You are right, technically speaking, but the preponderance of indirect evidence that does exist suggests that there is high likelihood that he did exist. Much more than, say, Achilles.
Whether he actually said what he is rumored to have said is a different story. But the important distinction is that doubt in Washington's sayings is not something you have to fear will send you to hell. No one expects dogmatic and absolute belief of historical accounts the way Bible-worshipers insist that what's in the Bible is true and inerrant.
You would have to be omniscient to know that nothing supernatural has been discovered, which is self-refuting
No, because if it were discovered it would be known. The only thing that is self-refuting is a claim that a book, which is full or errors is without any.
Whether he actually said what he is rumored to have said is a different story. But the important distinction is that doubt in Washington's sayings is not something you have to fear will send you to hell...
Then we agree at least that all existence or factual questions are not established or disconfirmed in the same way in every case and that the type of evidence in existence or factual claims is determined by the field of discussion and by the metaphysical nature of the entity in the claim under question.
If George Washington had claimed in the presence of eyewitnesses who were capable of accurately transcribing what he said, that he was the Messiah, the Son of God, that he had had glory with the Father before the world began, that he was the light of the world, that he had the ability to give people eternal life, that no one comes to God except through him, and that (like Obama may think) he possessed all authority in heaven and on earth and therefore men should obey all His commands, or that he would judge the living and the dead, predicted that he would lay down his life for the Federalists, that he would raise himself bodily from the dead the third day, and that Philadelphia would be completely destroyed within a generation, then yes, such extraordinary claims would require sufficient evidence of their veracity, and without any confirming evidence and/or in the presence of contradictory evidence we would just chalk him up as a lunatic.
No, because if it were discovered it would be known.
No, just because you have not discovered it does not mean that it is not known. I'm still assuming that you do not have the attribute of omniscience that enables you to know all things.
There is no shortage of empirical evidences of the historical claims of the Bible. When you say that if such evidence were discovered it would be known, all you are doing is precluding the very possibility of any of the available historical evidence counting as proof - not because you have proved by empirical observation and logic your own pre-commitment to naturalism, but by the very nature of a presuppostion, you accept and reject all further factual claims in terms of that controlling and unproved assumption.
Cordially,