after 3000 times of defining "metaphysics" as the "basis of science"
That's not a definition. A definition ought to be a series of words that allows one to understand what a person means when he uses it and identify an item that meets the definition and one that doesn't. Thus a definition of woman (biological sense) ought to be something like an adult, female human.
If any of those words are unfamiliar or ambiguous, then they can be defined as well, and that definition substituted: Adult - the mature form of an organism; Female - the gender that produces ova; Human - a linguistic primate. Thus, a woman is the mature, ova producing primate that speaks.
Assuming that one doesn't need any of those words defined for him, he can now identify whether a particular thing is a woman or not. How about this book? Nope. It meets none of the criteria. How about this tree? Nope, not a primate. How about this infant girl or her father? Nope, but getting closer. How about her mother? Bingo.
Now look again at what you are calling a definition.
You want to ignore things like we each see what we believe and nothing else.
Because it's incorrect. You like to make claims like this, but all it takes is one falsifying experience to reject any claim - one instance of seeing something one believed was untrue and having his mind changed by evidence.
All evidence is interpreted in terms of one's existing models and beliefs and no two people share the same models and beliefs.
Yet somehow, most critical thinkers come to the same conclusions about any piece of evidence. You seem to believe that we all have a personal way of processing information.
Do you also believe that all opinions are equal and equally valid? That's Dunning-Kruger territory - the people unfamiliar with critical thought and empiricism, and its power to elicit useful and correct ideas (knowledge, truth). Since they are only aware of one way of coming to belief - the one I call faith, or holding unjustified belief, in this case, because one doesn't know about justified belief, they consider all opinions equally valid.
We all seek a solid ground, a lifeline, or floating debris in the a vast sea of ignorance. There is none. We must embrace our ignorance and allow ourselves to be embraced by it.
Yes, there are limits to our knowledge, yet we can still use that knowledge to make our lives and the world a better place. You spend a lot of time discussing what we don't know and seem to miss that there is much we do know that can be quite useful to know.