The point of philosophy is to entertain all those thoughts and THEN try to find something true without going back to the scientific viewpoint. The latter is the "they" of Heidegger

I doubt my existence more often than I believe in it. I must be in a different state of mind — Gregory

Well to be precise I should say that it makes no sense to doubt your own existence. Obviously one can try and doubt their existence or they might erroneously question theyre existence not knowing cogito ergo sum, so you are correct in some sense but not in the context of certainty. You can be certain that you exist, that you have some kind of existence.

Also, cannot be in a different state of mind if you do not exist.

I am willing to bend the rules of logic in a search of my existence, which search might simply end in reading "the sentence" of the Absolute Idea.

Imagine Galileo taking his material objects into his hands and dropping them ten times. They fell at the same rate, history says. He felt satisfied that the law wasn't that on the eleventh the objects would descend at uneven rates. His psychology defined his physics, which was simply philosophy. I believe in the possibility of psychic phenomena. Einstein i see as a good witch doctor or a not Satanic Crowley. Science can never disprove magic, will say it comes from other dimensions, and is probably based on magic in its success.

My brother today said "I want to know what they put in this diet dr. Pepper" . I responded "where do you get the information that would even make the answer to your question even meaningful" . I think the answers to my question is psychology.

So yes, physics is a branch of psgchology, which is a branch of philosophy