Does Dr. Brian Cox need to be taken out to the logic woodshed?

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This topic contains 15 replies, has 5 voices, and was last updated by  PopeBeanie 2 months, 3 weeks ago.

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  • #25252

    Unseen
    Participant

    Now, as a science appreciator whose background is in philosophy and logic and not physics and cosmology, I usually love to watch Dr. Cox’s dumbed-down explanations of science for commoners like you and me.

    I’ve heard many another scientist say that the directionality of time is a bit of a mystery since the equations as equations have no direction (in the simplest terms, if a=b then b=a), yet time clearly presents itself as 100% directional. An exploding balloon will not come back together all filled up with pressurized air. If you burn The Mona Lisa, it’s gone. Forever.

    Well, Dr. Cox gives his explanation of the directionality of time in the following viddy. My argument follows it.

    We all know how to counter the argument that you need God to explain the creation of the universe, which is “Okay, but that, if true, only moves the locus of the mystery to who or what created God.” If the answer is that God just is, then the explanation is simply a mystery on a different level.

    Dr. Cox’s explanation that entropy explains the directionality of time similarly just moves the mystery to a different level: Why is entropy directional? or why is there entropy? Or any number of other questions.

    Mystery still not solved. Or is it?

    • This topic was modified 2 months, 4 weeks ago by  Unseen.
    #25255

    Simon Paynton
    Participant

    Random entropy can’t be reversed, or is vanishingly unlikely to spontaneously reverse.  So it can happen forwards in time, but not backwards.

    We can go from “higher entropy” to “lower entropy” randomly in a reverse direction, because going forwards, things go from lower entropy to higher entropy, randomly.  But we can’t go from lower to higher entropy, randomly, in a reverse time direction.

    #25256

    _Robert_
    Participant

    Yeah, still lots of an onion of unknown size left to peel as we head towards oblivion. These are the kinds of questions that prove that we are universally agnostic about the cosmos. It is so mysterious that I will never rule out an intelligent prime mover and yet I am an atheist.

    #25257

    Unseen
    Participant

    Random entropy can’t be reversed, or is vanishingly unlikely to spontaneously reverse. So it can happen forwards in time, but not backwards. We can go from “higher entropy” to “lower entropy” randomly in a reverse direction, because going forwards, things go from lower entropy to higher entropy, randomly. But we can’t go from lower to higher entropy, randomly, in a reverse time direction.

    I often rephrase Newton Law #2 as “Things tend to come apart unless some force is holding them together.” But Cox still hasn’t answered why entropy seems to be directional.

    #25260

    Simon Paynton
    Participant

    Because there are many ways to undo something, but only one way to put it together.

    #25262

    Unseen
    Participant

    Because there are many ways to undo something, but only one way to put it together.

    Wrong. There may be only one original state, but many ways to get back there (in most cases). If I drop a widget and it breaks into pieces 1, 2, 3, 4, and 5, the reconstruction can start by pieces 1 and 2 coming together, or 1 and 3, or 3 and 5, and so on. You see what I mean.

    #25266

    Simon Paynton
    Participant

    There may be only one original state, but many ways to get back there (in most cases).

    This is the whole point: something has one original state, and many states of entropy.  So, if each state is arrived at by random chance, then statistically, it’s very unlikely to end up in the original state again.

    #25267

    _Robert_
    Participant

    There may be only one original state, but many ways to get back there (in most cases).

    This is the whole point: something has one original state, and many states of entropy. So, if each state is arrived at by random chance, then statistically, it’s very unlikely to end up in the original state again.

    The energy expended in reconstruction raises the overall entropy

    #25273

    Simon Paynton
    Participant

    There you go: trying to reverse entropy only causes more entropy.

    #25274

    Unseen
    Participant

    This is the whole point: something has one original state, and many states of entropy.  So, if each state is arrived at by random chance, then statistically, it’s very unlikely to end up in the original state again.

    But only if one assumes “normal” time, which seems to be directional quite apart from entropy. The sun comes up, I wake up, bathe, brush my teeth, shave, get dressed, eat, go to work (blah blah) come home, eat, get ready for bed, sleep.

    THAT, you’re trying to tell me, is due to entropy?

    • This reply was modified 2 months, 3 weeks ago by  Unseen.
    #25276

    Simon Paynton
    Participant

    I think the answer of the question of why one thing happens after another is about the nature of time itself – what is time?

    #25277

    Most people think of Entropy within a system as change from a state of order (low entropy) to a state of disorder (high entropy), like the sandcastle in the video eventually eroding away. But there is a better way to look at it. Instead of thinking that a system (randomly) moves towards a state of high entropy or disorder, consider instead the probability that it will move in that direction.

    When the wind blows on the sandcastle molecules from the air interact with the molecules (or atoms) of the sand grains. There is a very high probability that this will rearrange their structure. It is similar to scrambling an egg. The molecules are rearranged (the enzymes and proteins are changed due to heat energy and this changes the structure of their Mass (conservation laws). The “state” or “configuration” of the egg has changed completely. It now has a new atomic structure so it is basically a new system. The probability that this would happen once heat (or wind on the sand grains) is applied to it is very high.

    It is very (very, very) improbable that those initial states (not in a closed system) will not change. The state of the raw egg becomes so disordered that it no longer exists in its original configuration. The scrambled egg then has a low entropy until I eat it which changes its structure again and it quickly becomes disordered. The sand grains never return to their initial position so we never get the “same” sandcastle again.

    However there is nothing in the laws of physics to say that the wind will not blow all the sand grains back into their initial structure but this is highly improbable as to be statistically a non-event. It is so improbable that we dismiss it as being virtually impossible, like the existence of a god.

    If someone kicked my sandcastle then it would be very “disordered”. There would be so many different ways of rebuilding it that it would be extremely improbable that we could ever do so with the sand grains in the same arrangement. Unless we could go back in time – by reversing the expansion of the Universe?? It is its expansion that creates Time.

    #25292

    PopeBeanie
    Moderator

    We’re speaking of probabilities; generalizations about how universal laws can be understood as determinants in the forward flow of time. My life view (currently or increasingly) is to avoid the “why” questions and focus on the “how” explanations. The fact that we can even consider time going backwards is a mystery to me, deserving of a medal or award only because it requires human creativity to fathom its possibility; it’s fiction, like God. Time moves “forward”; it always has, and the evidence is overwhelming and undeniable. Considering otherwise is fantasy. Forget about “why”. (Sorry, that does remove a lot of fiction and entertainment!)

    All of the significant organization of matter that we take note of requires energy. Life itself had to have begun with basic exothermic chemical processes, i.e. chemical energy was “used up”, heat was given off (even inefficiently, as waste) in the more inevitable process of atoms bonding together into molecules; and then molecules organized when available energy (e.g. more chemical or solar energy) enabled the organization to occur. And then given billions of years and ample energy input, self-replication begat more self-replication, not because of any creative force, but because of plain old everyday, local nuclear and chemical forces in combination with those ambient energy sources.

    Another generalized way to understand how matter organizes itself is to see how energy gets “locked up” in the organization of matter. Biologically, sugar and cellulose are my favorite examples of that. Both are only possible with energy from the sun, and both are used universally on the planet as fuel sources for increasingly complex organization, e.g. animals evolved to move and predate, possible only with the existence of the simplest plant life forms that had solar/chemical energy locked up that could then become available as “food”. (The energy in cellulose is locked up in the form of structural strength, e.g. tall standing trees for capturing more solar energy, releasable later only slowly after plant death and decay, or released quickly in the less usual fire.)

    All of the above is pretty complex and requires decades of learning to understand. It’s no surprise (to me) that humans fall into simplistic explanations that involve whys rather than hows. Whys are the currency of intelligent agency and intentions, attempting at times to explain the hows, but the whys are more useful for self-justification and enforcement of desired behaviors than they are for explaining scientific laws and the behavior of matter.

    #25293

    Simon Paynton
    Participant

    Forget about “why”.

    We want to know “how” time flows forward along, presumably, the t axis (or local axes) of spacetime.

    We know why, or how, it can’t flow backwards – entropy is not allowed to decrease.  How that is proven is an interesting question.

    #25294

    _Robert_
    Participant

    don’t ever ever ask Richard Feynman WHY Magnets attract

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