28 February 2010

Maxwell's demon: Hoyle's steady state

The second law of thermodynamics says that we can't win. The amount of useful energy available in the cosmos, and in any "closed system" within the cosmos, is lessening. Why? Well ... because useful energy is created by differences. For example, the water above a cliff has a different altitude than the water at the bottom of the cliff. Hence, the resulting waterfall can be employed to generate electricity. Over time, though, differences within any closed system are worn away (cliffs are worn down to level plains, entropy increases), which means that there are fewer and fewer opportunities for the generation of energy, i.e. the doing of work.

As an inevitable extension of this law, cosmologists speak of the "heat death" of the cosmos, in which what is left of the world is mostly nothingness, punctuated perhaps by whatever irreducible particles may remain, which simply drift further and further away from one another, without interaction, without heat, and of course without life.

If the world has that as an end, then presumably the world also had a beginning. The law of entropy naturally suggests the cosmogony of the Big Bang -- though as a matter of the history of science there was a period of contention as that implication worked itself out. Most notably, Fred Hoyle, Thomas Gold, and Hermann Bondi developed an elaborate steady-state theory in the 1940s, that would accomodate the expanding universe by having new matter pop into existence, so that the density of the universe remains constant over time. According to this theory as they and others developed it through the 1950s and 1960s, the new matter would be mostly hydrogen, and would be in such small amounts that it would not be directly detectable: roughly one hydrogen atom per cubic meter per billion years, with roughly five times as much dark matter.

Such a creation rate, however, could allow for the fact that all human-scale observations support the second law, while it allows for a subtle re-setting of the clock of time on the Big Scale involved, re-creating the differences, the disequilibria, that the unchecked operation of the 2d law of thermodynamics would destroy.

How did matter pop into existence, on that scale or any other? From a philosophical point of view, Hoyle etc. replied that this question is not more or less difficult than "how did the Big Bang happen"? One begs the universe all at once, or one begs it in pieces over the everlasting run of time. We are beggers in the matter of Being in either case. It is simply the old "why is there anything rather than nothing?"!

Yet this atoms-popping-into-existence stuff makes for an unattractive theory without more. That (perhaps even more than the background cosmic radiation, which has been called the echo of the Big Bang but could well have other explanations) has been the real drawback. If the popping is supposed to take place within the observable universe, it should be ... well ... observable.

Consider a thought experiment that goes back to one of the greatest physicists in history. James Clerk Maxwell spoke of a hyptothetical "demon" who could defeat the 2d law:

"If we conceive of a being whose faculties are so sharpened that he can follow every molecule in its course, such a being, whose attributes are as essentially finite as our own, would be able to do what is impossible to us. For we have seen that molecules in a vessel full of air at uniform temperature are moving with velocities by no means uniform, though the mean velocity of any great number of them, arbitrarily selected, is almost exactly uniform. Now let us suppose that such a vessel is divided into two portions, A and B, by a division in which there is a small hole, and that a being, who can see the individual molecules, opens and closes this hole, so as to allow only the swifter molecules to pass from A to B, and only the slower molecules to pass from B to A. He will thus, without expenditure of work, raise the temperature of B and lower that of A, in contradiction to the second law of thermodynamics...."

Notice that Maxwell is not bringing God into the picture here -- he is thinking as a secular scientist, and is specifying that the demon is as "essentially finite" as we are. But the demon works at a different level, a micro-level.

Notice also that while Hoyle et al sought to limit the Second Law to the human scale by escaping toward a much Bigger Picture, where humanly undetectable violations thereof can become important ... Maxwell follows the opposite strategy. He seeks to limit the Second Law to the human scale by escaping toward a much Smaller Picture, where an intelligent being can work molecule by molecule.

And now we bring in nanotechology, the development of a molecule-by-molecule, indeed atom-by-atom, variety of engineering accoring to which humans may yet create robots that can in term act as does Maxwell's hypothetical demon.

Ah, am I suggesting, by making this connection, that humans have a cosmic role to play by inventing Maxwellian demons that will enable the cosmos to avert heat death? No ... not exactly. That would have an unnecessarily arrogant sound to it. There is no reason to believe that life exists only on this planet, or that the intelligent beings here have a unique role.

Perhaps through the everlastingness of time, intelligent creatures have developed on myriad planets, and that in many of these cases they reach a point at which they develop a nanotechnology capable of beating the 2d law in their localities. And perhaps, the collective effect of all these independent nanotechnological/civilized planets is to keep re-setting the clock. Perhaps intelligent life on sporadically located planets has the same effect that Hoyle sought to model through this random popping into existence of hydrogen atoms he hypothesized.

The alliance of Hoyle and Maxwell moves in both directions at the same time, for the tiniest of scales may give us a crucial clue to what is happening on the largest.


Sylvia Jane W. said...

I’ve been following your Pragmatism Refreshed blog for quite a while and enjoy and profit by your insights on all topics philosophical as well as others. Among the most vexing philosophical problems I wrestle unsuccessfully with is Descarte’s Evil Demon problem and its contemporary, made famous by the Matrix “brain-in-a-vat” incarnation. I know philosophy means a lot to you, as it does to me. Your wonderful book, These Last Four Centuries, approaches philosophy exactly as I do—as a tool to understand how the world works, how to best live in it, and what it all means in the first place. How can we be sure that our experiences are real and not a dream or the result of a Matrix-like nutrient induced and computer-like simulated mental state? Camus believed that “the absurd” was the only true philosophical problem but I think the question of whether we can ever know—really know—reality is much more fundamental, for unless we can be truly apprehend reality, it seems to me that what we think about anything else doesn’t much matter. Everything is make-believe until and unless we can come to terms with Descartes and the Matrix. Human beings take life seriously and those who take it most seriously don’t feel comfortable thinking and acting without being reasonably sure that any castles they might have begun building in the air ultimately have a foundation in reality. We want to be sure: to know that what we believe and do are consistent with reality—not just for its inherent survival value but also because it’s a matter of integrity and pride in the truest sense of the Greek concept of arĂȘte—excellence.

Perhaps I am just being some combination of thick and oblivious to a solution or at least a reconciliation that would provide some firm ground to stand on and go more confidently forward with the rest of philosophy’s and life’s agenda. I’m past Philosophy 101 (I like to think) and nothing I’ve read or learned along the way has proven enlightening. I know you are a big fan of William James and Jacques Barzun. Is there anything they’ve written about this problem that would help put it to rest?

So I wonder if you would mind providing your take on all of this? Perhaps you would consider it as a worthy topic for your blog in which case others might chime in with their thoughts. Please feel free to reproduce any and all of this note should you decide to discuss it in your blog. Thanks so much!

Christopher said...


Thank you for your kind words about These Last Four Centuries.

Something William James said that is pertinent to your concerns is this: "If this life be not a real fight, in which something is eternally gained for the universe by success, it is no better than a game of private theatricals from which one may withdraw at will. But it feels like a real fight.”

That's from "Is Life Worth Living?," a speech he gave to tyhe Harvard YMCA in 1895.

Start with the question: do you make decisions, or do you only seem to yourself to make decisions? Hold up one of your arms right now. Or ... don't.

Which did you do? and which arm was it?

There are different ways in which one might contend that we don't make decisions. James was more worried about a rigorous determinism than he was about the Cartesian evil demon. But either way ... the result of the skeptical argument would be that I don't really make decisions. The universe of which I am a puppet makes them for me (if I'm a determinist) or I only dream that I make them (if I'm in the clutches of the evil demon).

If we don't make decisions, then this life is not as James put it "a real fight."

So ... is it? What we can tell for sure is that it "feels like a real fight," so I'm justified in acting on the presumption that it IS a real fight, that I make decisions that will matter, at least provisionally, am I not?

Knowledge is warranted belief -- it is the body of belief that we build up because, while living in this world, we've developed good reasons for believing it. What we know, then, is what works -- and it is, necessarily, what has worked for us, each of us individually, as a first approximation. For my other blog, on the struggles for control in the corporate suites, see www.proxypartisans.blogspot.com.