The next installment of the never-ending argument:
“additionally, if it is true that empirical properties have inherent meaning, then it is not true that metaphysical theories cannot be tested by empirical measurement. The argument runs in circles: You assert that metaphysical theories are not empirical, and then you use this to further assert that the opposite theory is self-refuting, because it cannot be tested empirically, which is due to the first assertion. So your whole argument amounts to just a plain denial of the other guy’s axiom.”
Not so. You are mistaking my conclusion for my axiom here. I take it as an axiom that the word “empirical” means “depending upon experience or observation alone.” Observation involves the five senses and what can be deduced from them. I take it as granted that no observation can support anything other than contingent and conditional truths.
Example: we can say the sun rose yesterday, but to say the sun will rise tomorrow, whatever else it may be, is not an empirically proven truth. It is not an absolute statement, true under all times, conditions, places circumstances. It requires no great imagination to picture a tide locked world of the remote future when rotation has stopped, and the sun will not rise. Such a counter-factual is possible.
Metaphysical statements are those which concern the subject matter of first principles necessary to other disciplines, such as the first principles of physics or epistemology. This is the definition: whether there are any members of the set or no remains to be seen.
The statement “all knowledge whatsoever is empirical; there is no non-empirical knowledge” is a universal statement, an absolute statement.
An absolute statement is (or alleges to be) true under all places, conditions and circumstances.
Certain things follow from this: In this case, if knowledge is empirical and no non-empirical sources of knowledge exist, it is meaningless to say that non-empirical knowledge existed in prehistory, or beyond the moon, or some sphere orbiting Achernar.
If the statement is true, it must be true everywhere and for all rational beings, because it is a statement about the nature of knowledge, not a statement about the biological sense apparatus of humans versus Martians, or the brain structure of men versus elves. Even if Martians were mind-readers the knowledge entering their brains could not be non-empirical knowledge: their mind-reading antennae (or whatever) would merely be another organ of sensation like earthly eyeballs.
If the statement is true, no counter-factual is possible. If no counter-factual is possible, the attempt to describe the nature of knowledge in any non-empirical terms is and must be nonsense, something that exists in words only, but which, upon examination is an incoherent or illogical description. If no counter-factual is possible, then trying to imagine a universe where other forms or other sources of knowledge existed would be as impossible as imagining a universe where twice two was not four, or “A is A” were false.
So, by definition, metaphysical statements are universal and absolute. True everywhere and always, no matter what our senses say. Empirical statements are contingent and conditional. True here and now, and only because our sense do not yet show us any exceptions or variation.
So, then: if the statement “all knowledge whatsoever is empirical” were an empirical conclusion from sense data, a skeptic could be shown the sense data. The skeptic could look through a telescope at “knowledge” or loft it in his hand, and see its visible and or feel its tangible properties. And if one of the properties were “Always empirical” the skeptic could see and feel that as well.
But if the statement “all knowledge whatsoever is empirical” were a metaphysical deduction from first principles, such as, for example, a deduction from the axiom that truth is a correspondence between sense impressions and sense data, then only a metaphysical argument could convince a skeptic of its truth.
At this point, I merely call upon you to observe which sort of argument convinced you, or anyone, of the statement. Since an empirical argument in favor of a metaphysical ergo universal proposition is impossible by definition, the argument must be metaphysical.
There is no circularity in my argument. It consists of two definitions and an invitation that you see which definition fits the subject matter.
The only room for argument is that I have wrongly defined the statement as falling under an empirical definition. In that case, all that need be shown is the empirical proof of the statement, and not an argument from first principles.
I challenge you or anyone to show me empirical proof that no non-empirical source of knowledge exists for Martians of the year Two Billion AD. Produce the telescope that sees the abstract nature of knowledge rather than objects lit with light, and I will bend my eye to the lens and look through it.
Another option is to amend the statement and make it properly empirical, such as by saying you yourself have never seen any non-empirical knowledge so far in your life; that you do not know good from evil or fair from foul or logical from illogical. This statement would be easier to defend, since it is not an absolute statement, but it involves the argument in additional difficulties.