"Closed time-like curves"

Gregory

There is a book I saw tonight on Google called Godel meets Einstein. There is another book I've been wanting to get (called The Physicist and the Philosopher) ever since I've seen the author Canalas's you\tube talk on it. Canalas's book is about the Bergson encounter with Einstein wherein the physicist said philosopher's concept of time was dead. I just wanted this to be a quick post on time. It seems to me that our senses and scientific instruments cannot detect time, therefore defining what it exactly is is completely and solely within the realm of philosophy.

So that is my first point. My second one is how I noticed tonight that Godel's ideas of time dovetail with a new idea I have about the big bang. If time can be the reverse of itself, cannot we say that the universe started by "reverse annihilation" ?: that is, just as a pair can, within logic at least, destroy each other, could n't the Big Bang be seen as an annihilation within which time runs backwards? I've actually wondered for awhile now if time really runs backwards. If time can run more than one direction it might solve causality problems related to the question of "origin, and now suddenly I am reminded of ideas from Samuel Alexander.
Thanks

antor

The existence of reverse phenomena may be important sometimes. But you're basically saying creation can be seen as reverse destruction which would kind of lead to reverse time? As a physicist myself, I simply reply "so?". The laws of physics are indifferent to time-reversal so what kind of language we apply to forward or backward in this case is only our purely linguistic decision and it has no impact on the reality of the situation. Look up CPT violation and related topics on wikipedia if youre interested.

Gregory

↪antor

The PBS digital series on spacetime is now saying, along with other video makers, that gravity is caused by time. If time runs in the opposite direction we think it does, it creates a circular situation wherein time (and thus gravity) is sufficient to understand the start of the universe

Gregory

↪antor

Are you familiar with the arguments of Aristotle, Aquinas, and Duns Scotus on how motion, causality, and change in the universe cannot to fully explained in physical terms? Answering their arguments is what a theory of everything is really about

Gregory

"Closed time-like curves" is Godel's phrase. This question is a physics AND philosophy question. You can't deal with the beginning of the universe in terms of only one or the other. A year ago I thought momentum from gravity was the essential movers, so that the universe was at the state of second "one", and descended from it's state into the motion of inflation. All time (seen as a spatial entity) was from the universe being at it's "top" state and descending, gaining energy from momentum. I've adjusted my position because physicists here in America are saying that time is most fundamental.

reverse destruction which would kind of lead to reverse time — antor

Reverse destruction was just an expression and the reverse of time is the cause, not something caused by destruction or whatever

The laws of physics are indifferent to time-reversal so what kind of language we apply to forward or backward in this case is only our purely linguistic decision and it has no impact on the reality of the situation. — antor

Sure, if you want to see it just in terms of math, instead of as it really happened.

javi2541997

The laws of physics are indifferent to time-reversal so what kind of language we apply to forward or backward in this case is only our purely linguistic decision and it has no impact on the reality of the situation. — antor

Thank you for sharing your thoughts from a professional point of view as physicist. But it is interesting how dependens the notion of "time" in our reality when we introduce it in the vocabulary.
I guess it is impossible to fraction the time, i.e "30 minutes less to end the class" or "how the life flies by" etc...
Probably it isn't impact in terms of reality but it makes a huge impact in our days and living. We fraction the time just to make a chronological order and then make the life "easier" this is another example of how the humankind can be so abstract sometimes. Why the year is ordered by 12 months? Why are we exactly in "2021"? Etc...
Speak about time not only in science but in philosophy is so interesting from my point of view and I guess it is not dead as Einstein or Bergson proposed.

Paul S

It seems to me that our senses and scientific instruments cannot detect time, therefore defining what it exactly is is completely and solely within the realm of philosophy. — Gregory

Energy is spacetime. Spacetime is energy

Our concept of time is an abstraction.
There is no spacetime in the universe as a whole. It exists only where there is sufficient energy.

We are heavy in that we are made of matter, as is our world. Light is invariant. Almost beyond our ability to reason about, it travels at an invariant speed c. i.e. it has no mass (no potential and kinetic energy), no spacetime.
In the beginning there was light. Scientists have now successfully created matter (and antimatter) from high powered lasers.

In doing so they contributed to creating or warping spacetime with photons.
You could argue they created some quanta of time itself, since time is a human abstraction entirely dependent purely on energy.

Gregory

↪Paul S

In a very real sense we can say time doesnt exist, yes. Descartes and Leibniz said as much. But although time is similar to matter and needs matter, I don't think it is identical to matter. There is something there that is mysterious and which's nature is shown in relativity. Anti-matter has reverse time and i don't think this means just that it acts with the opposite motions of regular matter

Paul S

There is something there that is mysterious and which's nature is shown in relativity. — Gregory

I would argue that the mysteriousness is sourced in a lack of time though.
Light travels at invariant speed because it does not experience time as such.

Relativity only really applies to time as long as there is mass though.
If there is nothing relative to something else, there is no relativity.
If there is no mass around, there are no spacetime effects to perceive.

Banno

It seems to me that our senses and scientific instruments cannot detect time, therefore defining what it exactly is is completely and solely within the realm of philosophy. — Gregory

"It seems to me..." is not an argument.

Curiously, the time of each of your posts is shown directly under them.

Further, I'm writing this after you wrote your post.

So it seems that both we and the sever on which this thread is stored can detect time.

And we can conclude that he evidence is contrary to your assertion.

Gregory

↪Banno

Nobody denies succession of events. How succession of motions, causes, and change relates to the concept of "time", what time looks like, is a philosophy question. This is especially important since absolute time does not play a role in relativity. Scientists cannot help having philosophical ideas because you can't do science without it. But they don't always realize the many different ways their conclusions can be seen by philosophy. What is a massless particle? Can something come from absolutely nothing? How does Bell's theorem relate to compatabilism? Can a particle be at two places at once or is it really two particles? There are innumerable such questions and they relate to philosophy as much as to science

Banno

↪Gregory

You simply avoided the point: our senses and scientific instruments can detect time.

Gregory

↪Banno

They detect change, but saying change IS time is a philosophical theory

Gregory

The same applies to waves being called "processes". Ontology can ask "processes of what?" Can a process be fundamental? That's philosophy

Banno

They detect change, but saying change IS time is a philosophical theory — Gregory

I didn't say change is time. I said that you are wrong to claim our senses and scientific instruments can detect time.

Gregory

↪Banno

That depends on your philosophical understanding of time. What some scientists call time we can detect. What some philosophers call time time you can't detect. And positions inbetween these two is an area where philosophers and scientists should communicate on what they mean by time

Banno

As for Bergson and Einstein, a good analogy can be made by translating their difference into spacial positions instead of temporal positions.

Bergson was claiming that the only directions were left and right. Einstein, tha the only directions were north and south. Neither was right.

Banno

That depends on your philosophical understanding of time. — Gregory

Indeed; if you wilfully misunderstand the notion of time, you can convince yourself that there is a mystery where there isn't.

Our senses and scientific instruments can detect time.

Gregory

↪Banno

Measuring something is not detection. That's the confusion here. How to conceptualize these things can not be done fully in terms of measurement

Gregory

https://en.wikipedia.org/wiki/Philosophy_of_science

This is a real field of study

Banno

Measuring something is not detection. — Gregory

Hmm. So you are saying that we can measure time but not detect it.

With a straight face?

Gregory

↪Banno

I don't know why you dislike philosophy in how it applies to science but science can't do without philosophy whether you like it or dislike it

jgill

. . . but science can't do without philosophy whether you like it or dislike it — Gregory

Progress in science requires lots of speculation by scientists, and some of this could be called philosophy. But to stipulate that philosophers untrained in science can trigger scientific revolutions is a stretch. :roll:

Gregory

↪jgill

Their ideas bring paradigm shifts which allow scientist to frame theoretical matters in new ways. Philosophers don't do the measurements but measurements can never stand alone without conceptualization of them and those concepts have much to do with what is discussed in philosophy.

jgill

Their ideas bring paradigm shifts which allow scientist to frame theoretical matters in new ways. Philosophers don't do the measurements but measurements can never stand alone without conceptualization of them and those concepts have much to do with what is discussed in philosophy — Gregory

You may have a point, but I am unconvinced. You would have to demonstrate this philosophical prowess in examples in the modern world, not olden times.

Gregory

↪jgill

Take the example of whether you would go back in time of you went faster than the speed of light. Measurements say it can't be done but speculation on it is done by scientist and this might be fruitful for other aspects of science. And since it's not based on measurement it is philosophical science at that point.

Gregory

Penrose's conformal cyclic cosmology says, according to his interviews, that the universe will expand until "it no longer knows what size it is". You have to think philosophically to unpack what that means

Banno

I don't know why you dislike philosophy in how it applies to science.. — Gregory

I don't.

If what you say is to have any impact at all it ought at the least be factually correct. Our senses and scientific instruments can detect time. Denying this will not win agreement amongst philosophers, nor scientists.

Gregory

↪Banno

You can't tell what time is through measurement. You can't say if it's matter or not matter. You can't say anything about it from measurement.

Gregory

How can physicists attempt to explain the quantum eraser experiment if they aren't to use any philosophy?

Banno

You can't tell what time is through measurement. — Gregory

Time is what clocks measure.

Can't see this going anywhere.

You may have a point, but I am unconvinced. — jgill

The point being that philosophers can help scientists with conceptual orientation?

"Closed time-like curves"

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