Intro to Philosophy Review for Exam 3
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Intro to Philosophy
Review for Exam 3
Philosophy of Mind
• Are there minds? • What is the nature of mind and consciousness? – Is the mind material? – Is the mind immaterial? – Am I just a brain or something more?
Basic Terminology • Substance = A basic thing which underlies change.
– X is red, X is 5 pounds, X is 8 by 2.25 inches, X is clay etc… • Whatever x is, it will be a substance. In this case it is a brick. • Informally, it is a basic kind of “stuff.”
• Property = A quality/characteristic that is possessed by or true of substances (e.g. redness, weight, size etc…) – Essential Property = A quality/characteristic that a substance has
such that if it were not there, then the substance would not exist (e.g. for a brick, the property of being physically extended would be essential).
– Accidental Property = A quality/characteristic that a substance has such that if it were not there, then the substance would still exist (e.g. for a brick, the property of being red would be accidental).
Substance Dualism (Descartes & Locke) • The view that there are two kinds of basic stuff –
material substances, and immaterial substances. • I am = an immaterial substance (i.e. a mind/soul). • I have/own a material substance (i.e. a body)
But why think that substance dualism is true?
• Descartes gives two arguments for substance dualism.
• Both of them depend upon Leibniz’ Law.
Leibniz’ Law
• If A and B are the same thing, then they will have all of the same properties.
• Suppose we are wondering if A and B are really the same thing.
• Suppose further that we know that A is 3 ft tall but that B is 7 ft tall. – It follows that A ≠ B.
The First Argument
• 1) I can conceive of myself without this body. – Whether it is a different body or no body at all.
• 2) I cannot conceive of myself without a mind. • 3) Thus something is true of the body that is
not true of the mind. • 4) Things that have different properties cannot
be identical. (i.e. Leibniz’ Law) • 5) Therefore, the body and mind are not
identical.
The Second Argument • 1) Minds are essentially indivisible. – Even though I have different mental faculties, I am the
one who underlies all of these faculties. • 2) Bodies are essentially divisible. – Since bodies are extended in space, their spatial nature
allows them to be divided into parts. • 3) Thus something is true of the body that is not
true of the mind. • 4) Things that have different properties cannot be
identical. (i.e. Leibniz’ Law) • 5) Therefore, mind and body are not identical.
Substance Dualism: The Relationship Between Brain Events and Mental
Events.
Peter Carruthers and the Mind/Brain Identity Theory
• “Even if descriptions of conscious experiences are logically independent of all descriptions of physical states (as the [C]artesian conception implies) it may in fact be the case that those descriptions are descriptions of the very same things. This is just what the thesis of mind/brain identity affirms.” – p. 327
The Identity Theory: The Relationship Between Brain Events
and Mental Events.
But why think that the identity theory is true rather than Descartes’ substance
dualism? • Carruthers counters Descartes’ arguments by saying
that they are not an appropriate use of Leibniz’ Law. • Cartesian arguments tend to confuse the following
distinct notions: – If A and B have different properties, then A and B are not
identical. (Leibniz’ actual law) – If I am certain that A has properties but am not certain that
B has those same properties, then A and B are not identical. • Descartes’ arguments need the first of these but instead
utilize the second. Thus Descartes’ arguments are about himself rather than A or B!
A counterexample to Descartes • 1) I am certain that Bruce Wayne is a billionaire and am
uncertain as to whether or not he spends his free time fighting crime.
• 2) I am certain that Batman spends his free time fighting crime and am uncertain as to whether or not he is a billionaire.
• 3) But then Batman and Bruce Wayne have different properties.
• 4) Things with different properties are not identical. • 5) Thus Batman and Bruce Wayne are not identical.
Carruthers’ Argument for the Identity Theory.
• Substance dualism has a major problem – namely, the causal interaction problem.
• Since immaterial substances couldn’t causally interact with material substances, we should just do away with immaterial substances altogether.
• Material substances can causally interact with other material substances.
• Moreover, mental states play an important role in what we do physically (i.e. our physical states).
Carruthers’ Argument for the Identity Theory.
• 1) Some mental states are causally necessary for the occurrence of some physical ones. – i.e., feeling thirsty is necessary for going and consuming
H20. • 2) In a completed neuro-physiological science there
will be no need to advert to anything other than physical-physical causality. – i.e., one day our science will be sophisticated enough be
able to explain everything with physical-physical causality. • 3) Therefore, some mental states are identical with
physical brain states and events.
Carruthers’ Modest Conclusion • Why should we be satisfied with the conclusion that
only some mental states are identical to physical states? • Think of Carruthers’ tactic as a Trojan horse. – Once the physicalist’s foot is in the door, then there is no
reason to open the door wide open! • Imagine how unprincipled it would be to say that my
mental state of being happy is a purely physical event, but that my mental state of being sad is purely (and irreducibly) mental!
• Once we say that some mental states are purely physical, then the best explanation would be to say that they all are.
To sum up the thought process for identity theorists…
• Identity theorists acknowledge that mental states exist.
• Since they acknowledge that mental states exist, then they need to explain their existence.
• They do so by saying that mental states are identical to brain states (hence the name…).
Michael Graziano and the theory of Eliminative Materialism.
• “Many theories have been proposed [to account for inner mental states], but none has passed scientific muster. I believe a major change in our perspective on consciousness may be necessary, a shift from a credulous and egocentric viewpoint to a skeptical and slightly disconcerting one: namely, that we don’t actually have inner feelings in the way most of us think we do.”
Eliminative Materialism: The Relationship Between Brain Events
and Mental Events.
Eliminative Materialism vs. Identity Theory
• Identity Theory: “mental states exist and need to be accounted for.”
• Eliminative Materialism: “mental states don’t
exist any more than ghosts or centaurs do and thus do not even need to be accounted for.”
Interesting questions to ask…
• If Eliminative Materialism posits that there are no mental states, then how is it that we can even think about whether or not Eliminative Materialism is true or false to begin with?!
• Note that Graziano himself says things like… – “I believe a major change in our perspective on
consciousness may be necessary… • This is not to say that Graziano can’t say
anything in response to this kind of objection. But it is important to think about none-the-less.
Substance Dualism and Substance Monism
• Substance Dualists – Descartes and Locke • Substance Monists – Peter Carruthers and
Michael Graziano. (Both are physicalists) – What is Physicalism?
Physicalism
l The view that everything can be explained, in principle, by a physical theory of sorts. (Think something like the science of physics)
l Physicalism is not the same thing as materialism.
l What is the difference between physicalism and materialism?
Epiphenomenalism
l The view that there exist qualia, which are caused by physical states, but not do themselves cause anything.
l Qualia are not identical with brain states. l Stands in opposition to Physicalism
Why opposition?
l Physicalism is the view that everything that is true can be explained in terms of the science of physics. That is to say, a person with complete knowledge of the the nature and functioning of the physical world could still not know what it is like to experience redness.
l Qualia are things that cannot, according to Jackson, be explained in terms of physics.
l This is because Qualia are necessarily subjective in nature, so they cannot be explained adequately by an objective scientific theory.
Frank Jackson l “I am what is sometimes
known as a "qualia freak". I think that there are certain features of bodily sensations especially, but also of certain perceptual experiences, which no amount of purely physical information includes. Tell me everything physical there is to tell about what is going on in a living brain... you won't have told me about the hurtfulness of pains, the itchiness of itches, pangs of jealousy....”
Qualia l The felt quality of a conscious experience. l Directly known to us by means of first-person experience l It 'feels' a certain way to have various kinds of conscious
experiences. Pain feels a certain way. Certain foods have a particular taste. A scented has a certain, distinct smell.
l According to Jackson, Qualia have no causal power at all in the physical world. He refers to Qualia as an excrescence.
l Given qualia, Frank Jackson claims that epiphenomenalism is the only alternative to Dualism.
So, which of the following would not be a kind of qualia?
l What the redness of a rose is like. l How the sweetness of sugar tastes. l The felt warmth of a blanket. l The biological events causing reaction to
injury. l The felt Coldness on a Winter night.
Epiphenomenalism: The Relationship Between Brain Events and Mental
Events.
Alan Turing (1912-1954) l Mathematician, Logician, and Philosopher l Was concerned with questions about determining how we
can tell if something can think l Ultimately sought to provide a method we could use to test/
determine whether a thing was a thinking thing or not. l Was not convinced that only things with a brain could think. l Was particularly interested in computers because computers
force us to consider how we discern what things have conscious states and which do not.
The Turing Test
l The best test to determine whether or not we count something as thinking is to compare its behavior to the behavior of paradigm cases of thinking things (like humans).
l That is to say its actions (such as responses to questions) are nearly identical or at least very similar to a human being's.
Turing Test Setup
l Place one person (the interrogator) in a room on a computer. In two other rooms, have one with a computer program and the other with a person. The interrogator asks questions, to which the person and the computer give responses. According to Turing, a thing can be said to be thinking only if the interrogator cannot tell which response comes from the computer and which from the person.
l This, Turing says, will eliminate certain kinds of biases, such as those based on the physical appearance of the subject in question.
The Argument from Consciousness
l An Objection to the Turing test. l Only Conscious things think. Computers are
not conscious. Therefore, Computers do not think.
Turing's responses
l How do we know computers aren't conscious? That seems to be the question we are trying to answer.
l The argument begs the question. It assumes the point it is trying to prove.
A Summary of the Views
One more thing…
Good luck!
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