"The Unreality of Time" (1908) - McTaggart

John McTaggart Ellis McTaggart (September 3, 1866 – January 18, 1925) was an Idealist metaphysician. For most of his life McTaggart was a lecturer at Trinity College, Cambridge. He was considered one of England's leading Hegel scholars at the beginning of the 20th century and among the most notable of the British Idealists.

"The Unreality of Time" (1908) - McTaggart



In The Unreality of Time (1908), the work for which he is best known today, McTaggart argued that our perception of time is an illusion, and that time itself is merely ideal. He introduced the notions of the "A series" and "B series" interpretations of time, representing two different ways that events in time can be arranged. The A series corresponds to our everyday notions of past, present, and future. The A series is "the series of positions running from the far past through the near past to the present, and then from the present to the near future and the far future" (p. 458). This is contrasted with the B series, in which positions are ordered from earlier to later, i.e. the series running from earlier to later moments.


McTaggart argued that the A series was a necessary component of any full theory of time, but that it was also self-contradictory and that our perception of time was therefore an ultimately incoherent illusion.

The Necessity of the A series
The first, and longer, part of McTaggart's argument is his affirmative answer to the question "whether it is essential to the reality of time that its events should form an A series as well as a B series" (p. 458). Broadly, McTaggart argues that if events are not ordered by an A as well as a B series then there cannot be said to be change. At the centre of his argument is the example of the death of Queen Anne. This event is a death, it has certain causes and certain effects, it is later than the death of Queen Elizabeth etc., but none of these properties change over time. Only in one respect does the event change:

"It began by being a future event. It became every moment an event in the nearer future. At last it was a present event. Then it became past, and will always remain so, though every moment it becomes further and further past. Thus we seem forced to the conclusion that all change is only a change in the characteristics imparted at to events by their presence in the A series" (p. 460).
Despite its power and originality this half of McTaggart's argument has, historically, received less attention than the second half.


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The Incoherence of the A series
What is most often presented as McTaggart's attempted incoherence of the A series (the argument of pages 468-9) appears in the original paper only as a single part of a broader argument for this conclusion, but it can be extended to have general application. According to the argument, the contradiction in our perception of time is that all events exemplify all three of the properties of the A-series, viz. being past, present and future. The obvious response is that while exemplifying all three properties at some time, no event exemplifies all three at once, no event is past, present, and future. A single event is present, has been future, will be past, and here there is, it seems, no contradiction.

McTaggart's great insight is that this ascent will apparently give rise to a 'vicious circle' or 'vicious infinite series'. On the one hand, the response depends upon the A-series to make sense. To distinguish the properties of being present, having been future and going to be past requires a conception of time divided into past, present and future, and hence of the A-series.

"Accordingly the A series has to be pre-supposed in order to account for the A series. And this is clearly a vicious circle" (p. 468).
The same difficulty can be represented as a 'vicious infinite series'. One can construe the response above as "constructing a second A series, within which the first falls, in the same way in which events fall within the first" (p. 469). But even if the idea of a second A series within which the first falls makes sense (and McTaggart doubts it does, p. 469), it will face the same contradiction. And so, we must construct a third A series within which the second falls. And this will require the construction of a fourth A series and so on ad infinitum. At any given stage the contradiction will appear; however far we go in constructing A series, each A series will be, without reference to a further A series containing it, contradictory. One ought to conclude, therefore, that the A series is indeed contradictory and, therefore, does not exist.