Metaphysics

Argument from Semantic Determinacy of Thought

1. There is a fact of the matter about what concepts mean
2. There is no fact of the matter about what anything physical means
3. So, concepts are not physical

• O1: our thoughts aren't determinate
  • R1: self-defeating
• O2 (Peter Dillard): in computer science, there is a determinate difference between an and-gate, an or-gate
  • R1: physically determinate, not semantically determinate
• O3: neuroscience shows connection between thought and brain
  • R1: the physical is necessary, but not sufficient, for thought

• Plurality Thesis
  1. Any physical object, O, will have some particle, P, along its edge which has just as good of a claim to be part of O as to not be part of O
  2. So, O-with-P has just as much of a claim to be the object as O-without-P
  3. So, both are objects that overlap everywhere but at P
  4. There are billions of particles like P around O
  5. So, for every object O, there are billions of overlapping O’s
• Argument from the Plurality Thesis

1. PA: Physicalism is true
2. So, Plurality Thesis
3. I am in a certain psychological state, E
4. By (1), my brain, B, is in E
5. By (2) and (4), there are billions of brains in E
6. ~(5)
   • S1: I clearly don’t share my psychological states with any other brains, much less billions
7. So, ~(1)
8. So, dualism is true

• N1: this isn't quite true--disproving physicalism leaves it open that you could be an ontological idealist
• N2: proves substance dualism