Albert Camus said this quote

“ Of whom and of what can I say: I know that! This heart within me I can feel, and I judge that it exists. This world I can touch, and I likewise judge that it exists. There ends all my knowledge, and the rest is construction. For if I try to seize this self of which I feel sure, if I try to define and to summarize it, it is nothing but water slipping through my fingers. I can sketch one by one all the aspects it is able to assume, all those likewise that have been attributed to it, this upbringing, this origin, this ardor or these silences, this nobility or this vileness. But aspects cannot be added up. This very heart which is mine will forever remain indefinable to me. Between the certainty I have of my existence and the content I try to give to that assurance the gap will never be filled. ”