Spontaneous Generation

Here we have yet another case in which a discovery was possible for a long time before it was actually accepted. Aristotle is the villain here: he clearly endorses spontaneous generation of many plants and animals. On the other hand, I don’t remember him saying that people should accept all of his conclusions uncritically and without further experimentation for the next couple of thousand years, which is what happened. So maybe we’re all guilty.

Real progress on this question only shows up in the 17th century, with Harvey’s slogan “omnia ex ovo” and Francisco Redi’s experiments on the origin of maggots.  In the 18th century, Needham’s and Spallanzani’s experiments with boiled broths further discredited abiogeneis, but the issue was not settled until Pasteur found a way of exposing boiled broths to pure air in 1859.

Part of the funny here (not even counting practical experience) is that almost every educated man over these two millennia had read, and indeed studied deeply, a work with a fairly clear statement of the actual fly->egg->maggot->fly process. As I as I can tell, only one person (Redi) seems to have picked up on this.

“But the more Achilles gazed, the greater rose his desire for vengeance, and his eyes flashed terribly, like coals beneath his lids, as he lifted the god’s marvellous gifts and exulted.  When he had looked his fill on their splendour, he spoke to Thetis winged words; ‘Mother, the god grants me a gift fit for the immortals, such as no mortal smith could fashion. Now I shall arm myself for war.  Yet I fear lest flies infest the wounds the bronze blades made, and maggots breed in the corpse of brave Patroclus, and now his life is fled, rot the flesh, and disfigure all his body.’ ”

You’d think a blind man would have noticed this.

Anyhow, the lesson is clear.  Low hanging fruit can persist for a long time if the conventional wisdom is wrong – and sometimes it is.

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26 Responses to Spontaneous Generation

  1. dearieme says:

    But is anything low hanging fruit except in retrospect? Aren’t all low hanging fruit arguments circular?

  2. gcochran9 says:

    Look,if I could find out the sort of places that I usually misplace my keys – if I did, which I don’t – I could find the keys more easily the next time I lose them. If you find out that practitioners of a given field are not very competent, it marks that field as a likely place to look for relatively easy discovery. Thus medicine is a promising field, because on the whole doctors are not terribly good investigators. For example, none of the drugs developed for Alzheimers have worked at all, which suggests that our ideas on the causation of Alzheimers are likely wrong. Which suggests that it may (repeat may) be possible to make good progress on Alzheimers, either by an entirely empirical approach, which is way underrated nowadays, or by dumping the current explanation, finding a better one, and applying it.

    You could start by looking at basic notions of field X and asking yourself: How do we really know that? Is there serious statistical evidence? Does that notion even accord with basic theory? This sort of checking is entirely possible. In most of the social sciences, we don’t, there isn’t, and it doesn’t.

    • ziel says:

      My impression is that nowadays (the last ~25 years), when the conventional avenue of research or treatment fails to yield positive results, the response is to double down.

    • Michael 2 says:

      There is a lot of anecdotal evidence that the paleo diet greatly diminishes the symptoms of numerous diseases. Search “paleo diet” “disease name” for evidence. This looks like low hanging fruit to me.

  3. erica says:

    I’d think there’d be some “low hanging fruit” that explains atherosclerosis by now. Anything new there yet and if so, reason why?

  4. erica says:

    Sorry–should read, “Anything new there yet, and if not, reason why?” Are we still looking in the wrong places?

    • Greying Wanderer says:

      Pure guess but i wonder if lactose persistence isn’t unusual in the sense that populations have a habit of evolving beneficial traits related to their local diet if they ate the same things long enough in which case if i had any ailment that could possibly be related to diet i’d look at what my ancestors ate where they lived i.e. olive oil might be great for people of Italian descent and butter not so great (on average) and vice versa for Irish descent. Maybe?

  5. j says:

    Aristoteles was less dumb than you arrogantly pretend. He still has followers in the academy that teach that all of us, give or take a billion years, sprung to life from the mud. By spontaneous generation.

    • Cubano says:

      People consider for example the ancient idea of the “atom” a huge visionary achievement by the Greeks. I’d point out that it was one of many ideas circling at the time, that happened to be “almost” true as discovered 2000 years later. “Almost” because the atom IS divisible after all. And they were not those tiny particles that they could see swirling in the air inside the rooms.
      It seems to me that Aristoteles was referring to the everyday emergence of dirty bugs, not to the ultimate origin of life, that was obviously brought about by Gaia or Zeus. So no, I don’t think we got it right there.

  6. bob sykes says:

    J is right. The basic theory of modern biology is that life arose by spontaneous generation some 3.8 Bya. Supposedly, it does not occur today. Needham, Spallanzani and Pasteur, however, did not exhaust all possibilities.

    Aristotle is justly famous as one of the greatest of all philosophers, including his work on biology, which is still worth reading. If there is any part of his science that is no longer relevant it is his mechanics, which is quite primitive and based on common sense intuitions. But Aristotle was a much better informed and more intelligent man than virtually any modern university faculty member, and the great bulk of his work is worth knowing and largely correct.

  7. Jim says:

    Aristotle was no doubt wrong on many things but modern criticism of him and other ancient Greek thinkers often overlooks a crucial distinction between them and most earlier thinkers. For example Aristotle explained earthquakes as being due to the collapse of underground caverns. Now factually this explanation is completely wrong but notice that it is a completely naturalistic explanation. Before this time most explanations of natural phenomena were animistic. Earthquakes were caused by an angry Neptune shaking the ground or something like that.

    The science of the ancient Greeks was often crude and naive but they made a remarkable transition from regarding reality as subject to the whims of gods and spirits to regarding it as the domain of unchanging and eternal natural law. This was a huge advance.

  8. Deckin says:

    Since there’s finally a topic that I know something about, I think I add both some more low hanging fruit and some more about Aristotelian science. Empedocles (a pre-Socratic) actually had a theory of evolution through not badly thought out simulacra of random mutation and selective (even sexual!) sweeps. Aristotle, ever the observationally driven thinker, rejects Empedocles not on a priori grounds, but, rather, because he can find no evidence of any mutations. Given the evidence at the time, it doesn’t seem like an absurd posterior probability to come to, but the wonder is Empedocles mostly a priori arrival at evolution. Why wasn’t this fruit picked up until Wallace and Darwin?

  9. teageegeepea says:

    I suppose Aristotle seems wiser than some other philosophers, but is that saying much?

    Steve Dutch discusses problems with the reasoning of Aristotle’s “On the Heavens” here, but in modern times it seems sort of pointless to expend the effort.

  10. dearieme says:

    Who will be first to identify the infectious micro-organism(s) behind the dramatic rise and fall of heart attacks over the last 90 years or so?

    • dearieme says:

      Come to think of it, if it is about 90 years, two hypotheses. (i) It could have started up with the cross infections caused by the upheavals of WWI, or (ii) It’s the Spanish Flu that’s behind it.

      There you are, chaps: go to it.

  11. Jim says:

    I took just a quick look at Dutch’s post on Aristotle. I’m not very interested in combing through the fine details of either Dutch’s or Aristotle’s reasonings. However obviously if someone wants to nitpick Aristotle’s writings in such detail then in fairness to Aristotle they ought to read the Greek text and not rely on translations.

    The big picture here is that the ancient Greek philosophers such as Aristotle had moved from an animistic view of reality to an essentially naturalistic and scientific view. This seems to me to be the important thing about them not the fact that their science appears pretty naive looking back at it from 2000 years in the future.

  12. Sean says:

    Ancient Greeks knew about fasting. Animals do it when they are sick. A couple of one day long fasts a week looks promising according to Mark Mattson. Mattson doesn’t think infection is the major cause of Alzheimers

  13. Anonymous says:

    Emerging roles of pathogens in Alzheimers
    http://www.ncbi.nlm.nih.gov/pubmed/21933454

  14. Sean says:

    It’s not news that infection can do things – in a dish or in fat lab mice, but it is not thought to be the major cause of Alzheimers in humans.
    On the other hand read about how Pyrazinamide failed to work on TB when tested in the dish and mice from a fascinating Slate article The Mouse Trap, parts 2 & 3 are great too.

  15. Jake says:

    I wonder if you might be reading too much into the quoted passage. As stated, ‘flies infest the wounds the bronze blades made, and maggots breed in the corpse’ does not necessarily imply any causative relationship between flies and maggots, only that they are both generally present in corpses. Without a statement like ‘flies lay their eggs in the wounds, which then grow into maggots,’ the passage is ambiguous. Your point is well taken and I’m certain there are many illustrative examples (anyone remember the TV show ‘Connections’?), but I’m not sure this is the best one.

  16. The Man Who Was . . . says:

    Extrapolating from Jon Haidt, most people in most societies have an enormous, indeed a religious, respect for authority, to the point where you basically just don`t question it. So even if Aristotle didn`t believe in authority worship and didn`t want to be taken as such an authrority, he was so accomplished that people just did so anyway. Something similar happened in medicine with Hippocrates, who seems to have been something close to a modern scientific rationalist in his own practice, but whose work was taken almost as scripture. This seems weird to a lot of us, even if we`re personally religious, but it does seem to be more of the human norm.

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