1 Some Questions about Time to Guide Our Discussion (and Make the Time We Spend Talking about Time Fruitful) Some questions about time from Bob Muir: 1. What is it in our experience that we call time? 2. How would you describe an experience without time? 3. Why do we refer to the flow of time? 4. Does time flow or do we flow through it? 5. Isn't time just a word we use to describe the experience of change? 6. In other words, is the nature of time really elusive or just hard to express? 7. By definition we never experience either the past or the present, so why do we refer to them as if they exist? Some questions about time from Bob Shepherd: Question 1. Presentism is the view that a) the past is gone and no longer exists and b) the future hasn t yet happened and doesn t exist, so c) all that s left is the present, which is ALL that exists (and is continually changing). This view is commonly referred to in the philosophical literature as the A-Theory of Time or as Property Time. It s the commonsense view that time consists of events, most of which don t exist, that have the properties of being past, present, or future. (A thing that doesn t really exist can nonetheless have properties. Pegasus and Supergirl, for example, can both fly. Philosophers have long argued about whether numbers and mathematics really exist, but whether they do or not, the numbers 2 and 68 are both even and mathematics is tautological.) A common objection to Presentism is that the past and the future can be measured ever more finely so that the present ends up being infinitely small and not
2 existing. Another is that the present can t be grasped, that it is always gone when we try to grasp it and has been replaced with what was the future, so it s truer to say that we are always living in/experiencing the future. According to this eternal frustration argument, we are in a perpetual state of lurching forward. Is Presentism true? false? nonsensical? Do the arguments for or against Presentism make sense? Question 2. One alternative to Presentism is Block Time. One common view of Block Time is that while past, present, and future are unintelligible notions, we can start speaking sense if we say, instead, that a) events exist and b) they are all earlier than, simultaneous with, or later than one another. To restate that: events exist but have these relations to one another of being earlier, simultaneous, or later. (One way to think of this view: Events are like points in space. Point A doesn t cease to exist when you move to Point B. It s still there, but it s in a different place in space. For a proponent of Block Time, a past event your birth, say is still there, but it s in a different place in time.) For reasons that I shall discuss briefly when we meet, Einstein (who was a reasonably smart fellow by most accounts) believed it a consequence of his Theory of Relativity that Block Time is a correct description of the universe, that all events exist and that time and its arrow are both persistent illusions, though individual observers always perceive themselves as existing within a time that has an arrow. 1 This view, for which there is considerable scientific and mathematical evidence, is variously referred 1 For Einstein s seventieth birthday, his friend the mathematician Kurt Gödel presented him with a paper containing solutions for Einstein equations that presented two possibilities: Block Time and Eternally Recurring or Cyclical Time. See Question 3, below.
3 to in the philosophical literature as the B-Theory of Time, Relational Time, The Tenseless Theory of Time, or Indexical Time. Is Block Time true? (BTW: It is not a consequence of the Block Time theory that Determinism is true; the two ideas are separable, but that s another discussion.) Question 3. In The Gay Science, Nietzsche, whom we met last time, raises the following question: If all moments of time recurred eternally, so that you would relive them again and again, forever, would you see this as a joyful thing or as the greatest weight? If this were true, how would you change the way you are living your life right now, what you plan to do with it tomorrow? Would you accept what you are doing if you had to do it again and again forever? This question of the Eternal Return can be posed in terms of Block Time, of course, rather than in terms of time that returns again and again. So, what is your answer to Nietzsche s question? What will you do with your one wild and wonderful life? asked the poet Mary Oliver. Good question. Question 4. One view of time, deriving from cognitive psychology, is that we have completely different and incompatible systems in our heads for perceiving time in different ways and that we switch among these as the situation requires. So, we switch to a Newtonian, Absolute Time system when we have to do something that involves synchronizing our actions (as when musicians play a piece with one another). We switch to the Past, Present, and Future time system when we have to do something that involves planning or retrospective analysis (Should I have kissed her? Should I kiss her?)
4 Ordinarily, we operate on the Subjective Time system, which has a longer or shorter Perceived, Durative, Extended Present (I need to go to the bathroom. Did she look at me? OMG, will that guy Bob Shepherd EVER stop talking?) Kant famously and at considerable length argued that we can t know the universe as it is in itself but only as it is to our particular constitutive, constituting minds. If that s true (and how could it not be?), when we switch between systems, are we switching between different constitutive minds and thus switching between different universes as they are constituted by our minds and as they are known to us? Does the possibility that we are doing this require us to adopt some degree of skepticism and, as a result of that, pragmatism? Question 5. Some philosophers would like to throw out fruitless questions about time like some of those given above and to have us concentrate, instead, on what we in fact experience (Remember Bob Muir s question, Isn t time just a word we use to describe experiences? ) Husserl and Heidegger and Muir seem to be in agreement about this, but the first two, at least, also seem to disagree fundamentally in where they take this thought. Husserl believed that our experience of the present is fundamental to our Being and that we construct our notions of the past and future from present experience of phenomena a) that we are aware of having been present but that are not present now (the past) and b) that we can think about now but that are neither in the present nor remembered as having been in a present and so must be somewhere else (the
5 future). Heidegger thought that nonsense. He thought that the future is fundamental to our Being, that we cannot be other than future-oriented because that s the sort of Beings we are. We are entities that are becomings, that are and have projects and that care about those. Which view makes more sense to you and why? Some other questions that we won t have time to discuss but that will come up if we discuss the items above: If time has an arrow, is this stoppable or reversible? Is it possible to skip forward in time? (The answer to that is yes relative to a stationary observer but We don t know otherwise) or backward in time? (The answer to that is just We don t know ).