You mean there is no objective method. Subjectively, I know that mental phenomena exist, because I experience it. That's how I can know with certainty that nobody else can be a solipsist, to the extent one takes solipsism seriously. — Marchesk
No, I mean there is no logical method if it is undecidable.
You mean to be sure other people have mental content? Because again, I experience my thoughts, my perspective, my dreams, etc. Whatever mental content are, I have them, and I cannot doubt that I have these experiences, however one wishes to categorize them. — Marchesk
To say you are definitively aware of experiencing your thoughts, to physicalist, is no different from saying there is an effective method for being certain about the existence of your thoughts.
That is to say that thoughts are decidable.
If they are not decidable that poses problems for physicalism sure, it would mean that we cannot
logically determine if we experience intentional states.
But it would also be a problem for everyone else as well.
You mean what can be objectively known. Here is a potential problem for physicalism. It beings with objectivity, which means factoring out our individual subjective experiences. This works great for science. But it has the one big problem of turning around and explaining subjectivity, because at the start, subjectivity was removed. — Marchesk
There would be no logical method to decide, subjectively or objectively, that we have experiences.
If there is a logical method for deciding the existence of experiences and intentional states then there is no issue for physicalism.
In Lockean terms, you get rind of color, sounds, smells, etc to explain the world in terms of number, shape, extension, etc. That's great until you need to account for our having colors, smells, etc. — Marchesk
If a color or smell is undecidable then how could you be certain you were experiencing colors or smells?
If you can be certain physicalism assumes this means these things are decidable and that therefor an effective mechanical procedure is the account.
Sure it would be more interesting if we imagine that there is something else going on, but no breakthroughs in methodology exist to warrant such speculation, it is simply a speculation for speculations sake.
There is no issue for a physicalist because if you can be certain about these things, then that means these things are decidable, which means that there is an effective mechanical procedure to account for that decidability.
That leaves two options, these things are not decidable, a problem for the physicalist and everyone else.
Or there is some other method for decidable problems in new formal systems of logic as of yet undiscovered, an unnecessary assumption at this point.
How does one derive smell from number? Is there a mathematical equation for experience? Do you now what sort of algorithm would enable a machine to experience the sweet smell of rose? — Marchesk
The answer is simple.
How does one know for certain if there is a smell such that this question is answered definitively yes or no?
The only currently known method for this is with an effective procedure of finite steps.
Or
decidability.
If there is no effective method and a smell is an undecidable thing, then this is not simply an issue for physicalism, it is an issue for anybody claiming that they smell.
If smell was undecidable you would not actually know if you smell or not.
For a physicalist saying that you know for certain that you smell is the logical equivalent of saying there is an effective method for deciding that you smell.
You can conjecture that decisions about the existence of intentional states and/or experiences is undecidable from current understandings in logic, sure.
It is probably more interesting than the physicalist position, sure.
But it certainly isn't logically necessary to speculate thus, at least not at this point.