I wanted to put this question in the biology stack exchange, but some of my questions there have been downvoted. In Richard Dawkins's book "The Blind Watchmaker", in the first chapter, says "At this point some hawk-eyed philosopher will start mumbling something about a circular argument". Later on, a few paragraphs down, he says "But, however many ways there may be of being alive, it is certain that there are vastly more ways of being dead, or rather not alive." I am such a hawk-eyed philosopher. Richard Dawkins has not defined what it means to be alive. I do grant that there are many more ways of a physical system being alive rather than not alive, but this depends on the definition of life. So, my question is, has any scientist given a definition of what it means for a physical system to be alive? I am asking this question because Richard Dawkins is usually a good thinker, but he just skirts over this circularity.
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Where's the circularity? It's not circular to not define a term.– NotThatGuyCommented Jul 25, 2023 at 9:00
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It may be good to put in: Life... has property to evolve... Further Evolution is a feature of life. So any questions people may have on the circularity are obviated. I am not sure why/how there can be any question given that Dawkins himself acknowledges it. AFAIC the circularity is a trivial corollary from the fact that physical and physics are circularly defined and Dawkins' philosophy is a particularly naive kind of physicalism– RushiCommented Jul 25, 2023 at 10:42
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On different note I posted elsewhere as joke: From an old comment Mathematics is really Psychology. Psychology is really Biology. Biology is really Chemistry. Chemistry is really Physics. Physics is really Mathematics. To which I add: And Computer Science is recursive, so its all these 😎 On a more serious note: recursion and circular definition are very close, but v different. CSists have worked out the nuanced distinctions. Logicians/philosophers not so much– RushiCommented Jul 25, 2023 at 11:03
4 Answers
Dawkins doesn't care about precise dickering about what is considered alive or not-alive, because his argument doesn't depend on that. Rather, this whole section is about the definition of complexity. He says:
This has been quite a long, drawn-out argument, and it is time to remind ourselves of how we got into it in the first place. We were looking for a precise way to express what we mean when we refer to something as complicated.
And then he gives his answer:
The answer we have arrived at is that complicated things have some quality, specifiable in advance, that is highly unlikely to have been acquired by random chance alone.
He also gives a more specific answer in the case of life (which he still doesn't precisely define, because it's not the point of the section):
In the case of living things, the quality that is specified in advance is, in some sense, 'proficiency'; either proficiency in a particular ability such as flying, as an aero-engineer might admire it; or proficiency in something more general, such as the ability to stave off death, or the ability to propagate genes in reproduction.
So he's saying that complexity in general is having a quality that is highly unlikely to have been acquired by chance, and he says that complexity in living things is more specifically having a proficiency at something.
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Complexity has a quality that is specifiable in advance. IMHO That seems like a circular or "it takes one to know one" argument– user64314Commented Jul 25, 2023 at 4:30
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@StevanV.Saban It is a bit vague, but I'll tell you how I would read it. There's a limited amount of qualities we can specify in advance, because we don't have too much time to stand around specifying things. We don't have time to specify 10^300 qualities in advance, for example. So we'll only specify some smaller number of qualities, perhaps 1000, perhaps 1 million, where it is highly unlikely that a system would have any of them by pure chance. If a system does happen to have one of those million unlikely qualities, Dawkins says it has complexity.– causative ♦Commented Jul 25, 2023 at 4:41
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@StevanV.Saban To put it another way, there's a truly vast high-dimensional space of all system configurations. We humans pre-select a tiny tiny corner of this space that is of interest to us. This tiny corner is incredibly unlikely to arise by pure chance, because it makes up such a small amount of the total space of system configurations. So, if a system happens to be configured as part of this "tiny space of interest" (where it couldn't have done so by chance), Dawkins says it is complex.– causative ♦Commented Jul 25, 2023 at 4:44
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1In a minimum-description-length framework, it almost seems like he's saying that things with short description lengths are complex, but I don't think that's quite it. Empty space has a short description length but Dawkins wouldn't say it is complex, and he would say that empty space could arise by chance. So we might suppose two probability distributions: one based on human minimum-description-length of things that are of interest to us, and a second one saying what is likely to happen "by chance" in a mechanistic universe.– causative ♦Commented Jul 25, 2023 at 4:58
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1Dawkins' view might then be framed as saying, that something is complex if it is unlikely according to the "by-chance-in-a-mechanistic-universe" probability distribution, but likely according to the human "minimum-description-length" probability distribution.– causative ♦Commented Jul 25, 2023 at 4:59
So, my question is, has any scientist given a definition of what it means for a physical system to be alive?
Yes.
Any encyclopedia will give you an overview of common frameworks of necessary and sufficient characteristics of life according to biologists. From WP:
- Homeostasis: regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature
- Organisation: being structurally composed of one or more cells – the basic units of life
- Metabolism: transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organisation (homeostasis) and to produce the other phenomena associated with life.
- Growth: maintenance of a higher rate of anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
- Adaptation: the evolutionary process whereby an organism becomes better able to live in its habitat or habitats.
- Response to stimuli: a response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion; for example, the leaves of a plant turning toward the sun (phototropism), and chemotaxis.
- Reproduction: the ability to produce new individual organisms, either asexually from a single parent organism or sexually from two parent organisms.
While I'm not certain why Dawkins excluded the inclusion of these characteristics (which are often taught in elementary school), it's most likely a presumption that this framework which is relatively uniform among biologists, is presumed in discussion. I was able to recite these in junior high school, so like Dawkins, I am liable to presume that everyone is familiar with these; I find it odd, right or wrong, that someone interested in biological matters is unfamiliar with this list (and some of the debate that has occurred edge-cases like viruses and the like).
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Supplemental comment. Science is able to operate on fuzzy definitions, and instead use a list of characteristic features of a phenomenon in question. The lack of all features, and the fuzziness of the feature definitions themselves, just come with the territory for any pragmatic empiricist. The conflict with philosophers is that the dominant school of philosophy today is analyticity, where precise definitions are required. A checklist like this will not be precise enough to do linguistic and logical analytic philosophy with.– DcleveCommented Jul 25, 2023 at 15:07
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@Dcleve My dissent is that "the checklist is not precise enough to do philosophy". I would argue that the whole point of doing philosophy is to practice it where the precision is lacking and to firm up the lack of precision, first with metaphysical speculation, then with scientific hypothesis. Natural philosophy hasn't gone anywhere; it has merely prefixed itself to methodological naturalism, and despite many scientists' ignorance of this fact, natural philosophy is still a series of metaphysical presumptions which subtend the various scientific methods.– J DCommented Jul 25, 2023 at 15:37
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My complaint is that scientists wander in and pronounce their scientific conclusions as definitive and incapable of having alternative metaphysical approaches. While I advocate scientism, it has to be a voluntary acknowledgement that it is a choice, and not the one-true-way to have knowledge.– J DCommented Jul 25, 2023 at 15:39
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JD — I want philosophy to ditch rationalism and embrace pragmatism instead. Pragmatism can work just fine with a description rather than precise definitions. And the principles of methodological naturalism are readily extended into philosophy. Scientism? Aren’t you rejecting its core principle if you accept there are other ways to achieve knowledge?– DcleveCommented Jul 25, 2023 at 19:48
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@Dcleve I find that to be curiously close to my position that science accept that rationalism and foundationalism are not the only strictures by which a scientific model can be built, and that the variety of metaphysical presuppositions that lend themselves to description as natural philosophy are broad enough to accommodate the plurality of scientific methods in the same way a logician has to let go of the Laws of Thought. Yet, that plurality has to accept that for some, scientific thought isn't possible, so while some formulations of science are better than others, and science is better...– J DCommented Jul 25, 2023 at 20:26
While Dawkins should have offered a clearer definition of life upfront, his core argument can still be defended. Firstly, the probabilistic claim does not require a perfect definition of life, just identifying conditions that vastly limit the possibility space for living systems to arise by chance. Any plausible working definition serves this purpose.
Secondly, Dawkins could argue that there are certain uncontroversial aspects of living systems - such as complex organized structure, information storage and processing, metabolism, homeostasis, and reproduction with variation. Pointing out the sheer improbability of these features spontaneously emerging supports his overall reasoning.
One could grant the lack of a consensus definition of life, but still accept that any proposed definition will have prerequisites like functional complexity and information control. These make abiogenesis ridiculously improbable based on chance alone.
Dawkins was primarily opposing the analogy of biological life arising by chance as similar to a watch arising from shaking parts. He could maintain that this analogy fails even given the difficulty of precisely defining life. The clear difference in complexity between biological systems and a mechanical watch still stands per any reasonable definition.
It is not a circular argument. It is based on reality. It is clear that the universe is at the very least not brimming with life as we have seen with direct observation. So regardless of what kinds of life there might be, we know for certain that it does not commonly occur.
One doesn’t need to define what life exactly is. One just needs to accept that whatever we have seen so far in the universe outside of our earth is not life. Once you accept this, his statement stands.