Physical Time and Intrinsic Temporality

Abstract

Physical theories distinguish two notions of time: reversible, homogeneousparameter time (relativity theory and quantum mechanics) and irreversible,directed time (thermodynamics). Both concepts differ fundamentally from whatwe define implicitly by using the tenses and temporal adverbs in language. Thetempora past, present, and future hinge upon one uniquely exposed moment: thenow. The now is the moment of actuality in the process of subjective awareness.It proceeds spontaneously and irresistibly in relation to all datable points of time.Without reference to the moving now, past and future only denote directions intime. But there is no physical definition of the now. Physical time, be it reversibleor irreversible, differs from subjectively experienced time in that it is atemporal.Because physics has no notion of the now it cannot genuinely treat past andfuture as temporal regions. As a physicist, Einstein consistently declared thedivision of time into these regions as illusory. In the first two sections of thispaper we reaffirm that Einstein was right on logical grounds. In the third section,however, we insist that the actuality of the now and its movement are truths thatlogical reason has not the power to question. In the fourth section we shall belooking for a clue to escape the dilemma.