Kant’s Response to Hume’s Problem of Causation

When you set up your alarm at night you expect it to sound and wake you up the following morning, when you put the kettle on you expect the water to boil, and when you put the key on your car you expect the engine to start. These are just some of the many examples from our everyday lives which shows that we rely on past experiences to be repeated in the present and in the future. This is at the heart of what we call the principle of causality, which is an essential principle in which science relies. However, for Hume, “there is no evidence that the order we find there (in nature) is necessary: There is no rationale in nature to which the rational mind of man conforms. Hume was in effect driving a wedge between reason and nature”^[1] 

That is to say, as an empiricist, Hume would only accept as knowledge anything that he could perceive by the senses: he would have had to experience it. He would, therefore, claim that there is no possibility of knowing for sure what will happen when you put the key on the ignition until you actually do it. That the fact that every time you have put the key on the ignition before it has started does not necessarily mean that it will happen this time. By claiming that, he was negating the possibility of a rational law in nature that would enable us to predict that every time A happens B will follow.

This triggered a significant amount of responses from some of his contemporaries and from many philosophers from our century who felt this matter had not been satisfactorily answered.  Whilst some of these responses have not merited much attention, Kant’s attempt to resolve Hume’s problem has been subject of many essays, studies and thesis worldwide, and it still rises the interest of incipient philosophers and diocesan seminarians. In this paper we will try then to assess the strengths and weaknesses of Kant’s solution to the problem that awoke him from his “dogmatic slumber”.

One of the strengths of Kant’s response to Hume is being able to identify better the core of Hume’s problem. Unlike some of his contemporaries, who despised Hume’s scepticism on the grounds of common sense - “such as Thomas Reid, James Oswald, James Beattie, and Joseph Priestley”^[2]-, Kant understood that Hume’s scepticism was deeper.  As Diana Mertz Hsieh^[3]  points out on her article “Hume the Cause, Kant the effect”:

“Kant aims to set the record straight: Hume never questioned that “the concept of cause was right, useful, and even indispensable for our knowledge of nature,” but instead denied that causality “could be thought of by reason a priori, and consequently whether it possessed an inner truth, independent of all experience, implying a more widely extended usefulness, not limited merely to objects of experience”^[4]

This vision of the problem posed by Hume, however, was not entirely unbiased. For anyway who have read the famous cry “Sapere Aude!” (Dare to know) in his “What is Enlightenment? “it would hardly be a surprise that “Kant was deeply committed to the Enlightenment ideal”^[5] and therefore “was deeply disturbed by Hume’s argument”^[6]. In his attempt to save the Enlightenment, he needed to save science and, given the ability it provides to explain and predict, the most essential principle it relies upon: the principle of causality.  As Diana Mertz continues, “While Kant is certainly correct that Hume never doubted the usefulness of the principle of cause and effect, his own summary of Hume’s scepticism leaves much to be desired”^[7]. Why does she say that?  Because for her: