6 ms·

Isn't the entire field of medical science just a list of things we've managed to do for the body that evolution failed to manage over the course of billennia?

Retric 4y ago
No, the majority of health issues are personal. Evolution optimizes species not individuals, so while some kids need glasses most kids don’t. Evolution’s response to massive physical trauma can be things like wariness of heights rather than a body that can fall arbitrarily distances.
- dheera 4y ago
  It weren't for medical science I'd be dead multiple times over by now due to causes that someone with better genes would have survived. > Evolution’s response to massive physical trauma can be things like wariness of heights rather than a body that can fall arbitrarily distances. It can be either or both. Cats tend to survive falls very well, as do insects, but for different reasons.
- AlecSchueler 4y ago
  I don't really get the distinction. I do get your point but x% of a species needing glasses is a species level error. And our entire species was susceptible to things like smallpox before we had vaccines for that stuff.
  - Retric 4y ago
    The threshold where kids “need glasses” isn’t the same threshold where people would be unable to survive in the wild without them. Also, species level survival is based around fairly large families you see before birth control. Not everyone needs to make it.
    - AlecSchueler 4y ago
      That's the point though: we have much better infant mortality rate now, and the kids who grow up don't need to worry about their eyesight etc., ergo we're doing better than evolution alone.
      - Retric 4y ago
        Better by our own yardstick, but evolution can get plenty of people to adulthood without any medical issues. A frog egg would presumably prefer an evolutionary strategy that involved fewer eggs and a more caring parent. However, the willingness to fail allows for more long term flexibility. Which is presumably why many species place their young in an immediate live or death struggle with their siblings.
- digging 4y ago
  To be more accurate, evolution optimizes populations, not species. Anyway - there are dangers we've evolved resistance to. We have powerful immune systems that fights off tons of diseases. But they fail against some diseases, and medicine helps us there (sometimes). Some of these diseases are extremely widespread and threaten populations. Am I misunderstanding your comment?
  - Retric 4y ago
    Largely yes, but I would point out that humanities resistance to disease is vastly better than individual resistance to disease. For example Rabies has close to 100% fatality rate when untreated and has been a threat for vastly longer, but COVID more people over the last 100 years. So what’s a serious threat to an individual doesn’t necessarily mean a major threat to a larger population. In that context there was likely significant protection offered by our aversion to the ill when we were primitive tribes with limited contact to each other. Such aversion could act as an external immune system causing most excessively deadly to burn out and pushing for ever less deadly strains over time.
    - digging 4y ago
      Fair points. But do we actually have a biological aversion to illness? That strikes me as cultural (and fairly recent). I understand things like leper colonies to be exceptional, not typical. We've had various theories of disease before scientific ones and they mostly didn't consider contagion.
      - Retric 4y ago
        There’s competing reactions, taking care of sick family/tribe members has obvious benefits and prior exposure is likely. Anyway, it’s hard to say how much of this is cultural, but multiple cross cultural aversions at least have the side effect of reducing contact with disease. “Pathogen avoidance: Uncanny stimuli may activate a cognitive mechanism that originally evolved to motivate the avoidance of potential sources of pathogens by eliciting a disgust response. "The more human an organism looks, the stronger the aversion to its defects, because (1) defects indicate disease, (2) more human-looking organisms are more closely related to human beings genetically, and (3) the probability of contracting disease-causing bacteria, viruses, and other parasites increases with genetic similarity."[8] The visual anomalies of androids, robots, and other animated human characters cause reactions of alarm and revulsion, similar to corpses and visibly diseased individuals.[9][10]” https://en.wikipedia.org/wiki/Uncanny_valley https://en.wikipedia.org/wiki/Uncanny_valley People’s near universal aversion to the smell of rotting flesh and human shit are similar examples. Of course at the individual level this is less universal. Another possibility is heightened pain response around minor skin damage compared to larger injuries. Aka thorns and paper cuts hurt so much because that kind of injury was actually more dangerous than moderate blunt force trauma which damages more flesh but doesn’t risk infection. PS: That said it’s not like we can actually test these theories. It’s mostly an interesting idea that seems plausible.

Retric 4y ago

No, the majority of health issues are personal. Evolution optimizes species not individuals, so while some kids need glasses most kids don’t. Evolution’s response to massive physical trauma can be things like wariness of heights rather than a body that can fall arbitrarily distances.

dheera 4y ago
It weren't for medical science I'd be dead multiple times over by now due to causes that someone with better genes would have survived. > Evolution’s response to massive physical trauma can be things like wariness of heights rather than a body that can fall arbitrarily distances. It can be either or both. Cats tend to survive falls very well, as do insects, but for different reasons.
AlecSchueler 4y ago
I don't really get the distinction. I do get your point but x% of a species needing glasses is a species level error. And our entire species was susceptible to things like smallpox before we had vaccines for that stuff.
- Retric 4y ago
  The threshold where kids “need glasses” isn’t the same threshold where people would be unable to survive in the wild without them. Also, species level survival is based around fairly large families you see before birth control. Not everyone needs to make it.
  - AlecSchueler 4y ago
    That's the point though: we have much better infant mortality rate now, and the kids who grow up don't need to worry about their eyesight etc., ergo we're doing better than evolution alone.
    - Retric 4y ago
      Better by our own yardstick, but evolution can get plenty of people to adulthood without any medical issues. A frog egg would presumably prefer an evolutionary strategy that involved fewer eggs and a more caring parent. However, the willingness to fail allows for more long term flexibility. Which is presumably why many species place their young in an immediate live or death struggle with their siblings.
digging 4y ago
To be more accurate, evolution optimizes populations, not species. Anyway - there are dangers we've evolved resistance to. We have powerful immune systems that fights off tons of diseases. But they fail against some diseases, and medicine helps us there (sometimes). Some of these diseases are extremely widespread and threaten populations. Am I misunderstanding your comment?
- Retric 4y ago
  Largely yes, but I would point out that humanities resistance to disease is vastly better than individual resistance to disease. For example Rabies has close to 100% fatality rate when untreated and has been a threat for vastly longer, but COVID more people over the last 100 years. So what’s a serious threat to an individual doesn’t necessarily mean a major threat to a larger population. In that context there was likely significant protection offered by our aversion to the ill when we were primitive tribes with limited contact to each other. Such aversion could act as an external immune system causing most excessively deadly to burn out and pushing for ever less deadly strains over time.
  - digging 4y ago
    Fair points. But do we actually have a biological aversion to illness? That strikes me as cultural (and fairly recent). I understand things like leper colonies to be exceptional, not typical. We've had various theories of disease before scientific ones and they mostly didn't consider contagion.
    - Retric 4y ago
      There’s competing reactions, taking care of sick family/tribe members has obvious benefits and prior exposure is likely. Anyway, it’s hard to say how much of this is cultural, but multiple cross cultural aversions at least have the side effect of reducing contact with disease. “Pathogen avoidance: Uncanny stimuli may activate a cognitive mechanism that originally evolved to motivate the avoidance of potential sources of pathogens by eliciting a disgust response. "The more human an organism looks, the stronger the aversion to its defects, because (1) defects indicate disease, (2) more human-looking organisms are more closely related to human beings genetically, and (3) the probability of contracting disease-causing bacteria, viruses, and other parasites increases with genetic similarity."[8] The visual anomalies of androids, robots, and other animated human characters cause reactions of alarm and revulsion, similar to corpses and visibly diseased individuals.[9][10]” https://en.wikipedia.org/wiki/Uncanny_valley https://en.wikipedia.org/wiki/Uncanny_valley People’s near universal aversion to the smell of rotting flesh and human shit are similar examples. Of course at the individual level this is less universal. Another possibility is heightened pain response around minor skin damage compared to larger injuries. Aka thorns and paper cuts hurt so much because that kind of injury was actually more dangerous than moderate blunt force trauma which damages more flesh but doesn’t risk infection. PS: That said it’s not like we can actually test these theories. It’s mostly an interesting idea that seems plausible.