Truth, which is the alignment of our intelligence with what is outside of us and points to the fact that reality (that which is external to the person, exists independently of him, and is the same for everyone) is the foundation of knowledge, presents itself to man as certain or absolute, and in trying to deny it, man contradicts himself because he eventually ends up saying exactly what he wants to deny. For example, when someone says “there is no truth,” he presupposes precisely the opposite, that what he said (“there is no truth”) is true, i.e., corresponds to the fact that there is a “common ground” (reality) between him and the other, independent of the two, and for that reason the other understands him, underlying that what he says is objective and not based on the subject.
When a person says something, he presupposes that what is actually said is that way because reality is this “common” or “third” element which is independent, autonomous, and shared between the speaker and the listener. In saying something to someone, it is assumed that the other person understands what is being said, precisely because the thing affirmed does not depend on the person that says it. For example, if someone says, “this tree is green” he presupposes that the other person already understands what is “a tree” and what is “green”. This is because both elements are independent of individual perception. If you pretend that everything is subjective and that knowledge depends on the perception or opinion of each person, there would be no hope that other people would understand you. “Green” for one could be “purple” to another, and they would never come to understand each other.
There would be no certainty about anything if it all depends on how you look at it and not how things are in themselves because there would be no way to know if what is outside of you is really that way. There would then be a separation between the subject and everything that surrounds him. He would be like an island with no possibility of “touching” or “connecting” with others because personal or private perception would manipulate everything. Without reference to something real, something objective or common, all human interaction would be insecure, empty, and meaningless, given that there would be no way of knowing if what someone says is real.
Thus, when one says that “truth does not exist”, it is as absurd as saying “red is not a color”. But even as he says this, it is assumed that the other person knows what “color” is and what “red” is, otherwise, the words would have no meaning for the other person. It would be like saying “ggxxdd is not a color” because if red were not a color it would remain empty of any essence and no one would understand. Conversely, if I did say something like that, I would presuppose that the other person understands, by the ideabehind the word “red”, that it is a color, and so I end up presuming what I was trying to deny: that red is a color.
To say that there is no truth is as absurd as saying “I do not exist” because to say “I” presuppose a subject that exists, otherwise it would not even be possible to be aware of an “I” if it did not exist previously; similar to saying that “words do not exist” when they are precisely what I’m using to express this. So, to think you cannot know reality as it is in itself, but only perceptions, but at the same time pretend that there is something objective or common to be able to understand the other, will always be contradictory, which indicates in itself that there is no way to reduce everything to the subjective.
To say that I cannot know things as they really are and that everything is just subjective perception presupposes, at least at some point, that there iscertain knowledge of reality, which is precisely to recognize that it exists and has a particular way of existing — that of being “unknown and manipulated by the subject “ — i.e., something objective. Therefore, prior to this knowledge that reality is supposedly subjective, it is necessary to have contact with that which is outside of me, with the reality around me, through an experience which provides such specific knowledge; otherwise, I would not know if it were even possible to know or not, or if what I knew was mere perception or not.
Ultimately, to assert that “we are ignorant of the way things are in themselves”, I should have previously presupposed that there are really “things in themselves”, and that they are “independent of me”, regardless of my perception, which indicates that I did indeed obtain concrete and objective knowledge of reality which ultimately denies my ignorance of it.