Science's Big Query: What Can We Know, and What Can't We?

The Wall Street Journal ^ | Friday, May 30, 2003 | SHARON BEGLEY

[Alamo-Girl]

Thank you for sharing your views!

My personal experience does not comport with your view that

Can't be done [trying to know God by subscribing to only one religion] yet few would face up to that, and would even try to dispute it as if it should never be questioned.

[Alamo-Girl]

Tragic indeed. Thank you so much for your post! Hugs!

[edsheppa]

My point is that most (all?) attempts to define time eventual become circular.

I wouldn't consider geometrical definitions circular - time is the spacetime axis with the -1 metric coefficient. That certainly doesn't get at the feeling of it though.

The other noncircular attempts I know of revolve around the second law - time is the spacetime direction of increasing entropy. That get's closer to the feel of it. Basically, I think what that means is when we have the "real" laws, they will exhibit a direction to the correlation of events in the time axis but not the space axes.

[AndrewC]

The other noncircular attempts I know of revolve around the second law - time is the spacetime direction of increasing entropy.

I get the feeling that that approach will butt heads with Einstein.

[RadioAstronomer]

Thanks for the ping! I read a SiFi short story that went along those lines. As pot makers were inscribing the lines on the pots, the lines would vary slightly (similar to a phonograph record) due to surrounding sounds. In this story using special "equipment" you could hear the conversations and local sounds that were present during the creation of the pots.

What a cool dream you had. :-)

[boris]

"I wouldn't consider geometrical definitions circular - time is the spacetime axis with the -1 metric coefficient. That certainly doesn't get at the feeling of it though."

It sure doesn't.

"The other noncircular attempts I know of revolve around the second law - time is the spacetime direction of increasing entropy. That get's closer to the feel of it. Basically, I think what that means is when we have the "real" laws, they will exhibit a direction to the correlation of events in the time axis but not the space axes."

Arguments based on entropy never grabbed me. I saw (or see) them as an attempt to explain away a mystery. There is still a big bag of "why"s associated with such responses; they remind me of 'just-so stories'.

Maybe it is because humans lack a direct sense of entropy. We have senses for pressure and temperature. Entropy? What about fugacity? OMG.

Anyway I'd like a nice simple answer to the question of 'what is time?' but I fear I must wait to ask the Almighty the question, and why should He answer?

--Boris

[boris]

"Er, I was eavesdropping on your ”what is time?” discussion with Consort"

How dare you?...

Anyway, I'm aware of the Kaluza-Klein 'breakthrough' and somewhat familiar with brane theory, et al.

But not mathematically sophisticated that these theories 'explain' time to a simple engineer.

My readings on Time have taken me in many different directions (but not dimensions). Recently I've been reading extensively on Buddhism (no, a 51-year-old Jew is not going to convert to Buddhism). As I mentioned I've read Barbour and others extensively but they have not helped.

In a way it is presumptious to claim that human can in principle understand time, or that in principle we can claim to have 'complete' understanding of it. As I said, I suspect we are simply not the kind of creatures which can contain such understanding, all posturing to the contrary not withstanding.

Many of the books I've read on Time now seem like so much bafflegab; only Barbour and a few others seem to stick in my mind, to be turned over and over like a child examining a shell on the beach.

I am deeply confused and humbled, but it keeps me out of trouble.

--Boris

[AndrewC]

What about fugacity?

Chemist?

[Mr. Mojo]

BTTT, and bookmarked.

[balrog666]

Bump.

[Alamo-Girl]

Thank you so much for your reply and for sharing your quest for a digestible definition of time!

In a way it is presumptious to claim that human can in principle understand time, or that in principle we can claim to have 'complete' understanding of it. As I said, I suspect we are simply not the kind of creatures which can contain such understanding, all posturing to the contrary not withstanding.

Indeed, I find it rather revealing that we biologically have a three spatial dimension visual perception and struggle (and often fail) to rationalize a fourth dimension for time. It’s no wonder we have such difficulty with higher dimensions.

And that raises a deep spiritual question IMHO, i.e. why this particular choice of coordinates for biological visual perception?

For Lurkers interested in “visualizing” higher dimensions: The curse of dimensionality (pdf)

Also, Sandia National Laboratory is trying to help with that problem.

In post 106, you said to edheppa:

Anyway I'd like a nice simple answer to the question of 'what is time?' but I fear I must wait to ask the Almighty the question, and why should He answer?

I believe you will have the opportunity to ask and along with it, the unbridled perception to receive the answer!

[tictoc]

As it happens, the renowned scholar Frank J at http://www.imao.us/ addressed this issue the other day.

Here is his response to a reader question:

Q:
Robert J. from Gusev Crater, Mars asks:
Is the "Planck time" in any way like "Miller time"?

A:
As we all know, a Planck time is the time it takes a photon going at the speed of light to travel a Planck length. Just to remind you, a Planck length is the scale at which classical ideas about gravity and space-time cease to be valid. This is equal to 1.6x10^-35 meters. It takes a photon 10^-43 seconds to travel this length, and thus 10^-43 is the smallest unit of time that has any actual meaning in physics as we understand it today.

In the end, Planck time is a measurement of time, while the lesser-known Miller time expresses a condition of matter and is not an actual measurement. Miller time is reached with enough proton, electrons, and neutrons come together to form something referred to by physicists as a "fat party animal" which then proceeds to drink beer and dance around. This condition lasts for many times that of Planck time, and has undesirable aftereffects the morning after.

[Fiddlstix]

Read Later

[Mind-numbed Robot]

Thanks for the post. I know science well enough, and have been experimenting long enough, to know that after Miller time sleep takes place in Planck time.

[Way2Serious]

"LOL! Do I need to make my verse better or worse to threaten them?"

I guess it depends if you're a Vogon. Let's face it, it was no "Ode to a Small Lump of Green Putty I found Under My Arm."

I'm no judge of poetry by any means. One sci fi writer, Heinlein I think, wrote that reading one's poetry in public is just rude. In the end, all internet posting is about vanity anyway.

[Hank Kerchief]

Thanks for the ping!

I've been away. I have only two comments.

First: The application of the Heisenberg's uncertainty principle to the question of what can or cannot be known is absurd. As if the "position" and "momentum," if any actual particle could actually be identified, and either its position or momentum measured? The entirety of the uncertaintly principle is not an indication of what cannot be known, but an observation about the statistical nature of what can be known, and a failure of the statistical method to resolve certain aspects of sub-atomic behavior. (The fact that another method might produce different results seems beyond the imagination of the current crop of so-called scientists.)

Second: What cannot be known does not matter. There can be no importance or significance in what cannot be known. Only what can be known matters. If something cannot be known at all, in any way whatsoever, it is exactly the same as being non-existent. In fact, it is non-existent. It is a fiction.

By the way, there are not multiple universes, or existences, or realities, either, anymore than there are multiple personalities. Belief in either are similar pathologies.

Hank

[Alamo-Girl]

Thank you for the heads up and for letting us know your views.

[boris]

"Second: What cannot be known does not matter. There can be no importance or significance in what cannot be known."

Come now.

We can never KNOW with certainty precisely how the Universe began. Yet it is an immensely significant and important question.

Stuff that happens outside the light cone cannot affect us...but then there's the EPR paradox, sitting there grinning at us.

There are lots of 'unknowable' questions which would be seen as clearly significant--even world-shaking--if they could be known.

You cannot read my mind; I cannot read yours. Thus neither of us can know the thoughts of the other. I may be preparing to murder you; certainly this is 'unknowable' to you yet of supreme importance to you.

Occam's Razor is a fine tool but inappropriate for felling oak trees.

I could go on.

--Boris

[HiTech RedNeck]

I bet that there is so much chaos involved in how the drips hardened, and the effects of the sound vibrations on the process so minute, that to glean any information about individual sound vibrations from it would be impossible. Even if one could somehow analyze the position of enough of the molecules of the stalagmites and stalactites. Just like we wouldn't expect to be able to play back a phonograph recording done not in wax but in vaseline.

[Aquinasfan]

By the way, there are not multiple universes, or existences, or realities, either, anymore than there are multiple personalities.

How do you know that?