Periods, Intervals and Events

Time measures duration, periods and intervals, doesn’t it?

This idea of time being irrelevant to an isolated set is hard to grasp when all around us we apparently see ‘time passing’. If I want to know how long my daily jog is, I start my stop-watch at the beginning of my jog, and stop my stop-watch when I finish. And this tells me how much time have I taken to complete my jog.

So is time measuring the period of my jog? Or am I measuring the time taken for my jog? Or do we use time to measure the time of my jog? I think we use time in different ways, and it can mean both the period being measured and the unit of measurement.

As we’ve already argued, time can’t measure time. Isn’t this rather confusing? It’s certainly unhelpful when trying to consider what time is. Maybe we should say “I am measuring the duration of my run using a unit of calibration based on a regular event-series”, which keeps time out of it.

But does it? Duration is a reference to time? Duration, period and interval are all amounts of time. Duration is “the length of time something continues or exists” according to A period has several references to time in its different definitions, including an interval of time, and a round of time by which time is measured. And interval is an intervening period of time (we’ve already mentioned that circularity is a problem in defining time, but there is something about each of these words constituting an amount of time).

Again we have a reference to an amount of time. Doesn’t that edge us closer to the idea that time IS a thing, a concrete noun, something tangible?

Well, if only the self-same dictionary could offer us a more fulsome explanation to what this ‘time’ that duration, period and interval are an amount of actually is. To offer a definition of something (period) in terms of something else (time) that is so inadequately described, is not helpful.

But as we have broken down the meaning of time as used in a variety of dictionaries ourselves, let’s use our own definitions. We have the two definitions; a framework and a collective of events:-

Can period be referring to the abstract framework definition of time? Is period an amount of the abstract framework? Well, it’s an abstract, so how can anything be an amount of it.

So, period being an amount of time must be referring to the use of time as a mass noun – a collective term for a non-specific set of events. Period is actually giving us a subset of events. Could period be referring to a non-specific set of events?

This makes sense. The period from the beginning of my jog to the end of my jog is specified by the events of me starting my jog and me finishing my jog. And it is calibrated by reference to the earth’s motion during my run. The earth rotated for 1/48th of a complete cycle if I did a 30-minute jog.

So period, duration and interval are therefore calibrated by reference to an (external) event-series; hence can they be explained without the need for time? It’s worth taking a closer look, as this is important.


A period is a slippery idea. It is defined in various, straight-forward ways:- as a quantity of time, or as a round of time, or an interval of time. This seems simple enough, surely.

But as we don’t know what time is, how meaningful are these simple definitions?

Well if we can’t define period in terms of time (because we don’t know what time is) how do we define it?

A period must have a beginning and an end. And these two events (the beginning and the end) are the determiner of the period – the reference frame. So the beginning event, the period and the ending event form a discrete set. And, for that set, there is no change between the first event and the last (there can’t be, there are only two events in this set). So time is irrelevant to this set, UNLESS and until you calibrate the period using an external calibration (e.g. the earth’s rotation). But this external calibration confers no intrinsic “Time” on the period. The set (event one, period, event two – out reference frame) is static and hence timeless until an external calibration is imposed around it.

In other words, for a discrete reference frame (the set to whom the beginning event and the end event belong), period is irrelevant – when this set is viewed in isolation (e.g. our static object above). There is nothing between the beginning of the period and the end, by definition. Time is therefore meaningless.

It’s only when you calibrate this gap between the two events by reference to an external event-series that it is given a “quantity” definition; and even then this quantity definition confers no impact or intrinsic quality on the discrete set itself. ‘Time’ only matters to the external event-series – it’s just a relative calibration exercise.

It’s accepting the idea that period does not have a universal application, that it refers only to a discrete set, and is hence isolated from external “time” until this is referenced which is the hard part to grasp here.


The same conundrum occurs for interval as for period. In fact interval can be defined as the period between two events. There is an implied assumption that two events must have an interval between them. But for a specific object in a closed environment (single reference frame), where the object hasn’t altered state (i.e. changed) between the two events (and it hasn’t else we would reference the intermediate event) then there is no interval (i.e. no time lapse) UNTIL an external calibrator references the interval. Time doesn’t ‘exist’ in the closed environment if there is no change, and change happens at events. Hence between two events, when nothing is happening, time doesn’t have anything to measure, so it doesn’t ‘exist’.

It’s only when the environment is opened up, and external changes are referenced, and hence calibration appears, that the non-event period of the initial closed object is then measured by reference to external change.  We could say that time is allowed to ‘infiltrate’ this closed environment.

This is a crucial notion in the understanding of time. Take the example, say, of a diamond, formed millions of years ago. And it has sat, unchanged (barely weathered) for millions of years. Has time passed for it? The question should really be ‘has change happened to it’.

Well, no, it hasn’t. For the diamond alone, time has not passed. Sure, the earth had spun on its axis several million times, so yes there has been many events that have happened in the world around the diamond. So in relative terms we might say ‘time has passed’ or more accurately we mean external events have happened around the diamond. But for the diamond on its own there has been no ‘time passage’ – nothing has happened to it. It is indistinguishable from the diamond a million years ago. Time is only relevant when the events of the world outside are used to measure against the rock itself.

This means there is no such thing as interval, when we talk about a single unchanging object (the diamond) alone. Time is irrelevant to a single object between its own events. Time is reference frame specific.

The reason this is crucial is that this dismisses the need for a ‘universal time’. People suppose that although the diamond has been unchanged for millions of year, the ‘passage of time’ is proven because the two events (the formation of the rock, and ‘now’) have an interval.

Well, they don’t – only external events create (i.e. calibrate) the ‘interval’. There is no impact of time on eth the diamond, it hasn’t changed. For the diamond, time is irrelevant. Universal time (as a concrete phenomenon) ceases to have any meaning – only individual change-events matter.

Persistence and existence

I have used the term ‘interval’ to express the period between two change events for a specific object.

There is also a term used to supposedly express the sense of times universality which is persistence. It essentially refers to the same idea as my use of interval – but refers to an intrinsic property of the object – that of existence.

The argument in a nutshell is that an object exists (between change events). It hence exists in a ‘time period’, i.e. it has ‘persistence’ – its existence beyond an instant requires time for that existence to occur in; hence ‘time periods’ has validity as a dimension of a concrete phenomenon, hence time is universal and necessary. This is an easy place to arrive at – we all think it – we see time ‘happening’.

But it is a fundamentally flawed perception and conclusion. Persistence is a meaningless condition. A static, non-changing object simply exists. Time has NO intrinsic effect on, impact on or relevance to it. But people can’t shake the idea that ‘time passing’ is some universal ‘flow’, which effects all things equally. The idea that to exist an object must exist ‘in time’ is the universal misunderstanding.

Persistence is related to a single object or reference frame; if this single object is unchanging, persistence is meaningless until and unless external calibration is introduced to quantify it. But the quantification is the external events series (a clock ticking, the earth spinning) calibration. It has NO intrinsic relationship with our static, single object, which just sits, unchanging, unaffected. Time does NOT exist for that object. Only an external relativity imposes an external structure of time calibration on it. A static, unchanging object simply is…time is irrelevant to it (you could say ‘it’s timeless’).

This is the crux of understanding time. If you understand that time doesn’t ‘pass’, only events happen; and that to a static, unchanging object, time is irrelevant (until you use external events to calibrate) then time as a universal ‘thing’ ceases to have any necessity or meaning.

In other words, persistence (existence, if you like, i.e. needing time in which to be) is wholly meaningless. Unhelpfully it infers the ‘dimension/tunnel/flow/universality’ notion of time that is the illusory confidence trickster stymying most people’s ability to understand the simple, subtle reality of time’s abstractness, its non-existence.

This is difficult for people to grasp. Something that is static and unchanging is wholly unaffected by time. People want there to be this universal ‘flow’ that is constantly passing by – they can’t get past the idea that a static object is somehow enduring time ceaselessly. Time passes, surely?