Addy Pross
speaker
120 appearances
1 recordings
1 series
first heard Oct 2024
last heard Oct 2024
Addy Pross’s voice in public audio — every appearance, attributed to the second.
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Yeah, well, that's where the difficulties start. There are literally hundreds of definitions of life. And the fact that there are so many definitions means that probably none of them are very good. Otherwise, you wouldn't need hundreds of definitions. And the biological ones tend to be focused on biological aspects, nucleic acids, proteins, replication, evolution.
And the more physical ones tend to look at more physical aspects, self-organization, information, stability, instability, etc. But that hasn't somehow, that hasn't been enough. And I think there have been developments in the last several years in systems chemistry, which I think can make a definition that enables you to have a recipe how to make life in principle.
An outline would be useful, and that's which I will mention in a moment. It's based on the idea that we've just learned, as I say, that there's a new – There's a new state of matter that's been uncovered in chemistry in the last 10, 15 years, a remarkable thought. Chemistry is a very established science now, and yet we've discovered that beyond the familiar thermodynamic states of matter,
There are kinetic states of matter, and we'll need to talk a little bit about that and what that means. And life, if I have to define life now, I would say it's a replicating chemical system in this dynamic kinetic state, this new state of matter that's been recently discovered.
Well, that's exactly the nature of this new state of matter that I'm going to describe a little bit. We're very familiar with the thermodynamic states that basically say that matter wants to be in a low-energy state. Right. But the strange thing is that stability has, which we use frequently in science, but not just in science, has two meanings which are actually quite different.
One is in science we tend to think of stability as low energy, but stability in an everyday sense means energy. persistent, unchanging over time. And these two terms don't have to be overlapping, and they're not always overlapping. So when we talk about thermodynamic stability, they're overlapping. Why? Because when something is low in energy at its lowest energy state, it is also persistent.
It sticks around effectively forever. But it turns out you can have stuff that is unstable in energy terms but stable in time terms. And time stability is, in a sense, more fundamental than energy stability because it encompasses both kinetically – stable systems and energetically stable systems.
So this is the essence of what I'm going to talk about, that you can have something that is unstable energetically, but it's stable in the time sense. It persists. And just to make that clear, life has been around for close to four billion years, bacteria for most of that time. That is pretty persistent, pretty stable in the time sense.
Well, that's the bottom line. The answer is yes. And some forms of that are actually very familiar. And the metaphor I like to use, a physical metaphor for this kinetic stability, is the simple phenomenon of a water fountain. There's this wonderful fountain in Geneva. It goes up, you know, whatever, 150 meters or so. And it is stable in a time sense.
Whenever you go to Geneva, there it is doing what fountains do. But it's clearly unstable in an energetic sense. The water in that fountain is suspended in midair. So what's going on here? You can have something stable in a time sense because it is being created in a dynamic way so that the fountain as an entity is stable.
persistent, stable in this time sense, but the water drops in the fountain are continually turning over. Now, that's a physical, a very simple physical phenomenon. description of kinetic stability, but some 15 years ago, chemists discovered chemical fountains.
In other words, materials that are unstable in an energetic sense, but persistent and stable in a time sense because they're turning over consistently, continually through Yeah, the stuff coming in all the time, the energy coming in all the time in particular.
Absolutely.
Yeah. Well, as you say, physicists have been familiar with this idea actually for a while. Prigogine, in fact, got a Nobel Prize for its contributions to non-equilibrium thermodynamics. And the familiar examples then, there are, I mean, I spoke about fountains, but hurricanes, whirlpools are such structures that are stable,
persistent in the time sense, as long as you have energy provided to them. But what was not familiar is that you can have chemical systems that behave like that, and life is the ultimate example of dynamic, kinetically stable material, which is continually undergoing change, and just as I said, the water drops in the fountain are turning over all the time.
In a few months' time, you will be a totally different person. Most of the stuff that is you won't be you anymore. It's still you, but the stuff has been turned over, and it's new stuff all the time.
analog of that is there is there some particular kind of chemistry that we need to make the dynamic kinetic stability work not really just a source of energy generally typically it will be chemical energy uh the classic example um was when this work was uh this area was uh discovered um was with a very simple reaction, one of the most basic reactions in chemistry, esterification.
Now, if you take a carboxylic acid and you methylate it, which you can consider a source of material but also a source of energy, you end up with an ester. Now, that is a downhill reaction, because you started off high in energy, and you go downhill, and you end up with your ester, nice crystals. And that's a very familiar reaction that we've known for, I don't know, well over 100 years.
But what two young Dutch chemists discovered, which was quite remarkable, that if you do this reaction in a dynamic way, namely, turn the acid into the ester, and then continually degrade the ester back to acid and then make more ester all the time in this dynamic way, you end up with a new form of matter. You end up with a hydrogel.
Not crystals, a hydrogel, which has unusual properties because it's composed of both the ester and the acid in a dynamic process. Now, the other thing that's very interesting here and very relevant to life is for that one thermodynamic process with one thermodynamic state, you have thousands,
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