jeremy england: are we dissipating energy or entropy?
Posted: Wed Jul 15, 2015 2:32 pm
I am a non-physicist trying to make sense out of the different concepts of information and entropy in various fields.
Prelims: Jeremy England’s recent work on ‘dissipation driven adaptive organization’ has proposed that mechanisms for dissipating energy help small-scale physical systems self-organize and self-replicate — this sounds like a variation on (further elaboration of) the familiar concept of dissipative structures that goes back to Ilya Prigogine and the work on self-organizing systems done by Stuart Kauffman and many others (both biologists, so not cited by physicist England, as far as I can tell).
My question: The current discussion seems to be all about the energy such systems dissipate — I have seen almost no mention of entropy.
From some angles, the issue that living organisms have to deal with is not energy — on earth, that’s everywhere — but entropy. What keeps organisms alive, and non-living dissipative systems stable, is not their ability to dissipate energy — everything can do that — but their ability to dissipate entropy as a way to protect and reproduce their internal information or organization — they ‘dump’ or ‘pump’ entropy into the environment, rather than becoming disorganized by it.
The idea that entropy can be moved around is a little touchy, I think. Physicist Erwin Schrödinger famously wrote in his What Is Life? that life feeds off of negative entropy — now usually termed negentropy. He said in a footnote that, for physicists, he would have said ‘free energy’ but he did not back away from the idea of negative entropy.
It seems to me that England’s energy dissipating systems are actually entropy-dissipating systems, that the dissipation of energy is necessary but not the essential point — they are using the increased flows of dissipated energy to carry off the unwanted entropy, much as nuclear power plants use water to carry off heat — thus, though they are indeed dissipating energy, the more relevant point would seem to be that they are dissipating entropy. I have noticed before that, while everyone (except some creationists!) understands that the general tendency toward increase of entropy is reversed (or resisted?) in living systems, the tendency both in physics and biology is often to focus on the energy aspects of the process and to neglect the importance of the (neg)entropic aspects?
Thoughts? Thanks, Charlie.
Prelims: Jeremy England’s recent work on ‘dissipation driven adaptive organization’ has proposed that mechanisms for dissipating energy help small-scale physical systems self-organize and self-replicate — this sounds like a variation on (further elaboration of) the familiar concept of dissipative structures that goes back to Ilya Prigogine and the work on self-organizing systems done by Stuart Kauffman and many others (both biologists, so not cited by physicist England, as far as I can tell).
My question: The current discussion seems to be all about the energy such systems dissipate — I have seen almost no mention of entropy.
From some angles, the issue that living organisms have to deal with is not energy — on earth, that’s everywhere — but entropy. What keeps organisms alive, and non-living dissipative systems stable, is not their ability to dissipate energy — everything can do that — but their ability to dissipate entropy as a way to protect and reproduce their internal information or organization — they ‘dump’ or ‘pump’ entropy into the environment, rather than becoming disorganized by it.
The idea that entropy can be moved around is a little touchy, I think. Physicist Erwin Schrödinger famously wrote in his What Is Life? that life feeds off of negative entropy — now usually termed negentropy. He said in a footnote that, for physicists, he would have said ‘free energy’ but he did not back away from the idea of negative entropy.
It seems to me that England’s energy dissipating systems are actually entropy-dissipating systems, that the dissipation of energy is necessary but not the essential point — they are using the increased flows of dissipated energy to carry off the unwanted entropy, much as nuclear power plants use water to carry off heat — thus, though they are indeed dissipating energy, the more relevant point would seem to be that they are dissipating entropy. I have noticed before that, while everyone (except some creationists!) understands that the general tendency toward increase of entropy is reversed (or resisted?) in living systems, the tendency both in physics and biology is often to focus on the energy aspects of the process and to neglect the importance of the (neg)entropic aspects?
Thoughts? Thanks, Charlie.