mere mental construct. The purpose of a hypothesis is:

. to render an intelligible account of the causes of the effects, or phaenomena proposed, without crossing the laws of nature, or other phaenomena; the more numerous, and the more various the particles are, whereof some are explicable by the assigned hypothesis, and some are agreeable to it, or at least are not dissonant from it, the more valuable is the hypothesis, and the more likley to be true. For it is much more difficult, to find an hypothesis, that is not true, which will suit phaenomena, especially if they be of various kinds, than but with a few.

Boyle, Examen of Mr. Ho&ess Dialogus Physicus. in: New Experiments Physico- Mechanical, vol. I., p. 241.

Boyle, The Excellency of Theology, vol. IV, p. 59. Quoted by Richard S. Westfall in: Unpublished Boyle Papers Relating to Scientific

Method, Annals of Science 12 (1956), 63-73, 103-117, p. 117. This third criterion is reminiscent of the testing procedure suggested by Carneades. As Ralph Doty describes it, a person seeing something coiled on the floor of a barn at night would prod the coiled object with a stick to determine whether it is a rope or a snake. This would be an experiment *aptly devised, since background knowledge would inform one that snakes react differently to prodding than do coils of rope. It is significant that Boyle chose Carneades. rather than one of the more radical Pyrrhonists. as his spokesman in the Scepfical Chymist. See Ralph Doty, Carneades. A Forerunner of William Jamess Pragmatism, Journal of the History of Ideas 47 (1986). 133-138. See also. Douglas Lane Patey, Probability and Liferury Form (Cambridge: Cambridge University Press, 1984), pp. 15-16, for his discussion of Carneades method of probability.

Boyle, Experiments, Nores, Etc., vol. IV. p. 234, italics mine. Compare this with John Lockes discussion of probability in: An Essay Concerning Human Understanding, Peter H. Nidditch (ed.) (Oxford: Clarendon Press, 1975), Bk. IV, Ch. 16, $6, p. 662, where he states that probabilities based upon the nature of things and the testimony of reliable witnesses rise so near to Certainty, that they govern our Thoughts as absolutely as the most evident demonstration. Locke is here talking about probabilities concerning matters of fact, and acknowledges that when one turns to hypotheses about unobservables, probability is more difficult to achieve. Yet, in Bk. IV, ch. 16, $12, pp. 66&667, he maintains that wary Reasoning from Analogy (e.g. the principle that like effects have like causes) leads us often into the discovery of Truths, and useful Productions, which would otherwise lie concealed.


A theory that accounts for all of the known phenomena is probable. A positive evaluation is called probable, rather than true simply because the evidence upon which it is grounded is incomplete. Boyle cited the fact that the recent invention of the telescope and other philosophical instruments had increased the amount of information in the natural histories upon which theories were to be built and there was reason to believe that these histories would continue to grow in the future.s2 A theory would either remain probable, or become improbable, as new information came to light. The probabilism expressed here is not one that reflects any in-principle hypothetical nature of science, however, but rather one that reflects the incompleteness of knowledge at any given time. It is not a product of likelihoods.

Boyle contrasted moral demonstration with the kind of reasoning found in Pascals wager argument. This argument produces a conclusion that is of less cogency than a moral demonstration that can determine our resolves, but it can still be prudent to act upon it. Wagering involves the figuring of likelihoods, and one can act rationally if all things considered, the outcome betted upon apears more likely to be true, than not to be true.84 The wager argument concerns the practical aspects of reaching a decision under uncertain circumstances. Moral demonstration, on the other hand, is achieved only in the absence of specific reasons to doubt. It seems clear, then, that on the occasions when Boyle speaks of the probable truths reached by moral demonstration, the term probable has the qualitative meaning worthy of approbation, and not todays quantitative meaning expressed by degrees of likelihood. ss Moral demonstration is compelling. If there is a concurrence of probabilities where all of the evidence is in favor of a hypothesis, then, in order to be rational, one must assent to its truth.

IV. Concluding Remarks

If the legal analogy is taken seriously, that is, if one looks to the legal domain for elucidation of the concepts employed by English experimentalists, important, but often neglected or misunderstood, aspects of the epistemological foundations of the new science become apparent. For example, since

Boyle, Cosmical Suspicions, vol. III, p. 318. Boyle, Some Considerations about Reason and Religion, vol. IV, p. 183. X41bid. See Ian Hacking, The Emergence of Probabilify (Cambridge: Cambridge University Press,

1975), esp. ch. 2, for his discussion of this dual aspect of probability. Because Hacking focuses too much upon the qualitative aspect of probability as an appeal to authority, however, he concludes that our ordinary notion of probability did not exist until the 17th century. See Patey, Probability and Literary Form, Appendix A, pp. 266-272, for a detailed criticism of Hacking. Also, see chs 1 and 2 in Patey for his alternative account that draws upon the history of probability in the law, rhetoric, and the low sciences of medicine and chemistry.


the notion of experience was much broader than that associated with sense

perception, it would be a misinterpretation of the historical texts to attribute

an empiricist position to either Bacon or Boyle. Boyle was committed to the

Baconian true and lawful marriage between the empirical and the rational

faculty.s6 He was much more cautious than Bacon in his assessment of how

soon truth would be achieved by this method, but he shared Bacons

optimism that truth would be achieved. His philosophy of science was not at

all the mitigated skepticism of philosophers such as Gassendi who advocated

an empiricist science of appearances.x7

In an extremely eclectic fashion, Boyle constructed a moderate philosophy

of science designed in such a way that it would possess the best elements from

empiricist and rationalist approaches to the study of nature. Because of this

eclecticism, it is possible to pick passages from his works that would support

either an empiricist or a rationalist interpretation of his philosophy. It is also

relatively easy to find passages that reflect the thought of earlier philos-

ophers. To the extent that predecessor studies can help to illuminate the

elements in Boyles thought, they are significant; but the temptation to

reduce Boyles philosophy to that of another, based upon a select set of

similarities, ought to be resisted. His eclecticism produced a unique

philosophy of science that ought to be evaluated in its own terms.

I have argued here for a rather strong Baconian influence upon Boyle, but

it should be stressed that while Boyle apparently followed the earlier

philosophers larger vision of science, he expanded upon and modified that

vision in its methodological details. The link between Bacon and Boyle is

significant in that it suggests that the experiential procedure of common law,

which we know to have influenced Bacons thought, also influenced Boyle.

Further there is independent evidence, in Boyles use of legal analogies, that

he was influenced by the lawyers arguments. When one then turns to the

legal tradition and its broad notion of experience, the apparent inconsistency

between the experimental way of experience and the postulation of hidden

causes actually operative in nature vanishes. Boyle rejected the metaphysical

modalities of rationalism and demanded a careful and controlled investigation

of the actual world much as an empiricist would do. But, he did not rest

content with an empiricist science of appearances. The experimental way of

Bacon, The New Organon, Preface, in The Works, vol. VIII, p. 34. Gassendis philosophy has been characterized as empiricist by Margaret J. Osler,

Providence and Divink will in Gassendis Views on Scientific KnowledgeT Journal of /he Historv of Ideas 44 (1983). 549-560; Popkin. Hisrorv of.SkeDticism; and Sarasohn, Motion and Morality. Osler claims that Gassendis mitigatedskepticism and nominalist ontology became characteristic of English science as represented in the works of Boyle and Newton. (Ibid., p. 560.)

Again. this influence is in terms of the procedures. and not the substance of the law of England.


experience was needed to correct our ordinary observations of the world. Quantitative laws linking appearances were not the end-point of his science but merely the beginning of a qualitative causal inquiry into the reasons why such regularities appeared. That is, laws became the phenomena that had to be explained in terms of hidden processes and entities operative in nature.

Twenty years ago Larry Laudan brought the decidedly non-empirical elements within Boyles work to our attention, yet the empiricist characterization of Boyle persists. The recent attempt by Shapin and Schaffer to display the socio-political origins of experimental science, for example, is seriously flawed by their failure to appreciate the complexity of Boyles method. On their account, Hobbes was right, because he recognized that knowledge was man-made and argued against Boyle and other members of the Royal Society who were involved in a game in which knowledge is, so to speak, ultimately vouched for not by human agency (individual or collective) but by reality itself .92 They argue that in our culture, saying that knowledge is artificial and conventional is tantamount to saying that it is not authentic at all, and they trace this criticism back to Boyle as the empiricist who regards the man-made component of knowledge as a distortion of the minds mirroring of reality.Y3 Because experiments are produced in the artificial environment of a laboratory, and depend upon witnessing for validation, they believe that they have shown that the experimental production of facts is fundamentally an arbitrary process that is relative to the ideological climate wherein these facts are produced.y4

As we have seen, however, Boyle not only acknowledged, but emphasized that a great amount of skill and labor is required to perform experiments. If an experiment is to be a criterion for theory acceptance, then great care has to be taken to validate the experimental results. Experimental science does not provide a foolproof method for constructing and evaluating causal theories, but it was an advance upon the Hobbesian way of reason. As Boyle said, it is

See Michael R. Gardiner, Realism and Instrumentalism in Pre-Newtonian Astronomy, in: Testing Scientific Theories, John Earman (ed.) Minnesota Studies in the Philosophy of Science X (Minneapolis: University of Minnesota Press, 1983). pp. 201-265. Gardner points out that it was the ability of the Copernican theory to yield a physical explanation of the planetary laws of motion that led Kepler to view Copernicanism realistically.

%Laudan, The Clock Metaphor and Hypotheses. Laudan is right about the non-empirical elements, but, unfortunately, once he had identified these elements, he then thought it necessary to attribute them to a Cartesian influence, and this thesis has not held up. See: G. A. J. Rogers, Descartes and the Method of English Science, Annals of Science 29 (1972), 237-255; and Sargent, Robert Boyles Baconian Inheritance.

Shapin and Schaffer, Leviathan and the Air-Pump, p. 344. Ibid., p. 150. Ibid. Their account relies uoon Richard Rortv. Philosoohv and fhe Mirror of Nature

(Princeton: Princeton UniversityPress, 1979). Richard S. Westfall, in his review of Leviathan and the Air-Pump, Philosophy of Science 54

(1987), 128-130, also finds this to be one of their central theses.


easier to undervalue experiments, than to explicate nature without them. Experimental results are decidedly man-made, but it is just this activity that makes them nonarbitrary.Yh

Shapin and Schaffer attempt to support their empiricist characterization of Boyle in part by an appeal to the testimony of his contemporaries. They note with approval, for example, that the Duchess of Newcastle attacked those for whom the bare authority of an Experimental Philosopher is sufficient . . . to decide all Controversies and to pronounce the Truth without any appeal to Reason. Similarly, they note Hobbes contention that the experimental philosophers were not interested in causal inquiry.s These remarks do not really support the empiricist interpretation of Boyle that Shapin and Schaffer have advanced. Rather, they merely indicate that, in his own day, there were those who failed to appreciate the complexity of his method. While Boyle eschewed the type of causal inquiry championed by Hobbes, namely a quantitative determination of first laws from which to deduce all other phenomena, he did not therefore reject all forms of causal inquiry. The pressure of the air, for example, was the real cause of the phenomena that had previously been attributed to natures abhorrence of a vacuum. Although Boyle could go no further - he could not offer a certain cause for the pressure of the air - this should not be regarded as causal nescience. We can know that a cause exists even if we do not know the modus of the cause:

If there be an effect, that we discern must proceed from such a cause or agent, we may conclude, that such a cause there is, though we do not particularly conceive how, or by what operation it is able to produce the acknowledged effect.

The worth of an explanation is questionable when what is to be explained

Boyle, Animadversions Upon Mr. Hobbess Problemata de Vacua. vol. IV, p. 105. (This argument has also recently been made by Kockelmans, On the Problem of Truth in

the Sciences. See also, Patey, Probability and Literary Form, p. 15, where he describes Carneades as putting forward criteria that would make assent nonarbitrary.

Shapin and Schaffer, Leviathan and the Air-Pump. p. 308. Zbid.. p. 140. Perhaps it was Hobbes close association with Gassendi that led him to misunderstand

Boyles appeal to experience. Shapin and Schaffer are attempting to follow recent work, e.g. by Latour and Woolgar, where sociologists enter the laboratory as strangers to the procedures in order to obtain what they believe to be an unbiased view [see Bruno Latour and Steve Woolgar, Laboratory Life (London: Sage. 1979)]. But because theirs is a historical laboratory, to which they cannot go directly, Shapin and Schaffer attempt to achieve the perspective of a stranger by taking Hobbes point of view. But Hobbes was not an unbiased stranger. he was an active opponent who had his own interests. one of which was to discredit the experimentalists. It is extremely unlikely that an opponent to Boyle would be a good source for what his method really was. I find Bacons dictum about knowing a man at second hand much more useful: Mens weaknesses and faults are best known from their enemies their opinions and thoughts from their familiar friends with whom they discourse most. Bacon, De Augmenris. Bk. VIII. ch. 2, in The Works. vol. IX, p. 276.

Boyle, Things Said to Transcend Reasort, vol. IV, p. 455.


has been incorrectly defined. Because Shapin and Schaffer characterize Boyles experimental philosophy as a type of empiricism, their social explanation for its success is immediately suspect. But, there are also problems associated with the content of their explanation, that result from their failure to appreciate the significance of the epistemic dimension of the legal profession, and which, in turn, have led them to oversimplify the role that legal analogies played in Boyles discourse.

According to Shapin and Schaffer, a crucial boundary was constructed around the domain of the factual, separating matters of fact from those items that might be otherwise . . . The matter of fact was offered as the foundation of proper knowledge. This is quite true. Given Boyles project, one has first to determine the effects (facts) to be explained before proceeding to speculate about their causes. Shapin and Schaffer go on, however, to present this distinction as the creation of a social boundary that was a particular concern of Restoration society:

The practices involved in the generation and justification of proper knowledge were part of the settlement and protection of a certain kind of social order. Other intellectual practices were condemned and rejected because they were judged inappropriate or dangerous to the polity that emerged in the Restoration.

But clearly, this boundary was not a new creation of the experimentalists. Boyle could easily recognize the fruitfulness of the distinction, which had a long history of use in the legal sphere, and carry it over into his experimental philosophy without thereby creating, or even using, the boundary as a solution to particular Restoration issues. lo3 Indeed, since the legal sphere was much more closely involved with political issues, and the boundary was already established in that realm, in what way would the use of it by the new experimental philosophers, who had not yet received total acceptance, serve any significant political purpose?

Another problem arises from Shapin and Schaffers analysis of the role of witnesses. They write that matters of fact were to be established by the aggregation of individuals beliefs, and that in this process a multiplication of the witnessing experience was fundamental.04 According to them, the thrust of the legal analogy consisted, in part, in the tactic of multiplying

Shapin and Schaffer, Leviathan and the Air-Pump, p. 24. Zlbid., p. 342. Bacons vision of scientific knowledge rising as a pyramid from a firm foundation of fact

would be another likely source for Boyles distinction. Obviously, Bacon was not part of the Restoration polity.

%hapin and Schaffer, Leviathan and the Air-Pump, p. 25.


authority by multiplying witnesses.5 But, as we have seen, it was not a mere multiplication of testimony, but the independence of testimony that lent weight to a fact. Since the experimental philosopher is to decide on an issue only when all of the procurable evidence is in, and the task is too large to be done alone, then of course there is a need for testimony. But facts are not merely a product of a consensus of opinion about sensory information.lOh Boyle, as always, left a large role for reason: the understanding remains still the judge, and has the power or right to examine and make use of the testimonies that are presented to it. Testimony is a matter of evidence, not of authority: Humane Authority ought not to be of force against either right Reason or Experience. a And, contrary to Shapin and Schaffers contention that the social status of a witness sustained his credibility. Boyle maintained that even of honest and sincere witnesses, the Testimony may be insufficient [if] the matters of fact require Skill in the Relator.OY

Witnessing is a much more complex process than that presented by Shapin and Schaffer. Aside from problems associated with the oversimplification of the role of witnesses, there is also a problem with their attempt to link witnessing to Restoration issues. They claim, for example, that Boyle used the provision of Clarendons 1661 Treason Act, in which, he said two witnesses were necessary to convict, as a basis for his discussion of the concurrence of probabilities. But, there is no indication that Boyle had this Act in mind - he does not cite it and he refers to a trial for murder, not treason. The two-witness rule for murder dated back to the reign of Edward VI.

Shapin and Schaffers analysis is flawed because they incorrectly characterize Boyles experimental philosophy and they tend to see the incursion of social factors as an immediate indication of political bias, without appreciat- ing that there is an epistemic dimension to these social factors. Perhaps one

/bid.. p. 56. According to them the other facet of the legal analogy involved the right action of a voluntary giving of assent to matters of fact. (p. 57.) They later tie this in with Restoration politics by characterizing Boyles probabilism as a form of liberty, where the rules of the experimental community offered this solution to the fundamental political problem of liberty and co

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