Causality
Was thinking about a conversation that I had had with Robert Elliot at the University of New England. I mentioned to him something I had read a long time ago in The Science in Science Fiction by Peter Nicholls. It was the Principle of Causality, stating, essentially, that effects happen after causes. This was the basic problem with travelling backwards through time, that it would violate the principle of causality. Robert said he thought that that was just a prejudice. He saw a cause as an engine that created an effect, which could just as easily occur in the past as in the future. Well, I know that the Principle of Causality is a cornerstone of physics, and I don't really think that it is a prejudice. I think it would be a prejudice if physicists were trying to define causes in terms of temporal position, but they are not. Their claim that effects happen after causes is a posteriori, not a priori.
He went on to talk about what logically consistent time travel is. Basically, it's quite different from the kind of thing you get in Back to the Future, where you can change the present by going back and changing the past. The idea is that the past can never change, even if events in the present can cause events in the past. Yeah, I remember the same thing being stated dogmatically in The Metaphysics of Star Trek by Rick Hanley. I think it begs the question in favour of one particular idea of time travel, but that's another story.
So I was reading about quantum entanglement. And I happened to be also thinking about causes as engines that created effects, independent of their position in time relative to the causes. We all know how causes can create effects in the future. The idea that causes can create effects in the past has long been the stuff of science fiction. But what if causes also created effects in the present, say, independent of their position in space?
I mean, quantum entanglement is one of the weirdest aspects of quantum mechanics. The idea that two particles, once entangled, can continue to influence each other, no matter how far apart they are. The value that a measurement creates on one will create a correlated one on the other. The transfer in information between the two quantum states has been shown to be at least a thousand times faster than light. And the reality is that we do not know what the upper limit is on the speed of the transfer.
So I figure, what if this is because the speed is infinite, i.e. because the "transfer" is instantaneous? This is explained if causes can create effects in the present. Presumably influences that are not necessarily causal - because they can be probabilistic - can also create effects in the present. (Just in case anybody has a problem with the way I am using the word "cause".) Yes, it's a violation of the Principle of Causality, but at least causes still cannot be seen to have created effects in the past (yet?).
He went on to talk about what logically consistent time travel is. Basically, it's quite different from the kind of thing you get in Back to the Future, where you can change the present by going back and changing the past. The idea is that the past can never change, even if events in the present can cause events in the past. Yeah, I remember the same thing being stated dogmatically in The Metaphysics of Star Trek by Rick Hanley. I think it begs the question in favour of one particular idea of time travel, but that's another story.
So I was reading about quantum entanglement. And I happened to be also thinking about causes as engines that created effects, independent of their position in time relative to the causes. We all know how causes can create effects in the future. The idea that causes can create effects in the past has long been the stuff of science fiction. But what if causes also created effects in the present, say, independent of their position in space?
I mean, quantum entanglement is one of the weirdest aspects of quantum mechanics. The idea that two particles, once entangled, can continue to influence each other, no matter how far apart they are. The value that a measurement creates on one will create a correlated one on the other. The transfer in information between the two quantum states has been shown to be at least a thousand times faster than light. And the reality is that we do not know what the upper limit is on the speed of the transfer.
So I figure, what if this is because the speed is infinite, i.e. because the "transfer" is instantaneous? This is explained if causes can create effects in the present. Presumably influences that are not necessarily causal - because they can be probabilistic - can also create effects in the present. (Just in case anybody has a problem with the way I am using the word "cause".) Yes, it's a violation of the Principle of Causality, but at least causes still cannot be seen to have created effects in the past (yet?).
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