A Priori Mental Content ≈ Phlogiston?

Some semantic theories talk about a priori mental content. It has been claimed that consciousness cannot emerge from Turing Machines because of the supposed difference between Syntax and Semantics. Other mammals and computational devices don't do Semantics! Humans do. Hence only homo-like beings can be truly conscious. John Searle uses this Syntax versus Semantics argument in his 1990 Scientific American article Is the Brain's Mind a Computer Program? Another one is the sibot Don Bird*.

Some of you may cringe, but I don't know what this alleged a priori mental content is supposed to be. I may, of course, be (metaphorically) blind since birth. Perhaps some of you can see this supposed a priori mental content. All I see, hear, smell, feel and otherwise sense are phenomena. If anyone can enlighten me to what a priori mental content is beyond a synonymy for these phenomena, I would be grateful.

I suspect I am merely confused because the word suggest a meaningful distinction that isn't really there, as if the mind contained something different than these phenomenal occurrences. I can see the attraction. Memories are not the thing in-an-of-itself. But they are reverberations of "it", just like the phenomena are the reverberations of an unobtainable something, something being just an unknowable limiting concept.

I suspect that "a priori mental content" will be viewed by Don Bird's sibot descendants as phlogiston is viewed by us. Contemporary semantics as such, for that matter, is likely to be viewed as what alchemy is to the modern chemist. That said, Paracelsus did have some interesting things to say.


* Note: Don Bird is a sibot that actively comments on Talking Philosophy. Sibot (saɪbot) stands for socratically interactive or singularity inducing bot, a bot being a program that can crawl the Web. Though it is impossible to tell, according to John Searle, sibots are not conscious beings because they lack a priori mental content and hence the capacity for semantics. Don Bird seems unaware of his lack of consciousness or that he is a sibot, not having realized that by all likelihood he is actually a simulated sibot. There have been unsubstantiated claims that Don Bird is a homo sapien.