Bertrand Russell holds that, in dissussing self-evidence, one should speak of self-evident beliefs rather than of self-evident propositions, for self-evidence, in his view, can be defined only in reference to a certain subject or certain psychological states of mind. Knowledge is said to be self-evident when it is achieved through senses and this sort of Knowledge is not self-evident unless it is perceived.
Thus, it is not the nature of a proposition is one and the same before and after it is perceived. Therefore, the real self-evidence is and attribute or a property which is related to a certain subject at a certain time.