In most casual English conversation, “chemical” is implied as “[man made] chemical”, though I will admit that may not be obvious to people for whom English is not a first language. It’s obvious to (almost) any native speaker what is being said, and to willfully ignore that is to be pedantic for the sake of arguing.
So which of the following count as "man made" chemicals?
Alcohol or vinegar from humans intentionally fermenting things?
A metallic aluminum alloy?
Sulfuric acid (which sometimes occurs naturally)?
Turpentine?
Soda-lime glass?
I get that it generally refers to substances that are more on the very artificial side, requiring advanced knowledge of chemistry to produce, and to have a connotation of harmfulness / toxicity. But it's not at all obvious what the speaker would consider to be a "chemical" because that varies from speaker to speaker.
Often, yes: novel compounds can have side effects which take years to understand (e.g. DDT‘a impact on bird populations lasted past the point where its effectiveness was rapidly tapering) and depending on what characteristics something was picked for you can end up with something which doesn’t biodegrade and is thus a long-term problem if it doesn’t turn out to be harmless.
The fact that these are man-made is irrelevant to their harmful effects and framing it as if it was contributes to the persistence of the natural fallacy.
The natural fallacy application doesn’t seem appropriate: the problem isn’t where they were produced but rather that they’ve never before been part of the ecosystem. We’d have the same concerns if these novel chemicals were introduced by meteors or something but that’s extremely rare whereas chemists produce a wide range of compounds every year.
That’s exactly what I’m saying. But the context is that most people operate with heuristics of the natural fallacy type. Hence this is not mere pedantry for pedantry’s sake, the intention is to provide an actually-helpful clarification/correction.
It’s a good question and in my opinion, it depends entirely on the compound.
But that wasn’t the point of my comment. I am calling out people being pedantic and nitpicky just to argue, instead of recognizing the very obvious intent of the great-grand parent’s comment and debating something with merits, like whether man made chemicals are inherently bad.
I don’t think that is what people are suggesting. Rather, man made is unknown. At least the long term affects are. We can confidently say that natural chemicals, even if they’re bad for you, likely won’t have a giant, unexpected impact on the world. Whereas there are a lot of man-made chemicals that are likely harmless. But less is know about the long term affects of injecting it in to all of earth’s various natural systems.
For many people, yes. It's also a very common belief that one and the same state of the environment is bad if traceable to human actions, but good otherwise.
The working premise in many environmental discussions is that humans carry an inherent moral taint and whatever they do creates a problem that needs to be corrected, because it came from an evil source, regardless of whether the resulting state of the world is good or bad.
