How should we conceive of time? The question admits no easy answer, so different cultures have developed different time conceptions. The nature of time is something of a philosophical rabbit hole – I’ll try staying away from scholarly debates on time, instead focusing on the way ordinary people ‘feel’ time. What picture does the word ’time’ elicit?

In the West today, most people conceive of time as linear: time moves in a straight line, just like an arrow through space. Hence we represent time as lines – timelines.

In discourse on AI, believers in the transformative impact of AI (myself included) seem to assume a special conception of time. I think AI will lead to rapid technological progress and economic growth within the next few decades, and this could – though not necessarily – lead to accelerated social and technological progress.

Will MacAskill and Finn Moorehouse introduced the thought experiment of the accelerated decade to make the potential consequences of AI more visceral: imagine all scientific, technological, social and political progress from 1925-2025 occurring in the period 1935 – AI might catalyse the same kind of dizzying progress in the next decade. Implicit in their thought experiment is an event-driven conception of time: something happens around 2020-2040 (an intelligence explosion), which compresses the rest of the timeline.

My conception of time has influenced as series of big life decisions, so I wanted to inventory common time conceptions out there. As we shall see, our linear conception of time is a fairly recent phenomenon, and alternatives exist.

Some time conceptions #

For most of Western history, the notion of circular time dominated. In a circular time conception, our lives – and history more broadly – are viewed as a succession of repeated events, e.g. the four seasons or periods of war and peace. Plato introduced a circular time conception in Timaeus, linking time to planetary orbits¹. The idea of reincarnation, implicit in Eastern thought traditions, also suggests a circular view of time.

By the late 19th century, a linear time conception took hold. Emily Thomas gives four explanations to this shift in perspective.

These are all fun facts, so I’ll quickly rehash her views. First, there was the creation of time tables and timelines – if you want to visualise historical events, you can’t use circles – you have to use tables or lines. Second, there was Darwin’s theory of evolution (Darwin is everywhere). Third, she points to the development of chronophotography, a photographic technique which captures movements as a series of snapshots. Finally, physics: Charles Hinton developed a physical theory of time as a fourth dimension. From this perspective, then, time really was a line.

But other explanations are possible. You could also highlight the influence of Christianity. In the Bible, there’s a beginning and an end: Jenesis and Judgement Day. Time moves from beginning to end – time is linear.

As a special case of linear time, we can also speak of ‘binary time’², where you chop time into two distinct epochs. For example, some environmentalists distinguish between the pre- and post-anthropocentric era. Likewise, if you believe AGI could be huge, you might think in terms of pre- and post-AGI eras. Or, for a communist, the revolution marks a turning point in history.

Alternatives to linear and circular time exist. For example, Parmenides and Zeno viewed time as an illusion. Kant held a similar view, it seems. Or you could just be agnostic about your view of time. From Four Quartets:

Time present and time past Are both perhaps present in time future, And time future contained in time past.

Maybe one should just admit defeat?

Conclusions #

So much so for our overview of time conceptions. One conclusion emerges from these examples: your time conception is closely connected to your worldview. In a secularised society, a proxy question for ‘Do you believe in some God?’ might be ‘How do you view time?’ Sometimes you want to think outside the line.