What is the name of this fallacy (if it is indeed a fallacy):

  1. Drinking alcohol makes me laugh
  2. Laughing is good for me
  3. Therefore drinking alcohol is good for me

Assuming the premises are true then the conclusion is true, but surely there are many more factors to consider (rather than just whether it makes me laugh) in order to understand if drinking alcohol is actually good for me or not.

Maybe it affects my health etc so surely I can’t conclude that drinking alcohol is good for me based on this one argument. But it’s deductive so if the premises are true then so is the conclusion.

Thanks in advance

  • "One-sided argument (also known as card stacking, stacking the deck, ignoring the counterevidence, slanting, and suppressed evidence) is an informal fallacy that occurs when only the reasons supporting a proposition are supplied, while all reasons opposing it are omitted", Wikipedia. It is enabled here by equivocation on "good". It is used in a restricted sense in 2. (other things being equal), but an unrestricted sense is implied in 3.
    – Conifold
    Apr 7 at 18:01
  • I think there’s quite a lot wrong in that argument. (1) is simply a false statement, as alcohol can cause a heart attack/stroke, neither of which involve laughter. You are committing a correlation implies causation (alcohol implies laughter) fallacy. And linguistically, the “good for me” in (2) does not mean the same as the “good for me” in (3), so (3) doesn’t follow from (1) and (2), unless by “drinking alcohol is good for me”, you meant exactly the same “good for me” as in (2), which I doubt. Apr 8 at 0:32
  • "Love is like a bottle of gin. But a bottle of gin, is not like love."
    – CriglCragl
    Apr 8 at 23:07

Besides Conifold's mentioned usual "cherry pick" informal fallacy, as you emphasized assuming the premises are true, this could be counted as a strict formal Modal Fallacy if you interpret you last conclusion as "drinking alcohol is necessarily good for me". In model logic:

It is the fallacy of placing a proposition in the wrong modal scope, most commonly confusing the scope of what is necessarily true. A statement is considered necessarily true if and only if it is impossible for the statement to be untrue and that there is no situation that would cause the statement to be false. Some philosophers further argue that a necessarily true statement must be true in all possible worlds.

In modal logic, a proposition can be necessarily true or false, meaning that it is logically necessary that it is true or false; or it could be possibly true or false, meaning that it is true or false, but it is not logically necessary that it is so: its truth or falseness is contingent. The modal fallacy occurs when there is a confusion of the distinction between the two.

Your above transitive chain of self-assumed deductive arguments only holds with ceteris paribus (all other things being equal and assuming your premises are all true). But in reality (all possible worlds under modal logic perspective), many other conditions will cause goodness for you too.

If you interpret drinking alcohol is good for you sufficiently all other things being equal, just momentarily confused yourself into believing you have to drink alcohol, and later you clearly realized drinking alcohol most likely also does harm to you simultaneously from your above description. Now you should realize there's actually no fallacy or logic issue at all, since "good to me" by no means contradicts with "does harm to me" simultaneously under common English usage. Your body just receives both effects simultaneously (goodness caused by laughing/relaxing, harm caused by intoxication)...

If you still feel uneasy at this point, then I suggest that comes from the informal equivocation fallacy of the exact meaning of "good for me" in your assumed correct 2nd premise, you cannot simply assume the absolute correctness of your 2nd premise regarding the exact meaning of "good for me". You have to explicitly specify whether this goodness means net overall good effect or a specific good effect...


The problem is that "laughing is good for me" is very imprecise. Change this to "If we add all the effects of laughing on my physical and mental health, societal status and anything else that is relevant, then all added together, laughing does me more good than bad".

Now it is very clear that the conclusion is not right. Because drinking alcohol makes you laugh which is overall doing you more good than bad, but without any contrary evidence, we should assume that drinking alcohol may have more effects, which may be overall bad, so we cannot conclude that drinking alcohol is overall good for you.


An economist would say that this a fallacy of composition but this is more or less in the sense that Conifold spoke of equivocation around "good".

Basically alcohol has some good and some bad properties.

One can form a similar one-sided argument for the bad properties

  • Drinking alcohol makes me drive poorly.
  • Driving poorly is bad for me (because e.g. I can crash my car or hurt someone and go to jail.)
  • Therefore drinking alcohol is bad for me.

The fallacy of composition here is that alcohol has some good and some bad properties, and we're (sort of) inferring that because it has some good ones (which are only part of its properties) that it's just good [for someone] overall. I say "sort of", because in your inference there isn't actually the conclusion "alcohol is always good for me" (or "alcohol is never bad for me"), but that's an implied reading when nothing else is said. It's a psychological trick (often done in marketing) that if you only present the good side of something, its bad side may be ignored by the hearer.

In general, when the fallacy of composition is presented, it's usually in terms of actual physical parts like e.g. the parts of a car. But it applies just as well to properties. You can't conclude that a car is made of rubber because its tires are. Likewise you can't conclude alcohol is good overall just because it has some good properties, like making you laugh.

This without even talking about the temporal equivocation around "is good" or "is bad". Something can be/feel good now but have bad effects later. (You may have a laughter now but a headache next morning. Etc.) This last part is called short-termism or short-sightedness/myopia (by economists). It's not as much a logical fallacy as it is a problem of (intertemporal) utility, which is slightly outside the realm of what logic usually deals with.

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