24.09 Minds and Machines an inconsistent tetrad spring 2006 1) if physicalism is true, a priori physicalism is true • more handouts 2) a priori physicalism is false shortly on website • Stoljar, contd. 3) if physicalism is false, epiphenomenalism is • evaluations, final true exam questions 4) epiphenomenalism is false

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argument for (1) argument for (2)

• out of type-A and type-B materialism, the • both the conceivability argument and the former is much more plausible than the knowledge argument show that latter “knowledge of every physical property a . see Chalmers against type-B materialism person has cannot by itself suffice to know • hence: if physicalism (materialism) is true, a which qualia, if any, his or her experiences priori physicalism (type-A materialism) is instantiate” true • hence a priori physicalism (type-A materialism) is false

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argument for (3) argument for (4)

• type-E dualism is much more plausible than • obviously qualia are causally efficacious with type-D dualism respect to physical events, otherwise we • hence if physicalism is false (and so dualism wouldn’t have any reason to think that is true), type-E dualism (and so there are any qualia epiphenomenalism) is true • hence epiphenomenalism is false

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1 (1)-(4) are individually plausible, t-physicalism and o-physicalism but at least one must be false • P is a t-physical property iff P is (i) the sort of 1) if physicalism is true, a priori physicalism property that a (true) physical theory tells us is true about or (ii) a property which metaphysically 2) a priori physicalism is false supervenes on properties that satisfy (i) • so: having +ve charge and having mass are t- 3) if physicalism is false, epiphenomenalism is physical properties (by (i): the theories of true electromagnetism/gravity) 4) epiphenomenalism is false • either having +ve charge or being green is a t- physical property (by (ii): necessarily, if x is positively charged, x is either positively charged or green) 7 8 24.09 spring 06 24.09 spring 06

a reminder from the • P is an o-physical property iff P is (i) the sort of philosophical toolkit: property required by a complete account of the nature of paradigmatic physical objects or (ii) a dispositions (powers, tendencies) property which metaphysically supervenes on properties that satisfy (i) • a special kind of property • so: having +ve charge and having mass are o- physical properties (by (i): needed for a complete • examples: fragility, solubility, elasticity account of sticks and stones) • a fragile object is (to a first approximation) • either having +ve charge or being green is an o- something that would break if it were struck physical property (by (ii): necessarily, if x is • a wine glass is fragile (has the property of positively charged, x is either positively charged fragility) even when it isn’t manifesting the kind of or green) behavior (breaking) distinctive of fragility

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something new from the philosophical toolkit: thesis 1: physical theory tells us only about categorical properties dispositional properties • (roughly) to be positively charged is to be • a special kind of property disposed to be attracted by electrons, repelled by • not a dispositional property protons, etc. • the kind of property the possession of which explains the possession of a dispositional • (roughly) to have mass is to be disposed to warp property space-time • in the case of a fragile vase, a property “whose . let’s grant thesis 1 for the sake of the argument instantiation makes it the case that the vase is fragile”

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2 thesis 2: if an object x has a dispositional conclusion from theses 1 and 2 property D, x has a categorical property C that explains why x has the dispositional property • paradigmatic physical objects have • why would this vase break when struck (i.e. why categorical properties (thesis 2) is it fragile)? • there must be an explanation, and if the • these categorical properties are not t- explanation is in terms of more dispositional physical properties (thesis 1) properties, we will need an explanation of why • but they are o-physical properties (by the the vase has these dispositional properties definition of ‘o-physical’) • so this chain of explanations must bottom out in • so, some o-physical properties are not t- an explanation in terms of categorical properties physical properties . let’s grant thesis 2 for the sake of the argument 13 14 24.09 spring 06 24.09 spring 06

back to the knowledge argument two kinds of physicalism 1 imprisoned Mary knows all the physical facts hence: • t-physicalism: everything supervenes on 2 if physicalism is true, Mary (before her release) knows all t-physical properties the facts 3 after her release, Mary learns something–something she • o-physicalism: everything supervenes on couldn’t have known while imprisoned o-physical properties 4 if Mary learns something, she learns a fact • t-physicalism implies o-physicalism, but not hence (from 3, 4): 5 Mary learns a fact conversely hence (from 2, 5): all the t-physical 6 physicalism is false facts, or all the o-physical facts? 15 16 24.09 spring 06 24.09 spring 06

…all the t-physical facts the knowledge and conceivability arguments give us reason to believe: • both the conceivability argument and the knowledge argument show that 2-t a priori t-physicalism is false “knowledge of every t-physical property a person has cannot by itself suffice to know which qualia, if any, his or her experiences but not: instantiate” • hence a priori t-physicalism is false 2-o a priori o-physicalism is false

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3 but: still an inconsistent tetrad do we have reason to believe 3-t?

3-t if t-physicalism is false, epiphenomenalism is 1-t if t-physicalism is true, a priori t- true physicalism is true 3-o if o-physicalism is false, epiphenomenalism is 2-t a priori t-physicalism is false true 3-t if t-physicalism is false, epiphenomenalism is true • no, because if t-physicalism is false, o- physicalism might yet be true 4 epiphenomenalism is false • and if o-physicalism is true, there’s no obvious reason why the mental is epiphenomenal—o- physical properties (even those that aren’t t-

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the resulting position is type-F a consistent tetrad monism (panprotopsychism) 1 if (t-/o-) physicalism is true, a priori (t- /o-) physicalism is true* • “consciousness is constituted by the [categorical] properties of fundamental physical 2-t a priori t-physicalism is false entities...phenomenal or protophenomenal [i.e. o-physical] properties are located at the 3-o if o-physicalism is false, fundamental level of physical reality” epiphenomenalism is true (Chalmers, C&IPIN) 4 epiphenomenalism is false • n.b. the nature of the protophenomenal [o- physical] properties is unknown, because *i.e. if t-physicalism is true, a priori t-physicalism is true, and if o-physicalism is true, a priori o-physicalism is true physical theory does not tell us about them

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a taxonomy of theories final exam • type-A materialism/a priori physicalism (Lewis, Dennett [apparently]) • sample quotation identification & explanation. • type-B materialism/a posteriori physicalism (Tye, Identity the authors of the following quotations. Levine) For each quotation, write a sentence or two • type-C materialism/a priori mysterianism (Nagel explaining the main point. [maybe], McGinn [maybe]) • “cut the pie any way you like, meanings just ain’t • type-D dualism/cartesian interactionism in the head!” (Descartes) • sample answer: Putnam. Putnam is saying that two • type-E dualism/epiphenomenalism (Jackson [when people who are intrinsically just alike (that is, who he wrote “epiphenomenal qualia”]) are molecule-for-molecule replicas) might mean • type-F monism/panprotopsychism (Chalmers, different things by their words. Stoljar) 23 24 24.09 spring 06 24.09 spring 06

4 • “Such in outline is the official theory. I shall speak • sample multiple choice: of it, with deliberate abusiveness, as ‘the dogma of • 1. Is Ned Block's example of the Aunt Bubbles the Ghost in the Machine’. It is one big mistake machine supposed to refute functionalism? and a mistake of a special kind. It is, namely, a category-mistake.” • 2. Does Searle think that strong AI is false? • sample answer: Ryle. What Ryle calls the “official • sample short answer (a paragraph): theory” is the dualism of Descartes. An example • 1. What is behaviorism? Describe one objection of a category mistake is this: thinking that MIT is to behaviorism that we discussed in class. just another building on campus, like the Stata Center, Kresge Auditorium, etc.

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essay questions (answer 2 out of 3) • 2. In “Consciousness and its place in nature”, Chalmers distinguishes Type-A Materialism, Type- • 1. Nagel, Jackson, and McGinn all think that B Materialism, Type-C Materialism, Type-D consciousness poses a problem for Dualism, Type-E Dualism, and Type-F Monism. physicalism, on somewhat similar grounds. Pick one that you think is false. Explain what this Critically compare and contrast their views. theory is, and why you think it’s false. Now take the theory that you think is true (or, at any rate, Is it true that “with consciousness, [the is the least implausible of the lot). Explain what mind-body problem] seems hopeless”? this theory is, and defend it against objections.

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Minds and Machines • 3. Could a suitably fancy robot think? More specifically, spring 2006 could a robot believe that it’s raining in Cambridge? (Take the robot to be constructed from the usual materials: microprocessors, cables, servomotors, etc., with a variety . more on the final of external sensors like cameras and microphones.) Could a suitably fancy robot have conscious experiences? More exam next time specifically, could a robot feel pain, or have a yellowy- . questions on web orange afterimage? Approach these questions by considering how they might be answered by various by wednesday philosophers we have encountered, for instance . read McGinn Descartes, Smart, Block, Lewis, Putnam, Dennett, and Chalmers.

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