Kelwin asked:

Where is time?

Answer by Jürgen Lawrenz

Wrong question. Time is not anywhere. Rather, it is an abstract name we give to the sum of all occurrences in the universe.

To follow this, conceive of the universe as a space with contents, all of them motionless objects. It is hard to envision this, because (for a start) there could be no stars. But as it happens, there is a also a residual potential in the objects, as some of them possess characteristics which conflict with the characteristics of their neighbours. For ease of reference, think of magnets which can either attract or repel each other. If two such objects physically repel each other, there is evidently something happening that will have consequences. Namely that each is going to be propelled into a different neighbourhood, where the same thing might happen again.

What you witness here is a succession of events. In due course, many of these will occur simultaneously; but on the whole the nature of succession is such that some events occur before and others after those which are simultaneous. Further, as the objects in the universe range from extremely small to extremely large, the succession of events is complicated by the duration which objects of different magnitude require to complete a specific occurrence.

We humans possess an innate sense of succession, based on the fact that as we age, our bodies keep changing. In addition, we have to make many voluntary changes of locality, some of which may take us a long way from home — such as shopping for food. While we do this, many other people do things at the same time, others have already done and yet others will do later.

As we humans are social creatures and also depend on many occurrences in the natural world for the organisation of our lives, we started looking at ways of assessing all the events which we can witness, in terms of human events. Some occur in the blinking of an eyelid or the flash of a lightning; others may transpire from sunrise to sunset; yet others in accordance with the seasons; and so on. And now, at some juncture in human history, people set about elaborating a system of occurrences and tied them to these observable natural phenomena. Very recently — after the invention of mechanical clocks — that system acquired the form which we still maintain today: whereby a day is divided into 24 hours, which in turn have 60 minutes, while they each have 60 seconds; and on the other side 7 days a week, 365 days for a set of 4 seasons; as well as some astronomical nomenclatures.

So you can see from this that time is not a thing, nor an event, nor a location: indeed nothing at all. It is a gauge devised by humans to correlate occurrences in the world to make them intelligible to ourselves in terms of past, present and future. In other words, it is a creation of the human intellect. Accordingly it does not make much sense to speak of time as if it were an existent in itself. It is a human invention, and has no relevance to any existent other than ourselves.

So as not to disregard one other issue: Science (still done by humans!) is of course obliged to work on a definition of time which purports to be an absolutely objective. But as we pry deeper and deeper into the subnuclear realm, this brings defects of the system to the fore in the apparent ‘travel backward in time’ of some phenomena. Richard Feynman used to say to his students, ‘don’t worry about it — as long as the equations work out, everything is fine!’ I make mention of this, because time travel is such a fashionable topic today, as if such events could be magnified into our common time scales without being cranked into the succession/simultaneity factor. Whereas (as I said) it simply reveals a flaw in the system; and it helps to understand this simple issue so as to get out of the rut of believing things that don’t pertain or exist, just because some mathematical equation in an almost inconceivably small dimension ‘comes out right’ that way!