Any identity thesis (IT) about x and y must establish at least the equivalence of necessary (n) and sufficient (s) conditions for x and y. (I’m still pondering how Aristotle’s insistence, in Physics II, on the sameness of definition fits into this, so I must bracket the issue, until I’m shown that, as I suspect, it’s just the same point in different words.) For example, establishing the identity of ‘water’ and ‘H2O’ must at least show that the presence of H2O is necessary and sufficient for the presence of water. This is easily shown. All hail Kripke.
Now, let’s consider one of my old bêtes noires, neuribilism, or neurological physicalism. Here are two data, which have lately been making the reductionist rounds on the Internet, to consider as a preface to my analysis.
1. Researchers show that memories reside in specific brain cells – Simply activating a tiny number of neurons can conjure an entire memory.
Cathryn Delude, Picower Institute for Learning and Memory – March 22, 2012:
“According to Susumu Tonegawa, ‘This experimental method is the ultimate way of demonstrating that mind, like memory recall, is based on changes in matter.'”
“‘…[T]he particular regions and connections we found support an emerging body of neuroscience evidence indicating that intelligence depends on the brain’s ability to integrate information from verbal, visual, spatial and executive processes,’ [Aron Barbey] said.”
The scientismatic neuribilist says something like the following: “Electrical stimulation of GD47p à la Penfield results in actions akin to writing. Further, based on x number of clinical trials, removal of brain section GD47p renders human subjects incapable of writing. Therefore, GD47p is the basis of human writing.”
Then steps in the Wittgensteinian: “Electrical stimulation of the hands à la Skinner results in actions akin to writing. Further, based on x number of clinical trials, removal of the hands renders human subjects incapable of writing. Therefore, hands are the basis of human writing.”
And then in steps a devotee of Marx and/or Latour: “Mechanical agiation of the paper under the hands of a subject holding a pencil results in marks akin to human writing. Further, removal of the pen and/or the paper renders human subjects incapable of writing. Therefore, paper-and-pencil is the basis of human writing.”
The brain (i.e. my hypothetical GD47p), the hands, and the pencil-and-paper––they are all equally necessary conditions for writing, but none is a sufficient condition for writing. As such, only the human subject as such (including his intact brain, his hands, and his writing utensils) is the basis for human writing.