Summer 2011 Thursday, 07/07 Loose Ends: Wittgenstein’s Beetle • Each of us carries a box with something that each of us calls a beetle. • We can only look inside our own boxes, not anyone else’s box. • How, then, can I know that what I’m calling beetle is the same type of thing as what you’re calling beetle? Maybe your box has something completely different… Loose Ends: Wittgenstein’s Beetle • Similarly, for the Dualist, each of us has a mind that sometimes contains something that each of us calls pain. • We can only look inside our own minds, not anyone else’s minds. • How, then, can I know that what I’m calling pain is the same type of thing as what you’re calling pain? Maybe your mind has something completely different in it and we’re using the same word to talk about radically different things. • This problem does not arise for the behaviorist. Philosophical Methodology • Concepts = Ways of Thinking, General Ideas. • Some concepts have analyses or definitions, E.g, Vixen =def Female Fox Bachelor =def Unmarried Adult Male Opthomologist=def Doctor who specializes in eyes Philosophical Methodology • Some (putative) analyses or definitions are Philosophically important, e.g, Knowledge=def Rational True Belief Moral Action=def Action That Maximizes Collective Pleasure. • Sometimes it’s difficult to come up with a complete analysis or definition of a concept and only partial or incomplete definitions may be available. Philosophical Methodology • An Analytic Claim is (roughly) one that’s true by definition: it is a claim that either (a) articulates a definition or (b) one that follows from a definition, e.g, Opthomologists are Doctors Bachelors are males Philosophical Methodology Analytic claims are true by logical necessity, which is the strongest of all forms of necessity (stronger even than physical necessity). • A claim is logically necessary just in case it is true in all conceivable or imaginable situations (or logically possible worlds). • Contrast: a claim is physically necessary (or necessary, given the Laws of Physics) just in case it is true in all physically possible worlds. • Philosophical Methodology • Let’s look at an example. • The simplest way of creating a concept is by explicitly defining it, e.g, BLUP =def Any person who is enrolled in Eli’s Minds and Machines Course this term. Philosophical Methodology • Now consider some claims that follow from this definition: 1. All BLUPs are enrolled in Eli’s Minds and Machines course this term. 2. All BLUPs are persons. • Since these claims follow from the definition of BLUP, denying them would not just be false, it would be nonsense. There is no conceivable situation where the negation of these claims would be true. Philosophical Methodology We can thus say: 1. Necessarily, all BLUPs are enrolled in Eli’s Minds and Machines course this term. 2. Necessarily, all BLUPs are persons. Contrast this with: 3. Necessarily, nothing travels faster than the speed of light. 4. Necessarily, gravity attracts us to the earth. 3 and 4 involve claims that are true in all physically possible scenarios. 1 and 2 involve claims that are true in all conceivable scenarios, or are true in all scenarios period. Philosophical Methodology • I’ve said that if a claim is a definition (or is true by definition), then it is true in all conceivable cases or scenarios. • So: if we find at least one conceivable or imaginable scenario where the claim is false, then the claim does not articulate a definition (nor does it follow from one). • This method is parallel to the one used in physics, math… Philosophy and Science Fiction • We can now see how remote science fiction scenarios can help refute Philosophical claims. • The Logical Behaviorist says: Pain =def A pattern of actual/potential behavior that involves wincing, making certain reports, etc. Putnam argues that there are conceivable scenarios where this claim is false (e.g. Super-Spartans, Xworlders). If Putnam is right, then the above claim is not true by definition: our concept of pain is not that of a certain pattern of behavior. So logical Behaviorism is false. Identity Theory vs. Behaviorism • Behaviorism: Mental States =def Patterns of Actual/Potential Behavior. • Putnam’s Thesis: Mental States =def Whatever Causes our patterns of Actual/Potential Behavior. (notice that this is compatible with Dualism!) • Identity Theory: Mental States =met States/Processes in the Brain. Identity Theory vs. Behaviorism • Since the logical behaviorist is making a claim about our concepts or ways of thinking, it is important that the behavior she appeals to is overt and publicly observable. • Brain states/processes cannot be instances of behavior (in the behaviorist’s sense), since it’s implausible that we think about them when we think and talk about mental states. Identity Theory vs. Behaviorism • The identity theorist does not claim that our concepts of mental states/processes are concepts of brain states/processes. • Rather, she makes a claim about the relation between the mental and the physical items themselves. • Compare: our concepts of water/light/weight vs. what water/light/weight really are. Two theses about the mind-brain relation • Mind-Brain Correlation Thesis: For each type M of mental event that occurs to an organism o, there exist a brain state of kind B (M’s “neural correlate” or “substrate”) such that M occurs to o at time t if and only if B occurs to o at t. Two theses about the mind-brain relation Some motivation for the correlation thesis: • brain lesions are correlated with changes in mental states – strokes – brain injuries – concussions • chemical changes in the brain are correlated with changes in mental states – – – – – caffeine alcohol Hallucinagenic drugs (e.g. LSD) anesthesia Opiates Two theses about the mind-brain relation • Mind-Brain Identity Thesis: There are no mental events over and above, or in addition to, the neural processes in the brain. Mental event types are identical to types of brain events, e.g. pain = C-fiber firing, belief that snow is white = cortical configuration X. • Notice that the second thesis implies the first (and explains it), but not vice versa. Arguments for the identity theory Occam’s razor: Advocates theoretical simplicity. I. Entities must not be multiplied beyond necessity. II. What can be done with fewer assumptions should not be done with more. • Most of what we know of consists of some arrangement of physical stuff. To suppose the mind to be nonphysical would be to admit a completely new type of entity. So it would be a gain in simplicity to identify mental processes with physical processes. Arguments for the identity theory Scientific Precedent: • gene =def. occupant of such and such a causal role, i.e., the role of "an internal factor in the organism that is causally responsible for the transmission of heritable characteristics." • We find that DNA molecules are what perform that causal role. • Conclusion: genes = DNA molecules. • Analogous situation: pain =def. effect of bodily damage & cause of pain-behavior • neurophysiology reveals C-fiber activation occupies this role. • Conclusion: pain = C-fiber activation. Arguments for the identity theory Mental Causation: We discover that some brain-state (e.g. C-fiber activation) causes pain-behavior. If pain ≠ C-fiber activation, then either: A. Overdetermination: unlikely. B. Epiphenomenalism: implausible. So, pain = C-fiber activation. Leibniz’s Law of Numerical Identity The Indiscernibility of Identicals: If X is identical with Y, X and Y have all their properties in common -- that is, for any property P, either both X and Y have P (at time t) or both lack it (at t). Leibniz’s Law of Numerical Identity Applications in Arguments: X is P Y is not P Conclusion: X ≠ Y • Example – Eli lives in Brooklyn. – Obama does not live in Brooklyn. – Conclusion: Eli is not Obama. Using LL to argue against the identity theory - Pain has the property of being known to Aristotle. - C-fiber activation lacks the property of being known to Aristotle. - Pain ≠ C-fiber activation. Using LL to argue against the identity theory - physical property instances (e.g., c-fiber activations) have spatial locations. - mental property instances (e.g., pains) have no spatial locations. - Mental property instances (e.g., pains) ≠ physical property instances (e.g., c-fiber activations). Using LL to argue against the identity theory - physical property instances (e.g. activation of the visual cortex) have no experiential properties (e.g. a yellowish feel). - mental property instances (e.g. color experiences) have experiential properties (e.g. a yellowish feel). - mental properties (e.g., color experiences) ≠ physical properties (e.g., activation of the visual cortex) Multiple Realization Argument against the identity theory - The identity theorist says that pain is C-fiber excitation. - But that implies that unless an organism has C-fibers, it cannot have pain. - But how can we be sure that all pain-capable animals have C-fibers? Could there not be intelligent extraterrestrial creatures with a complex mental life but whose biology is not even carbon based? Quiz • What is the Mind-Brain Identity Theory and how is it different from Logical Behaviorism? For Monday • We’ll talk about Functionalism, a completely different way of looking at the mind, that takes the multiple realization argument very seriously. • Read Chapter 1 of the Yellow Book. • Turing’s article “Computing Machinery and Intelligence” is highly recommended.