Define 'physical': problems with defining the physical in physicalism (Msimang 2015 PSSA presentation)

Define ‘physical’: Problems with defining ‘the physical’ in physicalism

PHILA MFUNDO MSIMANG

UNIVERSITY OF KWAZULU NATAL

PSSA PRESENTATION, JANUARY 2015

Contents

Nuanced theory of the universe. Its basic claim is that everything is physical. Some interpretations of this are:• everything is physically instantiated or caused• everything is physically composed• there are only, at the fundamental level, physical forces• Etc.

What is physicalism?

Physicalism is said to make strong or weakmetaphysical claims depending on itsformulation. All modern versions of physicalismare unified by theses claiming the ontologicalfundamentality of the physical. © Joyner 2012

Contemporary relevance

• Although physicalism has historical connections to the Unity of Science movement of the VCLP, it is not a theory about methodology but is rather a metaphysical theory---specifically, about fundamental ontology.

• “Contemporary physicalism is an ontological claim rather than a methodological doctrine. It claims that everything is physically constituted, not that everything should be studied by the methods used by the physical sciences” (Papineau 2001, p. 3).

• If physicalism was reductionist, then the methodological thesis would follow. But physicalism is varied in the relationship it claims between physics and other domains.

• Physicalism is part of the popular debate in the philosophy of mind, with some of its arguments centring around whether or not mental content is in some way supervenient on physical states or has some other kind of physical dependence or causal relationship with the physical.

• Physicalism is connected to the justification of fields such as neuropsychology and cognitive science in so far as they claim to explain human behavior and the underlying biological mechanisms which are said to cause or afford behaviors.

“Every era has its Weltanschauung and in much contemporary philosophy the doctrine of physicalism plays this role.” (Gillett and Loewer 2001: ix)

“Weltanschauung is, I am afraid, a specifically German concept, the translation of whichinto other languages might well raise difficulties. If I try to give you a definition of it, it isbound to seem clumsy to you. In my opinion, then, a Weltanschauung is an intellectualconstruction which solves all the problems of our existence uniformly on the basis of oneoverriding hypothesis, which accordingly, leaves no question unanswered and in whicheverything that interests us finds its fixed place. It will easily be understood that thepossession of a Weltanschauung of this kind is among the ideal wishes of human beings.”

(Freud 1995: 783)

The opening quotes in Daniel Stoljar’s recent book on physicalism suggest the prominence of the physicalist debate in contemporary philosophy. These are reproduced below:

The ‘catch-phrase’: physicalism as a bumper sticker

• The physicalist catch-phrase, which is also its basic claim –“everything is physical” – can guide us in understanding all of the different kinds of physicalism.

• The physicalist catch-phrase does not represent any specific theory but, rather, it is a schemata for different theories satisfied by different characterizations of the phrase.

• Defining each one of the terms within the catch-phrase puts into context and delineates the range and limits of the claims being made.

“Everything is physical”

What is the scope of “everything”?• Sounds• Mentality• Phenomenal content• Numbers?• Universals?

What is the relation that “is” represents?• Supervenience• Reduction• Emergence?• Some other kind of dependence?

What is the “physical”?• An a posterior category or class• An a priori category or class• A highbred metaphysical notion• The content of physical science

simpliciter• Whatever can be explained?

What is the specification question?

• It is a part of the general formulation of the physicalist thesis.• Its concern is with the question “What is the physical?”.• The answer to this question is central to the thesis of physicalism because it

gives content to physicalism.• The specification question is thus a central question to be answered by

physicalists.• The standard way the specification question has been answered in

contemporary philosophy is by a direct appeal to physics.

• He argued that if it is present physics that was being appealed to, ‘current physics’, then the specification from it will have the same inherent problems as the physics of the day; and if it were a future physics being appealed to for specification, we would not know what it says in the same way we have no idea what future physics holds.

• This two-pronged problem was thus called Hempel’s Dilemma, and was extended from his original insights. Carl Hempel

• Carl Hempel noted that there is a problem with such answers to the specification question.

• He asked which physics, in particular, was being appealed to when the specification of the physical was being given.

Hempel’s Dilemma: choosing which physics?

The first horn: current physics The second horn: future ideal physics

• Future physics more accurate• Future physics ideal• Future physics true• Future physics presently unknown• Future physics indeterminate• Future physics makes physicalism trivially true

[under Chomsky’s interpretation]

• Present physics determinate• Present physics approximate• Present physics inaccurate• Present physics incomplete• Present physics inconsistent• Present physics ‘obviously’

[logically?] false

Specifying physics for the physical of physicalism

© Carroll 2013

First horn – current physics (part 1)General issues

• Interesting characteristics of the current physics option are that it has determinate content, and a content we have a particular confidence in.

• These characteristics have pros and cons: the determinate content we have is problematic in so far as it is incomplete and inconsistent, and the confidence we have can be shaken by the fact that all previous physical theories we have had have been false or inaccurate.

• Each of these arguments can be taken as independent concerns (e.g. pessimism).

• “To say that current physics is incomplete,” for instance, “is not to say that it is mistaken in any specific suggestion it makes about which properties and relations are required in the explanation of ordinary physical objects and related phenomena” (Stoljar 2010, p. 98).

• The concerns against the current physics option are unified by the idea that the problems in present physics reflect problems in the ‘current physics’ option.

• The strength of the current physics option is that the physicalism built upon it is said to reflect all the successes of present day physics.

First horn – current physics (part 2)Andrew Melnyk (1997)

• Andrew Melnyk (1997) made a strong case for taking on the current horn of the dilemma, but starts by laying the groundwork for the case of physicalism in general.

• He argued that we should take physicalism as a scientific hypothesis---even if we do not believe it is one, he argued that it is like one in all relevant respects and should be treated as such.

• This is his grounding for the argument that since it is the best hypothesis of the universe we have, that we should pursue and develop it.

Is the thesis of physicalism even making the same claims

as physics? Is physicalism philosophical or is it scientific? Is there sense in it being both?

• A loose and crude summary of the argument: What is this ‘best hypothesis’ of the world we already have? Physics. Which physics is this? It can only be current physics.

• A more sophisticated motivation he gives is based on criteria that physicalism must meet.

• The most important of these reasons is that physicalism must have determinate content---i.e., content known by us---and not be obviously or irredeemably false (although it must, presumably, be falsifiable).

First horn – current physics (part 3)Overcoming or accepting?

• “if current physics is not true, but only approximately true, then… some future physics will do a better job of characterizing these entities – that is, will be more approximately true. Hence, there is effectively no motivation for the physicalist to characterize the base set in their foundationalist ontological thesis as only adverting to current physics. Even if current physics is approximately true, reference to future (and in the supposed limit of inquiry, ideal) physics is needed in recognition of the fact that current physics hasn’t yet gotten it entirely right” (Wilson 2006, pp. 66–67).

• Current physics is either a thesis containing its own redundancy and reasons for abandonment, or it is a work in progress which will only be completed at the end of the scientific inquiry of the physical.

• The first option is devastating for currentism, but the second option is just but another way of expressing that the answer to the specification of the physical in physicalism would be deferred to the consequences of some future physics.

Wait a second… Would we have

to go back to the future?

Second horn – future/ideal physics (part 1)General issues

• This is a challenge to any specification of the physical based on a future or an ideal physics.

• Future physics is assumed to be epistemically better off because of optimistic belief in the progress of physics.

• Pessimistic sentiments can also be had about future physics.• The optimistic and pessimistic options are a battle of the

intuitions that can only be settled by the coming of future physics. Future physics would have to become present-day physics in order for us to decide on the matter.

Second horn – future/ideal physics (part 2)Wilson (2006); Stoljar (2010); Chomsky (2000)

• Wilson says that “On one reading, the worry is that a physicalism based (only) on future (ideal) physics does not have determinate content, since we don’t know what entities future (ideal) physics will treat” and that “On another reading, the worry is that such a lack of determinate content will render physicalism trivially true” (Wilson 2006, p. 67).

• “Suppose then we don’t know what physicalism says—what follows? Well, if we do not understand it at all, we are in no position to know it, no position to deny it, no position to believe or disbelieve it with justification. Nor are we even in a position to speculate about whether it is true. In fact the whole project of rationally assessing physicalism—providing reasons for and against it, declaring oneself for it or against it, saying it is a good bet at least in the long run—seems to presuppose that we know what it is, at least in outline. But if that presupposition is false, physicalism is unworthy of assessment” (Stoljar 2010, p. 100).

• “We can, however, be fairly sure that there will be a physical explanation for the phenomena in question, if they can be explained at all, for an uninteresting terminological reason, namely that the concept of physical explanation will no doubt be extended to incorporate whatever is discovered in this domain, exactly as it was extended to accommodate gravitational and electromagnetic force, massless particles, and numerous other entities and processes that would have offended the common sense of earlier generations” (Chomsky 2000).

Second horn – future/ideal physics (part 3)Overcoming or accepting?

• The concern of physicalism being trivially true rests on a loose understanding of physicality.

• Chomsky (2000) says the physical is anything that can be explained even if the explanans are known to be non-physical explanans. (Chomsky would categorize them as physical because they explain.)

• That Chomsky’s criticism is taken seriously reveals a weakness of the lack of generality over what are considered satisfactory answers to the specification question. Such worries should be ruled out on principle otherwise there would be no meaning to the thesis of physicalism (cf. Stoljar 2010).

Some thinkers don’t take Chomsky’s extension of

the second horn of Hempel’s Dilemma

seriously.

• The ‘no fundamental mentality’ constraint (Wilson 2006) or the via negativa approach (Spurrett & Papineau 1999) can be seen to accept the dilemma in so far as it does not claim to know the content of future physics.

• These two approaches (NFM & VN) do not leave the content of physicalism completely indeterminate or the concept of the physical absolutely open since they reject the possibility of fundamental mentality.

• Is this an overcoming of Hempel’s Dilemma, or an acceptance of it as a non-fatal criticism of the future and ideal physics option?

• What is specified by the negative? Logical illustration makes it clearer. • Say {x} is ‘the physical’ and *{m} is ‘not mental’. The set of *{m} things

is not the same as {x}; *{m} is equivalent to {x, y, z…}. • All we want is {x}, the physical, and none of the other categories of

*{m}≡{x, y, z…} for the purpose of the specification of the physical.• Even if the no fundamental mentality constraint and the via negativa

approach are said to overcome Hempel’s Dilemma, I argue that they do not sufficiently answer the specification question because the NFMconstraint & VN approach are not specific enough to specify the physical, thereby not satisfying the specification question.

The recurrent problem for currentism

• What is the meaning of new discoveries for physicalism in context of dilemma?• Increased epistemic justification (on an optimistic reading) but current

physics challenge never settled.• Physical discovery re-opens physical theory to currentist challenges

through new specifications of the physical.

Discovery of empirical

thing

Classification as physical

thing

Inclusion in specification of physical

Current horn of Hempel’s

Dilemma

Overcoming / acceptance of dilemma1. Empirical discovery

2. Classification as physical3. Inclusion into physical theory4. Questions of viability5. Resolution of questions

Recurrence or the vicious cycle

1.

2.

3.

4.

5.

∞

• Hempel’s Dilemma is never answered once and for all in this arrangement.• Whether or not current physics can overcome the dilemma is irrelevant to

the fact that it will recur with each new development in physics. • The recurrence of this issue could only be resolved at the end of scientific

inquiry of the physical because that would be the only time no new discoveries would be made to revitalize the question of Hempel’s Dilemma.

• “[T]he appeal to future physics is inspired by the fact that current physics is to some extent inaccurate and/or incomplete; but similar considerations would apply to any version of future physics antecedent to ideal physics” (Wilson 2006, p. 71).

• Only a final physics can dissolve the vicious cycle in the specification of the physical for physicalism because that would be the last physical theory it would be possible to specify.

Is there generality in specification?

• Both the currentist and futurist positions work on the assumption that physicalism is what a true or approximately true physics of a particular world says it is (Stoljar 2010, p. 107)

• This leaves out the fact that there are other ways which the world could be which would satisfy physicalism even though we may know these physical theories to be false.

• Physicalism does not have to be true, and there are formulations of it which are false.

• I argue that there must be something that these ‘different’-seeming ‘physicalisms’ share.

Democritus, father of atomism

• There are multiple physical theories that satisfy the specification question.

• Some examples are pre-established harmony or Cartesian dualism without the interactionism, Newtonian mechanics, Hobbes’ physical theory, Democritus’ atomism, etc.

• Could the generality come from a particularunderstanding of physicality that is not connected toany specific physical theory, but which is the categoryto which all physical theories belong?

• If yes, what is this criterion of satisfaction?

Considering the diversity of physicalist theories, how is it that they relate to one another?

Is this relation made by a generalization over all possible answers of the specification question?

A way forward

• Questioning the question---viz., the validity of the dilemma (e.g., Stoljar).• A more flexible notion of the physical, not attached to any specific

physics.• Similar suggestions have been made by proposing a metaphysical notion

of the physical for specification which is informed or “honed” by physics(c.f. Crook & Gillett 2001; Wilson 2006).• The resulting physicalism can be proven false by any instance of non-

physical instantiation/cause.• A focus on specification irrespective of the effectiveness of the dilemma?

• We cannot draw our definition of the physical from current physics withouthaving an obviously incorrect definition of the physical.

• Strategies of specification based on a true physical theory for physicalismare wanting for their lack of generality over other satisfactory but falsespecifications of the physical. (Newtonian physics; the physical side of pre-established harmony, Hobbe’s mechanistic view, etc.).

• Without a systematic idea of the relevant progress of an already existingidea of the physical, changes in physics reawaken the challenge ofHempel’s Dilemma for any specification of the physical.

Main points: recapitulation

• We cannot draw our definition of the physical from future physicsbecause we do not know what future physics contains. (The lacking offuture and ideal specifications)

• Future physics can contain anything if there isn’t a systematic way torestrict the notion of the physical---a problem outlined by the lack ofgenerality over what counts as satisfactory answers to the specificationquestion and a challenge that was anticipated by the via negativa or nofundamental mentality approaches which are, themselves, responses tothe worry of the unsystematic expansion of the physical. (A challengestill to be overcome satisfactorily for the viability of a specification of thephysical).

• The specification of the physical as physics (as opposed to being basedon physics, for instance) causes problems for the specification of thephysical for physicalism.

We have come to the end of the

presentation “Problems with

defining ‘the physical’ in physicalism”

Comments and queries are welcome!

Phila M. MsimangUKZN, 2015

© N/ACC-BY