The use of Kant’s critique of syllogism in argumentation

Abstract

Categorical syllogism is arguably the longest-studied form of deductive reasoning. Classical syllogistic theory was mostly focused on discovering structural nuances of syllogism and paid significantly less attention to the prospect of practical and everyday use of such reasoning in arguments. This is especially evident in the way classical syllogistics sorts syllogisms into four distinct figures, as the rules assigned to each figure tell only how to recognize each figure when it is presented and nearly nothing about when and why to use a particular figure in practice. Immanuel Kant (1724-1804) published a succinct critique of this approach, accusing it of creating false subtleties that obscure more than they clear things up. In turn, he offered his own theory that radically reduces the complexity of syllogistic rules to only two principles: the affirmative rule which states that the characteristic mark of a characteristic mark is a characteristic mark of the thing itself; and the negative rule which states that that which contradicts the characteristic mark of a thing contradicts the thing itself. Following Kant’s reduction, one can reconstruct a heuristic to help with the use of syllogisms in arguments. The two principles display important parallels with the relations of sufficient and necessary conditions, as both principles and both conditions have the same transitive property that enables them to be expressed as material implication. This shows that modes of first syllogistic figure can be used in arguments that deal with sufficient conditions being satisfied, modes of second syllogistic figure can be used in arguments that deal with necessary conditions being breached, modes of third figure can be used in arguments dealing with the absolute minimum for satisfying sufficient conditions, and ultimately, modes of fourth figure can be used in cases when one needs to argue for an alternative perspective to one of the previous figures.