ABSTRACT
At the start of chapter 1 I listed the most striking differences between past and future, namely that while we can see (or perceive by other senses) what is past, but cannot affect it, with the future it is the other way round: we can affect but not see it. This does not of course mean that we can see everything that is past or affect everything that is future. What I can see of the past depends on where I am, what I know, what I am looking for and the acuity of my eyes (with or without aids ranging from telescopes to microscopes). What I can affect of the future similarly depends on where I am, what I know, what I can think of doing, and my ability to do it (with or without aids ranging from telephones to rifles). But these constraints are contingent and variable, whereas our inability to see anything in the future or affect anything in the past seems absolute and unchanging. This is so striking a feature of time that any adequate B-theory must be able to explain it, and that is not easy.
