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Time
Does only the present exist?
It feels obvious that only the present is real. The past is gone. The future has not happened yet. That view is called presentism: reality is one thin slice, and the slice moves.
But physics complicates it. Einstein's relativity suggests there is no single “now” that everyone in the universe shares. That pushes many philosophers to eternalism, sometimes called the block universe: past, present and future all exist equally, like frames of a film laid out side by side. “Now” just means “where I am in the block”, like “here” means where I am in space.
Try it · Each slice is one moment of a ball moving in a circle. Pick a theory and move “now” along the timeline.
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A middle option is the growing block: the past and present exist, the future does not yet, and the block of reality keeps growing as new moments are added.
On the block view, a moving ball is really a long 4D “worm” stretched through time. Each moment of the ball is one slice of the worm.
Key ideas
Words worth remembering
- Presentism
- Only the present moment exists.
- Growing block
- Past and present exist; the future does not yet.
- Eternalism
- Past, present and future all exist equally, as one block.
Think about it
If eternalism is true, is your 10-year-old self still, in some sense, out there?