In this way, mockery can function as a "more superficially 'respectable', morally sensitive way of doing class-based distinction than less civil disgust." The philosopher Baruch Spinoza took a dim view of mockery, contending that it rests "upon a false opinion and proclaim[s] the imperfection of the mocker". He reasoned that either the object of the mockery is not ridiculous, in which case the mocker is wrong in treating it in such a way, or it is ridiculous, in which case mockery is not an effective tool for improvement. Though the mocker reveals that they recognize the imperfection, they do nothing to resolve it using good reason. Writing in his "Tractatus Politicus", Spinoza declared that mockery was a form of hatred and sadness "which can never be converted into joy". Catholic Bishop Francis de Sales, in his 1877 "Introduction to the Devout Life", decried mockery as a sin:  Alternatively, while philosophers John Locke and Anthony Ashley-Cooper, 3rd Earl of Shaftesbury agreed on the importance of critical inquiry regarding the views of authority figures, Shaftesbury saw an important role specifically for mockery in this process. Shaftesbury held that "a moderate use of mockery could correct vices," and that mockery was among the most important challenges for truth, because "if an opinion cannot stand mockery" then it similarly would be "revealed to be ridiculous". As such all serious claims of knowledge should be subjected to it. This was a view echoed by René Descartes, who saw mockery as a "trait of a good man" which "bears witness to the cheerfulness of his temper ... tranquility of his soul ... [and] the ingenuity of his mind." In philosophical argument, the appeal to ridicule (also called appeal to mockery, "ab absurdo", or the horse laugh) is an informal fallacy which presents an opponent's argument as absurd, ridiculous, or humorous, and therefore not worthy of serious consideration. Appeal to ridicule is often found in the form of comparing a nuanced circumstance or argument to a laughably commonplace occurrence or to some other irrelevancy on the basis of comedic timing, wordplay, or making an opponent and their argument the object of a joke. This is a rhetorical tactic that mocks an opponent's argument or standpoint, attempting to inspire an emotional reaction (making it a type of appeal to emotion) in the audience and to highlight any counter-intuitive aspects of that argument, making it appear foolish and contrary to common sense.