And hamburgers (which the body cannot synthesize).

> At worst, it implies that, like essential amino acids, it CAN be synthesized by some living organism.

It does not imply that.

In terms of a logical implication P -> Q, certainly not.

Rhetorically, it does have that interpretation.

When some unconditional proposition is presented together with some red herring conditions, a less informed reader may take the interpretation that the conditions are relevant; i.e. that it is falsified when the stated conditions do not hold. Because, why would the presenting expert include irrelevant conditions?

"I've noticed that Smith doesn't beat his wife in public."

That doesn't logically imply Smith beats his wife, but he does have to be beating his wife for the "in public" condition to be relevant. To assume that the condition is relevant is to assume that Smith does beat his wife. If the condition is not relevant, why is it there?

I'd like to be able to assume that all conditions given in serious writing about STEM subjects are relevant, so I don't have to waste my time suspecting they are not.

But it __is__ relevant to the article that iodine cannot be synthesized by the human body ...

it does say something useful. it points out that iodine can't be synthesized in our bodies.

the fact it doesn't add more, possibly irrelevant, information does not diminish its usefulness.

it does not imply anything about things that aren't being discussed. it's abnormal to read everything with a qualification like "in our bodies" as a implication of some other hidden meaning.

as technical people we probably enjoy delving into tangents and pedantry far too much. but, for example, adding a statement "... In fact, iodine is an element and cannot be synthesized ... " would be a tangent and should be avoided or edited out.

> it's abnormal to read everything with a qualification like "in our bodies" as a implication of some other hidden meaning.

It is absolutely normal to read every condition given in some technical subject matter as being relevant, and decent writing satisfies this.

It takes extraordinary effort to maintain a constant suspicion that every stated condition might be irrelevant to the proposition to which it is attached.

that doesn't mean, as the GP comment said and i'm objecting to, that it implies anything about when the condition is false.

this is a magazine article, not a proof. so i'm certain the author felt it was relevant to say it that way because the whole article is about what happens in the body, whether or not it was logically relevant to the condition.

the fact that he made a narrower than necessary true statement does not imply he meant anything beyond that either, even if you read it pedantically. it takes extraordinary effort to maintain a constant suspicion that every unstated condition might be relevant too.

Using what definition of "implies"? From formal logic, or the rhetorical implies?

both. either.

Not only is it useful, but it gets straight to the point by presenting exactly what is needed in this context (“it is not synthesized by our bodies”) without getting bogged down by explanations (“because it is an element”). It efficiently delivers the required information. You may not personally like the style, but that doesn’t mean there’s anything wrong with it.