 There are different examples that draw upon our experience of pain and our attitude towards it. Consider again a past headache and compare it to a (possible) future headache, something that may result from overenthusiastic behavior in the bar this evening. A future headache is something that worries us. It influences our behavior. We seek to avoid it. We may even fear it. By contrast, we feel differently about past headaches (and past pains, generally). We don’t fear past pains. They don’t worry us in quite the same way. One explanation for this is that a past pain doesn’t exist. Whilst a future pain doesn’t exist either, we know that it will exist if we behave in such-and-such a way. It’s the potential for that headache to exist (to come into being) that causes us to modify our behavior. We wish to avoid that state. But if we think that past and future things exist, we cannot appeal to the explanation just given, for if the past headache exists, presumably we should fear it or worry about it, just as we should if a future headache exists. (For a brief, general discussion of connections between time and rationality, see the entry on  time:  §12. For further reading on ‘time biases’ — such as ‘future bias’, where an agent prefers that bad or painful experiences be in the past and that good or pleasurable experiences be in the future — see, e.g., Hare 2007, 2013; Sullivan 2017, 2018; Bnefsi 2020; Fernandes 2021.)