Time, Change and Freedom

An Introduction to Metaphysics

L. Nathan Oaklander, Quentin Smith

• Publisher: Routledge
• Year: 2005
• eBook ISBN: 9781134851720
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

Written in an engaging dialogue style, Smith and Oaklander cover metaphysical topics from a student's perspective and introduce key concepts through a process of explanation, reformulation and critique.

Part I

The finite and the infinite

Quentin Smith

Dialogue 1
The beginning of time

ALICE:	A philosophy major
PHIL:	A philosophy major
SOPHIA:	A philosophy professor
IVAN:	A philosophy professor

Outside of the Lonesome Hut cabin, near the top of Mount Washington in the White Mountains in New Hampshire. Alice, Phil, Sophia and Ivan sit on a promontory, watching the stars emerge as dusk deepens. After a long silence, Alice begins to speak.

ALICE:	Do you think that the universe was always here, that time stretches back earlier and earlier into the past, without any beginning at all? Or did everything have a beginning? Did time begin?
PHIL:	Time begin? How could time begin? Everything that begins, begins in time, so time itself cannot begin.
ALICE:	Explain that. Why cannot time begin?
PHIL:	If something begins, that means there was an earlier time at which the thing did not exist and a later time at which the thing exists. So if time itself began, that would imply there was an earlier time at which time did not exist and a later time at which time exists. In short, it implies there is a time earlier than the earliest time. It is clear that is a contradiction. So past time must be without a beginning. It is infinite.
SOPHIA:	Let me interject here. I understand what you are saying, Phil, but there is a different way of viewing the matter. Time does not begin in the same way that things in time begin. Time begins if there is a first moment, a moment before which there are no other moments. There are two senses of “Something begins.” In one sense it means “There was a time at which something did not exist and a later time at which it does exist” and in another sense it means “Something is the earliest moment of time, so that all other moments are later than it.” Time “begins” in the second sense.
PHIL:	That is hard to conceive. Is there any reason to think that time did begin?
SOPHIA:	Some scientists today believe that time did begin. They believe that time began about 15 billion years ago with the so-called “big bang,” an explosion of matter, energy and space out of nothingness. At the first time, there existed only an extremely tiny but very dense speck of matter. This speck of matter was so tiny it was much smaller even than an atom. This speck of matter instantaneously exploded in the powerful explosion called the big bang. As this matter exploded, the space containing it began to expand, much like the surface of an expanding balloon. This expansion is still going on today; the universe is growing larger in volume at every moment.
IVAN:	Sophia is right. The physicist Stephen Hawking says that time began with the beginning of the big bang explosion. He says that to ask what occurred before this explosion is like asking what is north of the North Pole. There is nothing that is north of the North Pole, and there is nothing that occurred before the big bang.
PHIL:	I have some difficulty in understanding this idea, and am not quite sure I really can believe it, despite the fact that Stephen Hawking and some other scientists believe it is true. Suppose I am somehow located at the moment of the big bang. I can then conceive of a moment before this moment and if I can do this, that seems to suggest there is an earlier moment.
ALICE:	I can see the fallacy in that argument. Surely you could conceive of an earlier time, but that does not mean there was an earlier time. In fact, your concept will not refer to anything, since there was no earlier moment for it to refer to. You are at the big bang, trying to think of an earlier time, but in fact there is in reality nothing corresponding to your thoughts.
PHIL:	But I think your own remarks imply there must have been an earlier time. Consider the statement, there was nothing before the big bang. That implies that there was a time before the big bang, a time at which there was nothing.
IVAN:	Let me give a precise and logical formulation of your argument, Phil, and see what Sophia has to say about it. I don’t agree with the argument myself, but I am interested to see how Sophia responds to it. The argument goes like this. Either there was something occurring before the big bang or there was nothing occurring before the big bang. In either case, there is an earlier time at which there either was something or nothing occurring. The contradiction also appears when we say “There was no time before the big bang” for “there was” and “before” refer to the past time that preceded the big bang.
SOPHIA:	I think you are again confusing talk about time with talk about things in time. “There was no time before the big bang” does not mean “At the time before the big bang, there was no time.” Suppose we are all located at the big bang. We could then take “There was no time before the big bang” to convey that “It is now true that time Is and Will Be but it is now false that time Was.”
IVAN:	Sophia, let me elaborate on your point, which seems on the right track. If we are located at the big bang, then we should say that the notion of “there was…” has no application at all. “There now is…” refers to something and “there will be…” refers to something, but “there was…” does not. Likewise, we should say that the notion of “before the big bang” has no application at all; only the expressions “simultaneously with the big bang” and “later than the big bang” have application.
PHIL:	That is clearer. I think I am beginning to see. Maybe your point can be put metaphorically. If we are at the big bang and try to turn our thoughts towards the past, we encounter an invisible wall of nothingness. There is nothing at all there.
IVAN:	Sophia, let me go back to something you said earlier. You stated that “Time begins” means “There is a first moment of time.” I do not think that is a very good definition of “Time begins,” since there is a sense in which time begins even though time lacks an earliest moment. Time began 15 billion years ago, but for every moment of time, there is an earlier moment.
SOPHIA:	Explain exactly what you are getting at, Ivan.
IVAN:	Take the first hour of time. Is that the first time? No, since there is a shorter interval of time that elapses before the first hour elapses. There are sixty minutes in an hour and the first of these minutes must elapse before the whole hour can elapse. Moreover, before the first minute elapses, the first second elapses, and before the first second, the first one-tenth of a second, and so on infinitely. Since there is no shortest temporal interval, there is no interval of time that can be identified as the first interval of time. For any interval of time that elapses during the first hour, there is a shorter interval that elapses first. Thus, there is no “first moment of time” in the sense of an interval of time that precedes every other interval.
SOPHIA:	But if time begins, there is an earliest interval of time of each length. For example, there is a first second, a first hour, a first year and so on. That is what I meant by saying that “Time begins” means “There is a first moment of time.”
IVAN:	But Sophia, even that is not quite right. It is right only if future time is endless. But it is wrong if time comes to an end. Suppose time begins, and ends 30 billion years later. If so, there is a first second and a first hour and a first year, but there is no first interval of the length 40 billion years, since no intervals of this length exist. So in this case your statement that “There is an earliest interval of time each length” would be false.
SOPHIA:	I see your point, Ivan. What I should say, to be strictly accurate, is that “Time begins” means there is a first interval of time of some length (but not necessarily of every length). Time begins, for example, if there is a first second, even if there is no first interval of the length 40 billion years.
IVAN:	All right, I agree that is a good definition of “Time begins.”
ALICE:	I am not entirely sure about everything that you are both agreeing upon, Ivan and Sophia. Ivan, you said that there is no earliest interval of time, since for every actual interval, there is a shorter interval that elapses first. This implies that there are an infinite number of shorter and shorter intervals. But why should we think that time is infinitely divisible? Why can’t there be a shortest interval, say an interval that lasts for one-millionth of a second? If there were, then the first interval of that length would indeed be the first interval of time. There would be no interval of any length that elapsed before that interval elapsed.
IVAN:	The view that time has a shortest interval that is not further divisible is the view that time is discrete. This means that there is some shortest interval of time, say one-millionth of a second, and that there is no period of time shorter than this. Some physicists think that quantum mechanics implies that there is a shortest interval, an interval that lasts for only 10^–43 second. This is 1/100000…of a second, where there are forty-three zeros after the 1. This is an extremely short period of time, far shorter than one-trillionth of a second. But I think that physicists are best understood as saying that it is impossible to observe any interval of time that is shorter than 10^–43 second. I think it is a conceptual necessity that for any interval of time, there must be a shorter interval.

ALICE:	I do not see why this is a “conceptual necessity,” as you call it.
IVAN:	It is a conceptual necessity since a temporal interval by its very nature contains successive parts. In order for any interval to elapse, the first half of the interval must elapse before the second half elapses. Thus, any interva...

Table of contents

• COVER PAGE
• TITLE PAGE
• COPYRIGHT PAGE
• INTRODUCTION
• PART I: THE FINITE AND THE INFINITE
• PART II: TIME AND IDENTITY
• PART III: THE NATURE OF FREEDOM
• APPENDIX: PHYSICAL TIME AND THE UNIVERSE