The Internet Encyclopedia of Philosophy “Time,” by Bradley Dowden, The Internet Encyclopedia of Philosophy, ISSN 2161-0002, https://iep.utm.edu/time/, 2024/03/28.

Time by Bradley Dowden

Time is what clocks are used to measure. Information about time tells the durations of events, and when they occur, and which events happen before which others, so time plays a very significant role in the universe’s structure, including the structure of our personal lives. But carefully describing time’s properties has led to many unresolved issues, both philosophical and scientific.

Consider this issue upon which philosophers are deeply divided: What sort of ontological differences are there among the present, the past and the future? There are three competing philosophical theories.

Presentism implies that necessarily only present objects and present events are real, and we conscious beings can recognize this in the special vividness of our present experiences compared to our relatively dim memories of past experiences and dim expectations of future experiences. So, the dinosaurs have slipped out of reality even though our current ideas of them have not.

However, the growing-past theory implies the past and present are both real, but the future is not, because the future is indeterminate or merely potential. Dinosaurs are real, but our future death is not.

The third theory, eternalism, is that there are no objective ontological differences among present, past, and future because the differences are merely subjective, such as depending upon whose present we are talking about.