- #1
arcturus12453
- 3
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I have a question, but I am not sure how to express it.
I have been thinking about the idea of the universe as a four-dimensional object, with time as just another dimension. I have also been thinking about David Deutsch's idea of the universe as a sequence of quantized slices or slides.
People usually think of causality as an active phenomenon - one thing causes another to happen.
But both these analogies seem to question the necessity of causality. Why should one "slice/slide" of the universe have any relation to the one before it or after it? Why should a four-dimensional universe have a kind of continuity and relatedness in its contents across the time dimension?
When we drop a ball from a tower, the ball hits the ground. But viewed four-dimensionally, the ball in the future was already on the ground. If the past and future are both physically real, then there is no necessity in having a relation between them. The ball you dropped could have fallen up, or disappeared, or turned into a pot of geraniums.
This is kind of backing into the question of why physical causal laws exist - the physical causal laws describe the apparently already-existing relation between things in temporal sequences. But why is there any relation at all? There doesn't seem to be any need for there to be.
If time is really just a dimension, and there is no "meta-time" as Deutsch puts it, then causality is not really an 'active' force that causes things to be the way they are - it is more like a kind of tautological description of the way things happen to be. But the way things happen to be LOOKS very 'causal', and just happens to be easily describable by 'laws' of connections across time.
Are there any theories about why causality appears? Or is it possibly even an illusion? That is, we are in a "slice/slide" of the universe, the past or future sequence might be an illusion and not exist. Or am I missing something?
Arc
I have been thinking about the idea of the universe as a four-dimensional object, with time as just another dimension. I have also been thinking about David Deutsch's idea of the universe as a sequence of quantized slices or slides.
People usually think of causality as an active phenomenon - one thing causes another to happen.
But both these analogies seem to question the necessity of causality. Why should one "slice/slide" of the universe have any relation to the one before it or after it? Why should a four-dimensional universe have a kind of continuity and relatedness in its contents across the time dimension?
When we drop a ball from a tower, the ball hits the ground. But viewed four-dimensionally, the ball in the future was already on the ground. If the past and future are both physically real, then there is no necessity in having a relation between them. The ball you dropped could have fallen up, or disappeared, or turned into a pot of geraniums.
This is kind of backing into the question of why physical causal laws exist - the physical causal laws describe the apparently already-existing relation between things in temporal sequences. But why is there any relation at all? There doesn't seem to be any need for there to be.
If time is really just a dimension, and there is no "meta-time" as Deutsch puts it, then causality is not really an 'active' force that causes things to be the way they are - it is more like a kind of tautological description of the way things happen to be. But the way things happen to be LOOKS very 'causal', and just happens to be easily describable by 'laws' of connections across time.
Are there any theories about why causality appears? Or is it possibly even an illusion? That is, we are in a "slice/slide" of the universe, the past or future sequence might be an illusion and not exist. Or am I missing something?
Arc