Theories of Time

[lpetrich]

Philosophers have come up with several theories of time. Are only present events real? Are past events also real? Future events also real? Here's a list of theories:

1. A theory: Presentism: present
2. A theory: Growing block universe: present, past
3. B theory: Eternalism, block universe: present, past, future

Adding to the B theory is four-dimensionalism, which states that objects have extension in time as well as in space.


Presentism seems like common sense, but advocates of the other two theories would say that "common sense" involves using "existing" as a shorthand for "existing in the present". Adding to the confusion is that several languages have only one verb tense for both existing in general and existing in the present. English, however, has two present tenses, one for the first and one for the second:

• I read this site.
• I am reading this site.

Speakers of languages with only one present tense would either infer which sense from context or else would add qualifiers:

• I read this site every day.
• I am reading this site right now.

Then there is the question of the Universe of modern science. Newtonian mechanics follows naive common sense very closely, but relativity does not. Time is relative in it, just as space is. One might want to define some universal present relative to some point where one is now at, but if one started moving relative to one's earlier reference point, then that would-be universal present would become part-past and part-future. So relativity is thus most consistent with the B theory/ eternalism / the block universe.

I've seen an effort to rescue the A theory in relativity: the Lorentz Ether Theory. It posits some sort of special time coordinate where the only real parts of the Universe are those with the same value of that time coordinate as one's present. Thus, the real part of the Universe is a continually-advancing spacelike hypersurface in it.

But that seems very contrived, and there is no physical motivation for any specific choice of such a "universal present" hypersurface.


A criticism that I've seen of the B theory is that implies that the Universe is static, that all times exist together. But that's confusing viewing from outside with viewing from inside. We live in the inside of the Universe, not the outside.


Does that cover the issue, or is there more to be said?


Refs:
Time (Stanford Encyclopedia of Philosophy)
Time [Internet Encyclopedia of Philosophy]
 A-series and B-series,  B-theory of time,  Presentism,  Growing block universe,  Eternalism (philosophy of time),  Four-dimensionalism,  Lorentz ether theory

 

[Mageth]

There's "Time does not exist. (Only change)." See Ernst Mach, and Julian Barbour's work:

http://www.platonia.com/ideas.html

"Mach remarked “It is utterly beyond our power to measure the changes of things by time. Quite the contrary, time is an abstraction at which we arrive through the changes of things.” Thus, time as such does not exist but only change.... The quantum universe is likely to be static. Motion and the apparent passage of time may be nothing but very well founded illusions."

An essay by Barbour:

http://www.platonia.com/nature_of_time_essay.pdf

 

[Kharakov]

Duration of existence is real- some people see time as duration of existence (despite the eternal nature of now). While it is always now for every observer, it's pretty easy to infer duration via observations of periodic and other regular changes.

I tend to agree with 2A- a present that has roots in the past, growing towards a future from all points, with some caution because of the pain and suffering caused by a bit of youthful exuberance- which is now a more tempered love for existence, someone close, and family.

 

[Valjean]

Didn't science snatch the ball from philosophy in 1905 (Special relativity)?

 

[Kharakov]

Help, I'm stuck in a time cube.

 

[lpetrich]

Didn't science snatch the ball from philosophy in 1905 (Special relativity)?

I referred to that a bit in my OP.

Common sense and Newtonian mechanics agree that time is universal and independent of space. But that does not fit very well with Maxwellian electrodynamics, and experimental results seemed to side with Maxwell rather than with Newton. The solution that worked the best was devised by Henrik Antoon Lorentz. Moving relative to a special reference frame or "ether" altered space and time in a way that was consistent with Maxwell's equations. Albert Einstein considered this issue and he concluded that this ether was a totally superfluous hypothesis with impossible-to-measure motion.

The Lorentz Ether Theory of time is an attempt to make the A theory relativity-compatible. Only what's at the "ether present", as it may be called, is real, even if it is past or future from one's moving relative to the ether.

Not surprisingly, the B theory has much less trouble in relativity, because "present" is relative.

 

[lpetrich]

There's "Time does not exist. (Only change)."

However, that raises the question of how one recognizes change.

 

[Kharakov]

There's "Time does not exist. (Only change)."

However, that raises the question of how one recognizes change.

Not only that, but one infers duration from change, unless one descends into Last Tuesdayism.

 

[ontological_realist]

" Philosophers have come up with several theories of time. Are only present events real? Are past events also real? Future events also real?"

What is meant here by "real" ?

 

[fromderinside]

However, that raises the question of how one recognizes change.

Not only that, but one infers duration from change, unless one descends into Last Tuesdayism.

One recognizes change relative to that which is more stable, constant, than what is being measured.

 

[DBT]

A relative rate of change in the macro world as our measurement of duration, which we as the observer/experiencer define as being an instance of ''time?''

 

[Juma]

Since there is a maximum speed, time is "hardcoded" into space-time.
No change is necessary. The now of a resting reference frame always moves with speed c in time.

 

[steve_bnk]

A philosophical theory of time makes as much sense as a philosophical theory of the meter or kilogram. The second, meter, and kilogram are metrics we use to measure change. Time is no more special than the meter or kilogram. All three are required to objectively describe observed reality.

The philosophical question that is left is causality and ultimate origins of the universe. It is where religion, philosophy, and science converge.

So far all experiments show causality and observation can not be violated.

We observe all matter is in motion. We have no reference frame that we can say is universally at rest.

 

[Juma]

A philosophical theory of time makes as much sense as a philosophical theory of the meter or kilogram.

There is a philosophical theory of meter and kilogram. It is called theory of relativity. It has been successfully shown to explain and predict a lot of experimental data.

Trying to outdefine philosophy from its true role doesnt make it true.

Science = philosophy + empirical evidens

 

[steve_bnk]

A philosophical theory of time makes as much sense as a philosophical theory of the meter or kilogram.

There is a philosophical theory of meter and kilogram. It is called theory of relativity. It has been successfully shown to explain and predict a lot of experimental data.

Trying to outdefine philosophy from its true role doesnt make it true.

Science = philosophy + empirical evidens

Philosophy does not exist.

There is no 'philosophy' that does things. It is a broad historical category of human thought.

In Europe there was Doctor Of Medicine, Doctor Of Laws, and Doctor Of Philosophy that covered everything else.

Natural Philosophy became modern empirical mathematical science starting with Newton and his mechanics/calculus. Metaphysics alone became inadequate to keep up with physical experiments and discovery..

More properly both science and some areas of philosophy are systems metaphysical abstraction with science tied to unambiguous physical definitions, Systems International.

If you think philosophizing equates to science, then you are suffering from 'science envy'...

Science existed before any metaphysical abstractions. The original human tools, weapons, and agriculture. Science is an evolutionary process not defined by any philosophy or set of rules.

 

[Juma]

Science existed before any metaphysical abstractions. The original human tools, weapons, and agriculture. Science is an evolutionary process not defined by any philosophy or set of rules.

You confuse engineering with science.

You have some hangup with some philosophers and that distorts your perspective.

 

[Valjean]

No time. No change. No wavefunction collapse.
Time is, essentially, an illusion; an artifact of a focused, steadily "moving" consciousness.

 

[T.G.G. Moogly]

Since there is a maximum speed, time is "hardcoded" into space-time.
No change is necessary. The now of a resting reference frame always moves with speed c in time.

Or doesn't move at all.

My take on time has always been that if I can move at c I become infinitely massive and am everywhere all of the time. So by my reckoning time is a measure of distance, not movement/motion.

 

[steve_bnk]

Science existed before any metaphysical abstractions. The original human tools, weapons, and agriculture. Science is an evolutionary process not defined by any philosophy or set of rules.

You confuse engineering with science.

You have some hangup with some philosophers and that distorts your perspective.

No hangup, philosophy is simply irrelevant to modern science. The hangup is with those who consider themselves philosophers claiming that somehow science was dveloed by 'philosophy' without being able to quantify what that means.

Hardly. Science and engineering are the same instinctual processes. Popularized science like particle physics and cosmology is a very small part of all that science encompasses. Science and engineering build models. Unless you wish to assert that there is a different reasoning ad logical process to the two areas?

Science works regardless of how you philosophize it it is ultimately our brains and how they are wired.

Science ad engineering is are skills that are learned part by wrote learning and part by experience. Science ad engineering involve the process of abstract synthesis,and there are no rules on how to accomplish that, the brain neural net is trained by experience.

The terms philosophy and philosopher are amorphous ill defined terms. Philosophy was the pursuit of knowledge, and a philosopher was a seeker of knowledge.

 

[fromderinside]

Science existed before any metaphysical abstractions. The original human tools, weapons, and agriculture. Science is an evolutionary process not defined by any philosophy or set of rules.

You confuse engineering with science.

You have some hangup with some philosophers and that distorts your perspective.

Those who selected seeds, learned to extract metals and work them, built things, were all, in part, scientists. The only philosophy I see in such is the human imperative to exist and that isn't philosophy, but, has been found to be biology and evolution.

To suggest one doesn't change things through the methods above ignores change itself.