4 ms·

> but far less strong evidence about its actual effects. Yeah, but we shouldn't take absence of evidence as evidence of absence. The fact is that it's just rea

by zug_zug 3mo ago

> but far less strong evidence about its actual effects. Yeah, but we shouldn't take absence of evidence as evidence of absence. The fact is that it's just really really hard to establish a causal relationship, even if it's there, because of all the cofounders. Heck even if you constructed a study with a known poison, like lead, and you might not see the results in a single study. You could give 50 participants water with flint levels of lead in it for a month, and you might not get scientifically significant result just due to the wide variance in a population. Or another example is just thinking how hard it would be construct a study with a control, when every single construction material has plastics in it and they are floating in the air around us all the time (as mentioned in the article). Could it affect mental or reproductive wellbeing? Certainly. Can we construct a study to establish either way? Not easily. And one of the plasticizers they talk about, pthalates, are known to be endocrine disruptors (i.e. mess with hormones).

marcosdumay 3mo ago
> Yeah, but we shouldn't take absence of evidence as evidence of absence. That's wrong. Yes, we should. Each and every study that doesn't find evidence for what they are looking for is evidence for its absence.
- unparagoned 3mo ago
  That’s wrong. Only if the studies are powerful enough and are looking at the right stuff can you make any reasonable conclusions. If the studies are powerful enough then that absolutely isn’t evidence of absence at all.
  - Xirdus 3mo ago
    Evidence can be strong or weak. Every positive study result is evidence of presence, usually strong evidence. Every negative study result is evidence of absence, usually very weak evidence.
    - rTX5CMRXIfFG 3mo ago
      And yet, people can be extremely vigilant about a positive correlation when it doesn’t fit their personal agenda, going as far as questioning methodology in even the least pragmatic ways possible; or, become accepting of the absence of evidence as evidence of absence when weak/no correlation is convenient to their own biases.
      - Xirdus 3mo ago
        I'd say it's very sensible to assume absence up front before there's convincing evidence of presence. Sure, personal biases influence our evidence thresholds a lot, and often people demand unfair rigor that cannot be practically met. But the opposite is also true - sometimes people will believe in presence with zero evidence if they like it enough. The latter is far, far more dangerous than the former.
        rTX5CMRXIfFG 3mo ago
        It’s one thing to believe in presence with zero evidence, and another to _withhold_ judgment when there’s zero evidence. I think you may be conflating the two. Then again, perhaps we are simply two different types of people. I don’t believe that a complex system can be expected to stay the same when you introduce a new factor into it, while you prefer to adjust much later when effects appear or when evidence achieves total infallibility up to the academic level. I am risk-averse, you like taking it; I’d rather prevent, you’d rather cure. Stating that the former is “far, far more dangerous” is just begging the question though.
    - zug_zug 3mo ago
      That's not right, a negative study often still can give evidence that something is true, but it just didn't meet the p=.05 threshold.
      - Xirdus 3mo ago
        p<=0.05 is so easy to achieve for actual positive results (just increase sample size) that I don't think it's productive to treat any result with p>0.05 as positive evidence for any purpose other than deciding to rerun the study with a bigger sample size.
- customguy 3mo ago
  Absence in the results of whatever we measured for. Just take the sheer hybris of "junk DNA": We don't understand this, so it's probably junk.
  - Xirdus 3mo ago
    Note that we didn't call it junk DNA until we learned a whole lot about how DNA works and formulated a theory in which junk DNA doesn't do anything for good reasons. In a way, lack of understanding prevented us from calling it junk DNA earlier. Of course it's still possible for the theory to be wrong and the so-called junk DNA being actually important. It's only junk according to our classical, non-quantum and non-relativistic theory of junkiness.
    - customguy 3mo ago
      > Note that we didn't call it junk DNA until we learned a whole lot about how DNA works and formulated a theory in which junk DNA doesn't do anything for good reasons. In a way, lack of understanding prevented us from calling it junk DNA earlier. Thanks for noting that, you totally caught me since I actually don't even really remember the stuff I read about that, which was probably false to begin with: https://en.wikipedia.org/wiki/Junk_DNA#Junk_DNA_and_non-coding_DNA https://en.wikipedia.org/wiki/Junk_DNA#Junk_DNA_and_non-codi... So upon further consideration, since I don't really know anything about the research of the impact of microplastics, I'll apologize for speaking of scientific hybris so flimsily, that was really the hybris of the layman (me). I'm still skeptical, not of science but of the harmlessness of microplastics. Not because of any evidence I have, but because it's just so us... this cycle of putting something everywhere before we even know it exists, finding out it exists, going "nahhh it's probably fine" for years, decades or centuries, and then "oh shit". Which I'll admit is not scientific and not really a useful contribution to this conversation, either :P

by zug_zug 3mo ago

marcosdumay 3mo ago

> Yeah, but we shouldn't take absence of evidence as evidence of absence. That's wrong. Yes, we should. Each and every study that doesn't find evidence for what they are looking for is evidence for its absence.

unparagoned 3mo ago
That’s wrong. Only if the studies are powerful enough and are looking at the right stuff can you make any reasonable conclusions. If the studies are powerful enough then that absolutely isn’t evidence of absence at all.
- Xirdus 3mo ago
  Evidence can be strong or weak. Every positive study result is evidence of presence, usually strong evidence. Every negative study result is evidence of absence, usually very weak evidence.
  - rTX5CMRXIfFG 3mo ago
    And yet, people can be extremely vigilant about a positive correlation when it doesn’t fit their personal agenda, going as far as questioning methodology in even the least pragmatic ways possible; or, become accepting of the absence of evidence as evidence of absence when weak/no correlation is convenient to their own biases.
    - Xirdus 3mo ago
      I'd say it's very sensible to assume absence up front before there's convincing evidence of presence. Sure, personal biases influence our evidence thresholds a lot, and often people demand unfair rigor that cannot be practically met. But the opposite is also true - sometimes people will believe in presence with zero evidence if they like it enough. The latter is far, far more dangerous than the former.
      - rTX5CMRXIfFG 3mo ago
        It’s one thing to believe in presence with zero evidence, and another to _withhold_ judgment when there’s zero evidence. I think you may be conflating the two. Then again, perhaps we are simply two different types of people. I don’t believe that a complex system can be expected to stay the same when you introduce a new factor into it, while you prefer to adjust much later when effects appear or when evidence achieves total infallibility up to the academic level. I am risk-averse, you like taking it; I’d rather prevent, you’d rather cure. Stating that the former is “far, far more dangerous” is just begging the question though.
  - zug_zug 3mo ago
    That's not right, a negative study often still can give evidence that something is true, but it just didn't meet the p=.05 threshold.
    - Xirdus 3mo ago
      p<=0.05 is so easy to achieve for actual positive results (just increase sample size) that I don't think it's productive to treat any result with p>0.05 as positive evidence for any purpose other than deciding to rerun the study with a bigger sample size.
customguy 3mo ago
Absence in the results of whatever we measured for. Just take the sheer hybris of "junk DNA": We don't understand this, so it's probably junk.
- Xirdus 3mo ago
  Note that we didn't call it junk DNA until we learned a whole lot about how DNA works and formulated a theory in which junk DNA doesn't do anything for good reasons. In a way, lack of understanding prevented us from calling it junk DNA earlier. Of course it's still possible for the theory to be wrong and the so-called junk DNA being actually important. It's only junk according to our classical, non-quantum and non-relativistic theory of junkiness.
  - customguy 3mo ago
    > Note that we didn't call it junk DNA until we learned a whole lot about how DNA works and formulated a theory in which junk DNA doesn't do anything for good reasons. In a way, lack of understanding prevented us from calling it junk DNA earlier. Thanks for noting that, you totally caught me since I actually don't even really remember the stuff I read about that, which was probably false to begin with: https://en.wikipedia.org/wiki/Junk_DNA#Junk_DNA_and_non-coding_DNA https://en.wikipedia.org/wiki/Junk_DNA#Junk_DNA_and_non-codi... So upon further consideration, since I don't really know anything about the research of the impact of microplastics, I'll apologize for speaking of scientific hybris so flimsily, that was really the hybris of the layman (me). I'm still skeptical, not of science but of the harmlessness of microplastics. Not because of any evidence I have, but because it's just so us... this cycle of putting something everywhere before we even know it exists, finding out it exists, going "nahhh it's probably fine" for years, decades or centuries, and then "oh shit". Which I'll admit is not scientific and not really a useful contribution to this conversation, either :P