> 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).

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marcosdumay 2 hours ago | parent [-]

> 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.

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unparagoned 2 hours ago | parent | next [-]

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 2 hours ago \| parent [-]
		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.

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customguy 2 hours ago | parent | prev [-]

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.

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Xirdus 2 hours ago | parent [-]

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 an hour ago \| parent [-]
		> 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-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