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I was recently speaking with someone who had an argument about whether time

I was recently speaking with someone who had an argument about whether time exists or not. Time Dilation is often put forward as proof that time exists and that it is not merely a figment of imagination of mankind. But this person argued that by believing this, we are making a self-contained assumption about time. He argued that time is actually just the measurement of change that occurs in an object relative to constant natural phenomena. For instance, atomic clocks measure the microwave emissions of changing electrons, and older clocks measure the degree of the earth's rotation. He suggests that it is a huge and erroneous jump to say that these things measure anything other than what is stated i.e. emissions of changing electrons or the degree of the earth's rotation, and that to say that they measure a force or external entity that is time is simply illogical. And I would be inclined to agree. I watched a Stephen Hawking program where he discussed the possibility of time travel. He spoke about the...

As you may sense yourself, part of the problem is to decide just what question we're asking and what would count as an answer.

Start with space. One way of claiming that space is real is to say that it's a thing -- a "substance", as the jargon of philosophy would have it. (In this sense, a substance is something that _has_ properties or qualities and stands in various relations, but isn't a property or a relation. An atom is a substance in this sense; so is an animal.)

The "substantival" view of space-time has its adherents, but also has its detractors. There are many philosophers who don't think space is real if that would imply that it's some kind of thing. Typically such philosophers would say that instead of talking about space as such, we should talk about spatial relations. Things can be between other things, or beside them or above the, or longer than them or a certain distance away from them. What's real, on this view, are the things that stand in the various relations; space isn't something above and beyond all those relational facts.

Obviously we could think of time in much the same way: time isn't a thing or a substance; rather, events (happening, occurrences) have relations such as earlier than, simultaneous with, ten minutes later than... among them. On this sort of view, that's all there is to the notion of time; it's not a thing, let alone a thing that influences more ordinary objects.

Once again, there are plenty of philosophers who prefer this view, and if talk of the reality of time is talk of there being some special _thing_, then lots of non-crazy people don't believe that time is real in that sense. What's real are things of more ordinary sorts (including the not-so-ordinary things of physics) and events of various kinds. Some of the facts about these things are facts about distance, relative location, before-and-after, etc. This ia an attractive thought because it takes away a lot of mystery: if time is a thing, what sort of thing could it possibly be?

Whatever we make of this view, it doesn't exhaust the issue. We can ask: are spatial and temporal relations objective? Or are they conventional? Is it an objective fact that the clock we use to measure time ticks regularly? Or do we _decide_ for various reasons to treat one kind of time-keeping device as the standard rather than another without there being any objective fact about whether it really ticks regularly? This isn't an easy issue, and there's lots of disagreement about it among philosophers.What we see, however, is that even if space and time are matters of relations, people can differ over the objectivity and hence, in an important sense, the _reality_ of the relations.

Your questions about relativity are good ones and they don't have easy answers. As it's often presented, relativity seems to fit best with something like a substance view of space-time. I say "space-time" because in relativity space and time are mathematically related in particularly intimate ways. According to general relativity, space-time doesn't obey the laws of Euclidean geometry, and in fact it departs from the Euclidean to varying degrees and in various ways depending on the background configuration of matter. In fact, on one common way of putting it, space-time tells matter how to move, matter tells space-time how to curve. On this view, space-time acts on matter and matter acts on space-time. If that's right, space-time seems pretty real. (Keep in mind: in relativity, time isn't something distinct from space. What's at issue are questions about space-time.)

The issues here are complicated, but there's no question of a mere leap in logic. General relativity is a complex and subtle account of spatio-temporal matters. On its face, it seems to posit something akin to the electromagnetic field, except it's a field that acts on all matter. Whether that's the best way to look at it is not an easy question, but what seems clear is that the view isn't the result of any simple mistake in reasoning. It's a matter of how best to make sense of a complicated web of theory and fact.

I'm confused by the saying "God transcends time" . To me it seems time is change

I'm confused by the saying "God transcends time" . To me it seems time is change ( thoughts, actions , and any other form of change ) So transcending time doesn't make any sense as you would need to change in some way to create the universe ,because To be timeless ( due to transcending time not making sense )would mean to be forever timeless if there is no form of change to cause you to change yourself. With this in mind wouldn't god creating the universe mean god exists within time? This would restrict god with the question of "where did it come from" due to it also being a timed being with a required beginning to initiate change. So what i'm trying to ask is, am i missing something? is it just that i'm not taking something into account that lead me to deduce this as impossible? I'm only 17 and i always hear this from many adults who have faith in god and i just ponder in my head how they could think this to be true. I'm not stating no god exists, nor that one does, i simply think this idea of...

Great observations and great questions! There are three views that are defended today by philosophers in the theistic tradition (the tradition that holds that there is a God who exists necessarily, is all good, omnipotent, omniscient, omnipresent, and the creator and conserver of the whole cosmos). On a traditional view (going back to Boethius and Aquinas) God is eternal in the sense that there is not before, during, or after for God. God's creating the cosmos as well as all God's acts are timelessly willed. On this model, God timelessly wills successiveness (the origin and sustaining of a changing cosmos) but God does not successively will (God wills at one time to do X and then do Y). This position is defended by many philosophical theists such as Brian Leftow at Oxford University. He is the author of the book Time and Eternity, which you might check out. Then there is the view called Open Theism which holds that God is in time God is present throughout all the created order NOW and is everlasting (that is, God has no beginning and no end). I do not think that if something is in time, it follows that it had a beginning or origin. I bet this sounds crazy to you, but some philosophers (like myself) think there are abstract objects like numbers that exist necessarily and never had an origin and will have no end. There is a third view championed by W.L. Craig which is quite interesting: he holds that God was timelessly eternal until creation, after which God is temporal. You can do a google to find Craig's home page in which he has posted various papers on this and other topics.

I want to encourage you in your questions and inquiry!!!!!!!! The intersection of the philosophy of time and philosophy of God is fascinating. You might look to the free Stanford Encyclopedia entry on philosophy of religion and entries on time.

Seeing that most languages require that sentences to have tense, can we actually

Seeing that most languages require that sentences to have tense, can we actually have any progress discussing time? I mean every sentence by its structure already assumes a understanding of time , how do we ever transcend the bounds of our current understandings of time if we still using "time" bound language?

Great issue(s)! Two thoughts to consider: first, it may not be obvious that all language is time-bound or tensed. The sentence 'two plus two equals four' or 'squares are four sided' might be interpreted as tensed (both sentences were true on Monday, and on Tuesday, etc) but they may also be understood as tenseless (their truth does not depend on temporality unlike the sentence uttered by me 'I am writing in response to your question now'). Second, I suggest that we can have interesting, competing philosophical theories of time when we look at the meaning of what you are calling "time bound language." So, for example, those who embrace what is often called four dimensionalism, treat all times as equally real. On this view, the French Revolution is occurring in 1789, and that is as real as the Battle of Waterloo which is occurring in June of 1815 and my writing you a reply in 2012. According to what is sometimes called presentism, only the present is real, so while it is true that the French Revolution occurred in 1789, that is past and it is not (in some fashion) still going on in 1789. Four dimensionalism winds up making time out to be akin to space and treats temporal objects as containing temporal parts (just as, for example, a week consists of seven days, it might be said of a person, that she consists of, say, a lifetime of N number of years), whereas presentists think of temporal objects as either fully and entirely present or not (on this view, you are fully and wholly present now, and not just a time slice of your lifetime as a whole). Check out the free online Stanford Encyclopedia of Philosophy on time for engaging arguments and sources.

Some people say that time only began when the universe began. I think that is

Some people say that time only began when the universe began. I think that is because they equate time with movement. I disagree. I think that time is measured by movement but it isn't movement per se. I think that time is that ever present hypothetical or actual possibility of change. I hope that makes sense. What says you philosophers?

At least movement is relatively clear, and in principle perceivable. But what is a "hypothetical or actual possibility of change"? (Are you distinguishing two different kinds of possibility here, one hypothetical, the other actual, or does this phrase somehow refer to one thing?) ... You'd need a rather thorough account of what "possibilities" are, in particular non-actual possibilities, to make this answer be an improvement on the earlier one .... (You might read Augustine's famous treatment of time, where he explores the relationship between time and motion: in his Confessions, ch. 11 .....)

hope that's a start!


It is said that even a broken clock is right twice a day.

It is said that even a broken clock is right twice a day. But can we actually say that a broken clock correctly tells the time twice a day? Wouldn't that require the clock, in some way, accomplishing some process that attempts to tell the time, and being successful twice? It seems to me that a broken clock can't be said to be correct at all, since it isn't even trying. For sake of analogy, if I ask someone a trivia yes-no question, and they decide their answer by flipping a coin, are they correct if the coin happens to give them the right answer?

good question!

perhaps distingish between our being justified in using the device for its purpose from its actually succeeding in fulfilling its purpose. in your coin case you would not be justified in believing the answer the coin gives -- but the answer might (luckily) actually be correct. similarly for the clock case -- its being broken means you are not justified in using it to learn the time, but sometimes unjustifiable processes do yield the correct result (even though you're not justified in believing it) -- so on this view the clock IS right twice a day ....

hope that helps


Is the concept of backward causation coherent and is it really taken seriously

Is the concept of backward causation coherent and is it really taken seriously by philosophers? I doubt whether any scientist would accept the idea and I would like to know what you think.

Is the idea of backwards causation coherent? It seems not, as you could, for example, cause earlier events, such as your own birth, not to have happened. There is also the famous "bilking" (cheating) argument due to Max Black, according to which you can prevent the future cause of something that has already happened from occurring. All the same, philosophers, particularly Michael Dummett, have taken the idea perfectly seriously, and defended it. You write that you doubt that a scientist would take the idea seriously, but plenty of physicists, including Richard Feynman, have indeed used the idea for a variety of purposes, including the remarkable idea of positrons running backwards in time.

When people claim that in "non-Western cultures, time is cyclical rather than

When people claim that in "non-Western cultures, time is cyclical rather than linear", what do they mean by this? Is this nothing more than another way of stating the truism that history repeats itself? It seems that even within cycles, there must be linearity of some kind - consider for example the carbon cycle, where the cycle is little more than a repeating linear loop. Throughout my life, I have only ever been growing older, and I will not suddenly be young again - or start getting younger - when I stop aging. So what does it mean to say that time is cyclical and not linear?

I have nothing to add here except to say that this question has often occurred to me -- has anyone truly believed (say) that when spring rolls around each year, it is precisely the very same "time" that it was the year before, rather than being merely a "similar" environment recurring? I suppose if something like Nietzsche's 'eternal recurrence' were the case (taken literally), then there could be some question of a genuinely recurring ie cyclical time -- but even then wouldn't it be far more plausible to hold that time remains linear even if the events occurring in time might go through cycles?

Will be curious if anyone else weighs in with an endorsement of the opposing view -- or even of the claim that any culture has endorsed such a view.

best, ap

Are historical facts always true, throughout time?

Are historical facts always true, throughout time? Consider the fact that Barack Obama is the forty-fourth president of the United States of America. Was it true two hundred years ago? If someone in the nineteenth century had said "Barack Obama is the forty-fourth president of the United States of America", would it have been true?

This is an excellent question and one that is much debated historically and today. It has implications about freedom and determinism, logic, and the philosophy of God, good and evil. It seems that classical logic requires that propositions are either true or false. "Barack Obama is the forty-fourth president of the USA" appears to be a proposition. And we have found it to be true. But in that case, it seems that Obama could not have failed to have won the election against McCain. It has seemed to some (but certainly not all) philosophers that this would mean Obama's election was fixed in some sense, perhaps determined. Some who worry about this problem are theists who think that if God knows from eternity that in August of 2011 you would ask your question, then there is no possibility that you would not have typed in and submitted your question to Askphilosophers. For many theists, it is vital to affirm that creatures / human beings have free agency, otherwise it would seem that God has determined humans to be evil. The other worry about what is called future free contingents (the fancy term for propositions that refer to future events that appear to involve freedom and contingency) has to do with whether there even could be such future propositions. It seems that for a proposition to be true there must be SOMETHING in virtue of which the proposition is true. But in the 19th century, Obama did not exist; he did not exist then, nor was he existing in the 21st century. From this line of reasoning (which was probably Aristotle's), we should hold that propositions involving future free contingents are neither true nor false. Theists who take this position (like Richard Swinburne) contend that even an omniscient God does not know about future free continents. According to Swinburne, God knows all possible truths and because propositions about future free contingents is neither true nor false and thus cannot (by definition) be known by any being of any kind, such propositions about the future are not the sort of thing that even God knows.

I asked this question of a physicist and he told me to ask a philosopher. If

I asked this question of a physicist and he told me to ask a philosopher. If one was to observe a closed, isolated region of space under vacuum conditions, i.e. there are no particles in this region and none may enter into it. Also there are no fields (i.e. gravitational, electromagnetic, etc.) acting or existing on or in this region. The only interaction with this system is as an outside observer. Can this observer notice the passing of time? If so, how? And does the act of observation make the observer part of the system, since the observer is technically interacting with it? Currently we measure time by the movement of quantum mechanical particles, such as the molecules in a ticking clock; the vibrations of atoms; and the decay of radioactive isotopes. But could we perhaps, in this hypothetical system, justify using properties of space itself, such as quantum foam or the expansion of space (expanding universe), and, if so, how would we observe these features?

Thank you for your question. Let me touch it up just a bit:

There are no gravitational fields in general relativity over and above the curvature of space(time). In the spirit of the question, I will assume that the spacetime geometry is unchanging.

An observer might be able to notice the passing of time in lots of ways (e.g., from his own heartbeats or passing thoughts or wristwatch). I presume that the question is asking whether the observer could notice it on the basis of some observed changes in the region of space in question.

I am inclined to think not. Nothing is changing there. If spacetime geometry were changing, then the passage of light through the region to us would betray the change to us. But the question stipulates that nothing passes through the region.

If time is infinite does this give us any hope for life after death? After all

If time is infinite does this give us any hope for life after death? After all if time is infinite, it is inevitable that all the cells in my body (my DNA etc) will be reconstructed in some far off day and age.

I'm not quite ready to go along with my colleague's answer, but my answer isn't any more hopeful.

If time has the structure of the real line (as we usually think) then even if it's infinite, every moment is only a finite time away from now. (Compare: every real number is only a finite distance from 0.)

But even if time is infinite in the way the real number line is, it doesn't follow that there will be a duplicate of you somewhere off in the future. To get that conclusion woud take a lot of extra and optional premises. More important, even if there will be a duplicate of you someday, there's no good reason to think it would be you, nor is there any good reason to think that you could look forward to its experiences. (These two aren't quite the same issue, as it turns out.)

Clearly there's a lot in the background here. If you're interested in more reading on the core problem, i.e., the problem personal identity, you might have a look at Martin and Barresi's anthology, called Personal Identity.