There are plenty of reasons to be skeptical of the Apple Watch. Who wants to use a touchscreen that tiny? Why would I want to send my heartbeat to my friends? Why should people who aren't titans of finance spend $349 (the cost of the cheapest model) on a watch?

But the best reason for skepticism is that it's, at root, a watch, with the primary purpose of telling time. And time is an illusion.*

The unreality of time

While arguments against the existence of time date back at least to the pre-Socratic Greek philosopher Parmenides, it was first comprehensively laid out in its modern form in the Cambridge philosopher J.M.E. McTaggart's 1908 article in Mind, "The Unreality of Time." McTaggart's argument boils down to an observation about how we talk about the past, the present, and the future. Every event, he notes, is said to be in the past, in the present, and in the future, at various points of time. Those are contradictory descriptions. Something can't both be in the past and the future anymore than it can be both green and purple. Because time requires events to have contradicting descriptions like these, it's an incoherent concept and can't exist.

"That's nonsense!" I hear you saying. "Every event is in the future, then in the present, then in the past. It's never all three at the same time." It's the obvious rejoinder, but note what you're doing there. You're saying the same object can have different descriptions apply to it simultaneously because they apply to it at different times. You're presupposing the existence of "different times," of time itself. You're trying to prove the existence of time by asserting that time exists. That's cheating.

Hugh Mellor, a present-day Cambridge philosopher who thinks that time exists in some sense but agrees with McTaggart's critique, put it well in his book Real Time II: statements about an event, e, like "'e is past', 'e is present', and 'e is future'…cannot consistently be made true when they are true by e's having the properties of being past, present, and future." This conception of time is circular.

It also leads to an infinite regress. As the late Oxford philosopher Michael Dummett noted, the "it was past, is present, and will be future" reply implies that it will be true of all events at one point or another that they were past, are past, will be past, were present, are present, will be present, were future, are future, and will be future. And a bunch of those statements contradict each other; it can't be true that an event "will be future" and "will be past." You can reply and say they don't contradict each other because they're true at different points of time, but that just produces another jumble of contradictory statements ("is going to have been past," "was going to be future," etc.) and leaves us back where we started.

The ABCs of the philosophy of time

A better counterargument argues that "past/present/future" isn't the only way to think about time. McTaggart calls an ordering of events like this — in terms of how different times relate to the current one, from past to present to future — an "A series." Wake Forest's Adrian Bardon, author of the excellent A Brief History of the Philosophy of Time, also refers to A series as "clock time," since they represent time as continuously passing.

But you can think of other orderings. You could think about time by thinking about how different times relate to each other, rather than to the present. For example, you can say one event happened before another, or after it, or simultaneously. The difference is that, unlike the A series, you're not thinking in terms of how events relate to the present at all. An ordering like this — from earliest to earlier to later to latest — McTaggart calls a "B series" (Bardon also uses the term "calendar time").

Even simpler is a C series, which is, like a B series, an ordered list of events, without the proviso that the ordering means one event happened or will happen before another. It's just a list, without a clear meaning or direction.

Many philosophers of time who believe time exists have tried to argue that, while McTaggart's takedown of the A series conception of time may be correct, you don't need the A series for time to make sense. You just need the B series.

Against this, McTaggart argues that A series are fundamental to the notion of time. Time isn't time if there isn't a present, or if there isn't a direction in which events go. "The distinctions of past, present and future are essential to time and…if the distinctions are never true of reality, then no reality is in time," he writes. "Time, as we perceive it, always presents these distinctions." A B series isn't enough, because a simple listing of events in a given order doesn't allow for change. If one event is before another in the ordering, it will always be that way. The status of the event will never change. For things to change, an event can't merely come before or after another event; it has to go from being in the future to being in the present to being in the past.

McTaggart also notes that you can derive a B series by adding an A series to a C series. A C series on its own doesn't describe time, since it doesn't give a direction in which the events are supposed to go. That direction is given by an A series, which tells you how the events in the C series relate to the present. So while A series and C series descriptions of time are, McTaggart claims, fundamental, B series descriptions aren't. And if A series are fundamental, and contradict themselves, then something fundamental to time is incoherent, and time is a myth.

The passing of time is illusory

McTaggart's is a minority position in the philosophy of time these days. But his argument against the A series is widely accepted. While some people have chosen to respond to him by claiming that time is a basic feature of the universe that can't be explained in terms of other things — Western Washington University's Ned Markosian calls this the "Taking Tense Seriously" view, because it claims that tenses in language are fundamental and can't be explained in terms of anything else — the overwhelming majority of philosophers and physicists accept that there is no A series, no passing of time, and only a B series ordering of events across a fourth dimension of time.

"The B Theory is virtually the consensus position in both philosophy and physics," Bardon explains. "McTaggart's total rejection of the reality of time never had many defenders. But defenders of A Theory (realists about the passage of time) — once very common — have pretty much dried up too."

Some, like Markosian, continue to defend A Theory; Bardon notes that religious philosophers have a special interest in defending it, as its absence puts the concept of free will in jeopardy. B theory has other weird implications too, like the idea that things in the future can cause things to have happened in the past. While the B theory doesn't reject time outright, it "does not mean you get to have time the way you think you do," Bardon says.

Besides all the problems with A series McTaggart identified, many have argued that the theory of special relativity, by ruling out the possibility of events being truly simultaneous, makes A series impossible. "Most physicists feel the special theory of relativity (STR) pretty decisively demonstrates the relativity of simultaneity, and so what is 'present', 'past', etc depends on one's frame of reference," Bardon says. And if "past" "present" and "future" aren't objective, the A series can't exist.

Bardon brings up yet another problem with the A series. "If A Theory is right, then something is happening right now to the Battle of Waterloo: it it becoming 'more past," he notes. "I don't mean it's getting more past relative to us — rather, it is right now itself changing in terms of its pastness. That's the sort of nonsense you get from really attributing A-series properties to events."

Now, Bardon says, the big arguments within philosophy of time are about why it feels as though time is passing, even though it's not really. Clock time is an illusion— an illusion perpetuated by the Apple Watch.

* I do not believe time is an illusion. Sometimes it's fun to argue for positions you don't hold. Life is full of possibilities. That said, the passage of time is definitely an illusion for reasons explained above.