2015.10.21 Descartes, Substance Dualism
Table of contents 1 The Argument, first pass 2 Conceivabilitiy and Possibility 3 Leibniz s Law
Substance Dualism Substance Dualism There are two fundamentally different sorts of things in the world: minds and bodies. (why would you think this?) Usually people reject dualism by accepting some form of identity theory: Identity Theory Minds are identical to material objects. For example: your mind is your brain (or perhaps your brain + CNS, etc.). Identity: your mind and your brain (or whatever) are identical. They are the same thing. They are one thing (with two names).
The Argument 1 If I can clearly and distinctly conceive of something, then God can create it. (God is omnipotent....) 2 I can clearly and distinctly conceive of my mind being without a body. 3 God could have created my mind without my body. 4 So my mind has a property my body does not have: (what s a property?) My mind has the property: could have been created by God without my body existing. My body does not have this property, though. 5 If x is the same thing as y, then x and y have all the same properties. 6 My mind and body are not the same thing. Hagemann s Objection: atheism
Amended Argument 1 If I can clearly and distinctly conceive of something, then it is possible. 2 I can clearly and distinctly conceive of my mind being without a body. 3 It is possible that my mind exist without my body. 4 So my mind has a property my body does not have: My mind has the property: could exist without my body existing. My body does not have this property, though. 5 If x is the same thing as y, then x and y have all the same properties. 6 My mind and body are two different things. A Godless argument!
Table of contents 1 The Argument, first pass 2 Conceivabilitiy and Possibility 3 Leibniz s Law
Premise 1 If I can clearly and distinctly conceive of something, then it is possible. Counterexamples?...
Archer Cartesian response: distinguish character of representation and what is represented
God damn it Brett
Impossible Objects
Math and Logic Goldbach s Conjecture: Every even integer greater than 2 can be expressed as the sum of two primes. Can you conceive of it being true? Can you conceive of its being false? We tend to think mathematical and logical truths are necessarily true. (why?)
Discovering Essences Water is essentially H 2 O: that is what it is to be water. Can you imagine that it was otherwise? I m sure people could imagine it was all sorts of things before chemists discovered it is in fact H 2 O.
Discovering Identities Lois Lane could conceive of Superman not being Clark Kent. But is it possible that Clark Kent is not Superman? Here s a quick argument: It s necessary that Clark Kent is Clark Kent. So Clark Kent has the property: necessarily being Clark Kent. Superman is Clark Kent, so Superman has all the same properties as Clark Kent. So Superman has the property: necessarily being Clark Kent. That means: it is necessary that Superman is Clark Kent.
Putting the examples together... Worry: conceivability is about what is compatible with what we know, maybe even what we know vividly, not what is possible. Cartesian response: you only think you re conceiving in those cases....
Putting the examples together... cont. But then premise 2 I can clearly and distinctly conceive of my mind being without a body. looks much less obvious. On this way of thinking about things, we could discover that we weren t really conceiving of this at all (say, by doing biology). Cartesian response: how else can you tell what is possible? Answer: :( Okay, there is perhaps some important link between conceivability and possibility. But what is it, and will it allow us to replace (1) with something else that will work? It s an open question....
Table of contents 1 The Argument, first pass 2 Conceivabilitiy and Possibility 3 Leibniz s Law
Premise 5 Leibniz s Law If x is the same thing as y, then x and y have all the same properties.
Statue and Clay Imagine a statue made of clay.... 1 It is possible that the statue stop existing while the clay keeps existing. 2 So: the statue has the property: could stop existing while the clay keeps existing. 3 It is not possible that the clay stop existing while the clay keeps existing. 4 So: the clay does not have the property: could stop existing while the clay keeps existing. 5 There is some property that the statue has that the clay does not have. 6 Leibniz s Law 7 So: the clay is not identical to the statue!!!! What could be the problem besides Leibniz s Law? Claims about what is possible?
Statue and Clay: take 2 Imagine a statue made of clay.... 1 At some time named t, the statue doesn t exist but the clay does. 2 So: the statue does not have the property: exists at time t. 3 At that time t, the clay does exist. 4 So: the clay does have the property: exists at time t. 5 There is some property that the statue has that the clay does not have. 6 Leibniz s Law 7 So: the clay is not identical to the statue. What could be the problem besides Leibniz s Law?
Table of contents 1 The Argument, first pass 2 Conceivabilitiy and Possibility 3 Leibniz s Law