What is the name of the fallacy: "If you buy XXX, which is expensive, then you would also buy YYY, because if you spent so much on XXX then you would spend as much on YYY."

The fallacy implies that both things should go together because both are expensive, and if one person has money for one, he also has money for the other.

For example, "You would never buy caviar if you don't also buy silver plates." It is false because a person may have just enough money to buy caviar, and want to know how it tastes, but if he also were to buy silver plates, he would not have enough money to taste the caviar.

  • I made some edits which you may roll back or continue editing. Welcome to Philosophy! – Frank Hubeny Jan 7 '19 at 17:45
  • This just seems like the suppressed premise that these two things are equally desirable to everyone, and that purchases are independent. Excessive uniformity and presumed independence are very common suppressed premises. They are components of the Gambler's fallacy, but that is not the form they take here. – user9166 Jan 7 '19 at 18:00
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    I had to re-learn some of how to manage money when I realized that I had enough money to get anything I wanted, but not enough to get everything I wanted. – David Thornley Jan 7 '19 at 22:58
  • This may not be a fallacy but perfectly true: 'I have a Victorian silver knife and fork, so I must get and will buy Victorian silver dessert and soup spoons to match'. Only, it is a bare psychological generalisation. Of whom it holds true, and in respect of what things, is impossible to say on the evidence given. – Geoffrey Thomas Feb 6 '19 at 19:50

This seems to be a variation on "All horses are the same color". In other words, it is incorrect induction, where the base case is that you have already bought something expensive. The fallacy is in the inductive hypothesis that you will therefore buy another expensive thing, which does not necessarily follow (in contrast to correct induction, where we can show recursively that the hypothesis does hold in general).


Bo Bennett describes pseudo-logical fallacies as those which fail his test of being true fallacies. His test has three criteria:

  1. It must be an error in reasoning, not a factual error.
  2. It must be commonly applied to an argument either in the form of the argument or the interpretation of the argument.
  3. It must be deceptive in that it often fools the average adult.

Here is a description of the situation that may be a fallacy:


This may be more of a factual error than an error in reasoning itself. Also it may not be commonly used in an argument nor deceptive. On the surface this does not appear to be fallacious.

That doesn't mean people haven't named something like this as a fallacy. In his page on what he considers pseudo-logical fallacies Bennett lists a couple named pseudo-fallacies that might fit this description:

Essentializing Fallacy: Suggesting that something is what it is and it will always be that way when in fact, that is not the case. This is simply factually incorrect.

Faulty Sign: Incorrectly assumes that one event or phenomenon is a reliable indicator or predictor of another event or phenomenon. This is very similar to many of the fallacies related to causality. This name is rarely used.

Bo Bennett, "Pseudo-Logical Fallacies" Logically Fallacious https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/6/Pseudo-Logical-Fallacies

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