Here is the original explanation of how Lessans committed to modal fallacy. Can you address it?
Quote:
Originally Posted by davidm
Your argument commits the modal fallacy.
Let us assume, for argument’s sake, that all of us invariably do what we think will bring us the greatest satisfaction (a premise that I find highly dubious, but let’s just assume it for argument’s sake.)
Your argument, or the author’s argument, seems to go: If option A is best for me, than I must choose option A (hence, no free will).
This commits the fallacy of modal logic, illicitly assigning neccessity to a contingent outcome.
If indeed there is a “necessity” component to your argument (true in all possible worlds,) then the necessity lies, not in the consequent, but in the conjoint relation between the consequent and the antecedent.
Assuming the truth of the claim that we all invariably choose what we think is best for us, the proper logical construction is:
Necessarily, (If I think A is best for me, then I will (Not Must!) choose A)
And NOT:
If I think A is best for me, then I must (necessarily) choose A.
The modal fallacy here is plain to see, and the author’s argument against free will is formally logically invalid, and needs no further rebuttal.
For more on the modal fallacy, see here, for example. |