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CaseyTS t1_j0m42fo wrote

Reply to comment by snksleepy in Time is a Wheel, Time is an Arrow: on linear and cyclic conceptions of time by owlthatissuperb

Time literally is physical, like space or light. We can verify that experimentally, and we have. I recommend reading up on relativity.

The idea of cyclical time is completely theoretical.

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Matt5327 t1_j0m9mso wrote

More accurately, we can verify the accuracy of a model (general/special relativity) that treats it as physical. But even then, that model is incompatible with another successful model (QFT) which does not treat time as physical. So it continues to be a bit of an open question.

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CaseyTS t1_j0ma6ty wrote

You're right that general relativity and quantum mechanics aren't compatible at extremely high energies. We can verify that time is physical without using a model by making a physical experiment.

Consider a clock in space and a clock on earth. The clock on earth moves slower from the perspective of space, and the clock in space moves faster from the perspective of earth. That's a simple experiment that has been done plenty, and in fact, we have to account for that in satellites. This difference in time has clear physical features.

Time is physical. Our models about all areas of the universe, time and everything else, are not perfect. So maybe nothing is real and solipsism is the answer. Taking the existence of the physical universe for granted, time is physical, even if our models of it are not perfect.

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Matt5327 t1_j0makhd wrote

Saying time is physical is still a model of sorts, and without an extraordinarily broad definition of physical I would not agree that the experiment outlined suggests physicality.

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CaseyTS t1_j0manwh wrote

Have you studied physics for long?

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Matt5327 t1_j0mbmp6 wrote

Depends on what you mean by studied. I’m not going for a degree in it or anything, but I have been following research and engaging with physics education for about 15 years. But what does that matter? Let’s say physicists routinely use this extra broad definition of physical- that’s great for them, but their definition does not define it for other disciplines. So here we are in a philosophy subreddit, where we can reasonably expect something more narrow, so as to not automatically apply to any observable.

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CaseyTS t1_j0mcy6y wrote

> So here we are in a philosophy subreddit, where we can reasonably expect something more narrow, so as to not automatically apply to any observable.

I ask about physics because physics is what this philosophical article is about. It is NOT overly narrow for this situation; the article is explicitly about the philosophy of time, and misunderstanding what time is (i.e. thinking it's some sort of construct and ignoring physical evidence of its features) makes it impossible to talk about this with any gravitas (ba dum tsss).

Is space physical? Electromagnetism? Your rationale applies to many things that it would be innacurate to say aren't physical, not just time.

If you haven't studied special and/or general relativity with some rigor, then you might not be qualified to answer questions about it.

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Matt5327 t1_j0mw9vc wrote

The concern is more linguistics in this case. Yes, the article brings in physics but it’s not about physics, per se. Therein lies the challenge.

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[deleted] t1_j0masc2 wrote

The human experience of time is different in some sense though.

Our experience of the three space-like dimensions maps very readily to what we can observe. However, there is no immediately apparent reason why we should experience time as continuous "flow" in one direction only. We can see some properties of movement through time, such as an inexorable increase in entropy, but how this translates to our subjective experience of unidirectional time is, as far as I'm aware, unexplained.

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CaseyTS t1_j0me686 wrote

There is a more difficult conversation about entropy that might address the "flowing" of time or the experience of it as sequential. I'm not super qualified to talk about that particular issue though.

My basic understanding is that time and entropy together (with the initial conditions of the universe, hot with low entropy) create a physical universe that includes causality. Then, consciousness relies on causality because it's about recieving information, processing that info, and acting. Then, we can consider natural selection, and think about how our consciousness appeared in this world in the first place.

Sorry that's not rigorous. I don't have a full answer. You bring up some good points. Still, I think entropy is related to the answer about time flow, and I think that how we experience time is a result of both its physical properties and our brains' physical properties.

Edit: the entropy, time, and big bang stuff is a Cosmology topic, btw, for whoever's into this sort of thing

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