This is an argument that shows up a lot. An action X, which is actually good, is deemed to be bad, because if X was coupled with something else, Y, then things would be very bad. Hence, since X gets us halfway towards this very bad state, X itself must be bad (assume that the goodness of X is far insignificant compared to the badness of X and Y together).

Is this argument sound? Is it a fallacy?

I have a hard time figuring it out. I think it kind of comes down to whether the goodness of X outweighs the increased probability of ending up in an "X and Y"-situation? So perhaps the flaw in the argument is that it assumes everybody is as risk averse as the one making the argument? And, in fact, a further flaw is that the argument does not actually argue what the exact or estimated increase in probability is, thus the argument is also incomplete?

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    I mean, not only is it not sound but it isn't even valid. You go from A to ~A (x is good to x is not good). That is a direct contraction, the premises are true but the conclusion is false, so it is not valid or sound. If you want something more interesting, remove the "x is good" premise, so you have "x and y are bad, therefore x is bad" which im pretty sure is an informal fallacy and has a name but I can't think of it off the top of my head. But what you have written is a direct contradiction and is not valid or sound.
    – Not_Here
    Aug 22, 2017 at 12:14
  • It's not a contradiction, the argument essentially just says that there's something "else" about X that you've forgotten, and that's what makes it bad. You are getting hung up on semantics. The person making the argument agrees that if that something "else" did not exist, then X would be good.
    – Vase
    Aug 22, 2017 at 12:20
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    I'm not getting hung up on semantics, I'm pointing out the logical syntax of the argument you are presenting. You asked if the argument is a fallacy or if it is sound, those are technical terms from logic that have meaning. Things that result in a contradiction are not valid or sound. "x is bad" is the opposite of "x is good", therefore, if your argument starts with "x is good" and ends with "x is bad" you have a contradiction. If you are not asking about actual logic then you shouldn't use the terms fallacy and soundness.
    – Not_Here
    Aug 22, 2017 at 12:25
  • I love talking in the abstract as much as the next guy, but Not_Here is completely correct. If you provide an example I think you will find that you need a factor 'z' as well, to make this work. Aug 23, 2017 at 12:55

3 Answers 3


Arguments that often show up are not necessarily correct. Compare the frequent mistake of reverting an implication. According to my experience, in particular politicians and journalists often conclude that from "If A then B" it follows that "If B then A".

First your argument assumes that Y is a (necessary or very probable) consequence of X. That is not always the case.

Here is a simple example. Let X: You are jogging. That's good: Sports in fresh air. Let Y: You are killed while jogging. Is jogging bad now? No. It was not X that got you half way to Y. It was the presence of a murderer who also might have caught you at home.

But even if Y is a consequence of X you cannot blame X of being bad.

Here is the simplest example: Let X: You are living. Let Y: You will die. Is living bad for that sake?

  • Surely, if "It was not X that got you half way to Y", then that is not the example OP is thinking of. Aug 23, 2017 at 12:50
  • @ChrisWohlert: Then at a minimum, the OP's argument is incomplete.
    – cHao
    Aug 24, 2017 at 21:19
  • @Heinrich, That's correct. Aug 25, 2017 at 7:46

This may be a fallacy of irrelevant reason because the premise contains "if X is combined with Y", which does not justify the conclusion that X is bad. In other words, it is hard to accept that X is bad based on the given premise. However, if the premise stated that X is always combined with Y which in turn always leads to something very bad, then the conclusion that X is bad could be more easily accepted.

I think it looks like this: X is good, Y is (unknown), X + Y = very bad, good + unknown = very bad. Therefore, X remains good.


I think you might be torn between two different kinds of arguments.

There's the explicit deductive statement: "X, Y is bad. Therefore X is bad."

This is plainly a logical fallacy because the consequent simply does not follow from the premise.

However, there's also the inductive statement: "X,Y is bad. X brings us closer to X,Y. So X is likely to be bad."

The latter kind of statement doesn't directly impose the properties of X,Y on X based on a false association. It also cannot be a logical fallacy because it doesn't presume to make a deductive statement. It's an inductive statement, so that's when we can argue about things like probability, and render our opinions. That kind of statement can still range from reasonable ("it's bad to own a a gun without training because you might misfire") to ridiculous ("if you get a gun without training you might go into an unconscious ballistic trance and commit a mass-murder against your will"), but in neither case is a logical fallacy committed.

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