- The truth or falsity of a statement is decided by the positive or negative consequences of it.
If global warming is occurring and is caused by humans, then we are obligated to do something to stop or slow it.The most effective way to do so is for businesses to cut down on carbon emissions.The short term costs of cutting carbon emissions would be economically devastating.Q.E.D: Global Warming is either not occurring, not caused by humans, or both.
- Or, conversely,
If global warming is occurring and is caused by humans, then we are obligated to do something to stop or slow it.The most effective way to do so is for businesses to cut down on carbon emissions.The long-term economic benefits of stopping global warming will be enormous.Q.E.D.: Global warming is both occurring and caused by humans.
- Ain't it fun when you can use the same fallacy and essentially the same argument and "prove" diametrically opposite conclusions?
- Lord Denning actually used this as a reason to quash the Birmingham Six's appeal against their conviction. If they were guilty, it would have been a waste of time letting them appeal to trial. If they were innocent, he argued, it means that the police must have lied and forged confessions. If the police really did lie, this would be really bad for society. Therefore, they must be guilty.
- Lord Denning was by this point beginning to show the strain of being 81 years old, and was likely doing what he always did (deciding the case on instinct and constructing a legal justification for his decision), just without his normal adeptness. The Birmingham Six's alibi was "we couldn't have done the bombing because we were going to an IRA funeral", which probably meant Denning had already decided they were guilty of something and was trying to find a way to make that law.
- Child molestation accusations, also a case of Appeal to Fear. It's horrible to have an active child molester roaming around, so people accused of child molestation are often never trusted again by society, whether there's any proof of it or not. Taking note of this trope in this instance, though, can cause the opposite problem: assuming an accused child molester is innocent when they're not, because it'd be horrible to accuse someone wrongly of child molestation. The issue is a very polarizing instance of this appeal, which is why there was (and continues to be) so much drama over Michael Jackson and Woody Allen.
- An argument for the existence of god (any god, logical fallacies aren't picky) is how much life would suck if there was no god (e.g. we would all become Straw Nihilists). Conversely, some atheists claim exactly the opposite, that life would suck if gods did exist (e.g. all of existence would be a totalitarian Dystopia). Bear in mind though, that either side isn't necessarily making this fallacy, and may just be making an observation. However, it can be hard to tell.
- Likewise, evolution is often claimed by creationists to have all sorts of horrible consequences if true, quickly summed up as "If we're descended from monkeys, then we will act like monkeys," and of course the eugenics argument. Besides most of these negative consequences being false or irrelevant (if humans are apes, then to act "like an ape" does not preclude acting like a human), the desirability of common ancestry has nothing to do with its truth value.
- Deconstruction can end up like this if done in a sloppy manner.
- Some Holocaust deniers will argue that the Holocaust being true provides a justification for the Israeli treatment of Palestinians and that it lends credence to American neoconservatives citing World War II as a model for a "just war". Of course, neither of these things affect the reality of the Holocaust.
Looks like this fallacy but isn't
- Long-term decision making. You are planning on something that cannot be proven to exist, and therefore, it is impossible for logic to come to an absolutely true conclusion about it and you can only foresee a possible consequence. Consequential arguments are generally not fallacious if used in decision making with something that cannot be objectively provable - i.e., (desirable/undesirable, or morally right/morally wrong, not is it true). There is no "real" decisive position, such as a tax rate or drug policy. This is why arguments from consequences are accepted as valid in law and ethics (e.g. utilitarianism).
- This particularly includes questions about whether or not a particular course of action is desirable. Almost inevitably, the truth or falsity of the statement "Doing X is desirable" is subjective, and almost as inevitably, the subjective truth or falsity depends in whole or in part on X's consequences.