Great IdeasNature and science
Time
What time is, and whether the world had a beginning.
The question
What is time? Did the world have a beginning, and why does time feel so different at different moments?
How the books answer
Oldest first. Each stop is our own short summary of what the author argued; follow the link to the rung for the whole lesson.
c. 360 BC
Plato, Timaeus and Critias
Plato calls time a moving image of eternity. The maker set the sun, moon and planets moving so that their regular cycles would measure days, months and years. Time and the heavens began together.
c. 350–322 BC
Aristotle, Physics
Aristotle defines time as the number of motion with respect to before and after. Without change, we would not notice time passing. He held that time and motion have no beginning and no end.
c. AD 397–400
Augustine of Hippo, The Confessions
Augustine famously says he knows what time is until someone asks him. The past is no longer and the future not yet, so where is time? He concludes that time lives in the mind as memory, attention and expectation, and that God created time along with the world.
1265–1274 (unfinished)
Thomas Aquinas, Summa Theologica, First Part
Aquinas asks whether the world always existed. He argues that reason alone cannot prove either answer, so the question can't be settled by philosophy. He believed, by faith, that the world had a beginning.
published 1609
William Shakespeare, Sonnets
Shakespeare's sonnets battle devouring Time, which wrinkles faces and topples monuments. Their answer is love and poetry, which can outlast it. The lines still live, as he promised.
“Rough winds do shake the darling buds of May, And summer's lease hath all too short a date: ...”
1781; second edition 1787
Immanuel Kant, The Critique of Pure Reason
Kant argues that time is not a thing out in the world but a form of our own experience. We can't experience anything except in time. He also shows that reason gets tangled when it asks whether the world had a beginning in time.
1903
Henri Bergson, An Introduction to Metaphysics
Bergson separates clock time, cut into equal pieces, from lived time, which flows and builds up like a melody. Science measures the first, he says, but we know the second from inside, by intuition.
“The first implies that we move round the object; the second that we enter into it.”
1913
Marcel Proust, Swann in Love (from Swann's Way)
Proust writes about time lost and found. In Swann in Love, a phrase of music is tied to a season of feeling that Swann later meets again. Memory, for Proust, can bring the past back whole.
“For a long time I used to go to bed early.”
1916 (English 1920)
Albert Einstein, Relativity: The Special and the General Theory
Einstein shows that time is not the same for everyone. Two events that are simultaneous for one observer may not be for another moving past. Clocks that move run slow, which has since been measured with precise clocks on airplanes and satellites.
“Every reference-body (co-ordinate system) has its own particular time; unless we are told the reference-body to which the statement of time refers, there is no meaning in a statement of the time of an event.”
1927
Virginia Woolf, To the Lighthouse
In the middle part of To the Lighthouse, called Time Passes, ten years go by in a few pages while an empty house slowly decays. The rest of the novel stretches single days across many pages. Woolf shows how differently time feels from outside and inside.
For young readers
Time is what clocks measure: seconds, minutes, days. But time feels different at different moments. Waiting for your birthday feels so slow, and a fun afternoon zips by!
Augustine said he knew what time was until someone asked him to explain it. Try it yourself: can you say what time is without using the word 'time'?
Talk about it
- When does time feel slow for you? When does it feel fast?
- Augustine says the past lives in memory and the future in expectation. What do you think?
- If you could visit any time in the past, when would you go?
- Einstein said moving clocks run slow. Does that surprise you?
- Shakespeare hoped his poems would beat time. What do you hope will last?
Where else on the site
- Time Dilation
- The Relativity of Simultaneity
- Solar and Sidereal Days
- Time: chron, temp, ann and nov
- Fleeting and Lasting
- Waiting and Hurrying
Every rung tagged with this idea:
These pages are our own short synthesis, written for families. They were inspired by Mortimer J. Adler's Syntopicon, the index of great ideas in volumes 1 and 2 of Great Books of the Western World, but the questions, summaries and groupings are ours, not the Syntopicon's. Short excerpts come from public-domain translations, credited where they appear.