Kant’s Critique of Pure Reason: The Second Analogy (On Causality)

Introduction

Perhaps the single most important thing to understand about Kant’s discussion of causality is what it does and does not attempt to prove. Kant believed that it was one of the basic, fundamental categories whereby our understanding is able to understand the world as we apprehend it. But he does not argue that the recognition of this fact allows us to determine what may or may not count as an empirical rule for determining a causal relation for any future case. When it comes to developing causal relationships, whether, as a rule, x is the cause of y, Kant recognizes that each empirically grounded relationship must be developed in an a posteriori fashion as opposed to an a priori one. At the same time, he also recognizes that it is only through the general concept of a causal relationship that we are able to make sense of the relationships between events in the world at all and even of the notion of an event itself (see B240). It is the recognition of the need for some a priori basis in order to justify the concept of a causal relationship itself that motivates his discussion.

Ultimately, what he wants to show is that the difficulties raised by Hume concerning the cause-effect relationship do not place the intelligibility of our experience beyond our grasp, but in fact show the limitations of an empiricist approach. By taking a transcendental approach to the causal relationship, that is, by beginning with the way our mind itself makes understanding possible, he attempts to show that the cause-effect relationship not only lies within the limits of our understanding because of its origin within us, but acts as a kind of rule for the understanding in its attempt to arrive at experiential knowledge.

Contents:

1. The General Orientation of the Critique to the Problems Raised by Kant’s Predecessors
2. The Cause-Effect Relationship as a Rule for the Understanding
3. Kant’s Response to Hume

The General Orientation of the Critique to the Problems Raised by Kant’s Predecessors

The general orientation of the Critique to the traditional problems of philosophy must be adequately appreciated before the strengths and weaknesses of Kant’s attempt to rehabilitate the causal reasoning can be properly appraised. This is a subject that could be covered in many pages if not volumes. But let it suffice for our purpose to say that Kant’s approach to the philosophical problems raised by Locke, Berkeley, Hume, Descartes, Leibniz, and others could be described as psychological in a certain sense: in that he is attempting to reason objectively from the way in which we understand the world to what can know about it precisely on that basis. This is why much of the Critique can be described as providing the conditions for the possibility of understanding rather than claiming to deliver Knowledge about things in themselves apart from our way of understanding the world.

The Cause-Effect Relationship as a Rule for the Understanding

Kant discusses the intelligibility of the causal relationship in the following general terms:

If, then, we experience that something happens, we in so doing always presuppose that something precedes it, on which it follows according to a rule. Otherwise I should not say of the object that it follows. For mere succession in my apprehension, if there be no rule determining the succession in relation to something that precedes, does not justify me in assuming any succession in the object. I render my subjective synthesis of apprehension objective only by reference to a rule in accordance with which the appearances in their succession, that is, as they happen, are determined by the preceding state. The experience of an event [i.e. of anything as happening] is itself possible only on this assumption.

B240

In the lines that follow in B241, Kant clarifies that the rule he has in mind is “that everything which happens has a cause.” The point Kant makes about succession is intended to show that unless some such rule is applied to the succession of events they cannot be made intelligible. It is, in other words, an argument to the effect that the structural logic of the cause-effect relationship is indispensable to our understanding of events, without which experience, as an understanding of events in the world, would not be possible.

At the risk of presenting a symbolic formula that may look scary to some readers, I would like to provide the following logical description of a causal relationship as a convenient way of grasping exactly what Kant is and is not asserting. Let E be read as “event.” Then, for any two events in causal relationship,

∃x∃y . Ex ->Ey

For any particular x and any particular y, if x is a causal event and y is another event linked by a rule, then x implies y. What is important here is that this way of framing the relationship between events is a structural one for our understanding. That is, when the mind is able to impose such a structure, the structure makes our understanding of their interrelationship possible.

Another way of putting the same point is to say that our way of grasping causal relationships is an a priori feature of our understanding that makes our understanding of the connection between events possible. This sense of an originative capacity for thinking in terms of causal relationships can be brought out by looking at the structure of the proposition itself. It makes a general claim about particular events. It does not include any substitution instances, but does describe a formal framework for determining the intelligibility of any given causal claim. “If true for any particular x or y,” the argument might run, “the causal claim is in that case justified since it shows how one event may be taken to be deducible from another.”

Kant’s Response to Hume

Kant’s affirmative attitude toward causality as a way of understanding the world naturally raises the question of how he might respond to Hume’s skepticism about causality. If the implication above is taken in the strict sense, it may be seen that it hearkens back to Hume’s way of presenting a causal argument which emphasized that the effect should be deducible from the cause. But this is of course the target of Hume’s skepticism: Hume thought that all such relationships where do to a kind of conditioned association whereby we are led to tribute a causal rule to what should be regarded as a mere expectation that an event of a particular type must follow from another.

Kant in effect turns Hume’s skepticism upside down: whereas Hume’s skepticism amounts to the claim that such an a priori a rule could never be derived from our experience and must therefore be taken as exceeding the limits of our experience, Kant finds an a priori origin of the concept within the mind itself. It is on that basis, namely its origin within the mind and not in experience, that it can be said not to exceed the limits of human understanding but to be integral to the very possibility of experience itself.

Perhaps a visual metaphor may not be unwelcome in illustrating this difference. Imagine someone stringing together a series of dots in order to make a line. Since the dots make up the line, a way of extending the line would be to add more dots. As long as the dots are connected they can be considered to be part of one internal sequence. However, anything that is not a dot (or point), but has a different kind of nature, cannot be connected with the line since it cannot belong to the sequence. Transcendental concepts, such as the cause-and-effect relationship, in effect function like points that may belong to a series of dots and become part of a line rather than something that cannot belong to the sequence.

But what is distinctive about the way in which Transcendental concepts function in relation to other “points” in our experience to which they may be connected is that they are originative with respect to the possibility of the formation of further dots on the line. There must be some “first point“ in order to initiate the series, that makes the series itself possible and makes further additions to it possible. Nevertheless, transcendental concepts have a quasi-ideal character in the following way: while they are not themselves objects of experience, they are general concepts costitutive of the very possibility of experience in the broader sense of the term, which includes the possibility of understanding.

This illustration mirrors the way in which our capacity to understand the world in terms of cause-and-effect relationships becomes possible for us. In a sense, points make a line possible by acting as there inherent constituent of principle. It, in effect, explains the appearance of a whole line of cause-and-effect relationships as cause-and-effect relationships without which their appearance as such would not be possible.

But Kant does not simply dismiss Hume’s arguments. Like Hume, Kant also recognizes a gap between the de facto a priori status of causality prior to Hume’s radical empirical skepticism and the a posteriori project of establishing the necessity and universality of a causal relationship in any particular case.
What Kant what argue is that such a recognition is not incompatible with the claim he is actually making. The heart of this difference is that Kant is not arguing that causality is something that may be justified by our empirical experience of the world alone; rather, the very idea of causality is transcendentally grounded.

Thus, when Kant discusses the intelligibility of the causal relation itself, he also does so by denying that it can have its origin in experience:

the concept, if thus formed, would be merely empirical, and the rule which it supplies, that everything which happens has a cause, would be as contingent as the experience upon which it is based. Since the universality and necessity of the rule would not be grounded a priori, but only by induction, they would be merely fictitious and without genuinely universal validity…. We can extract clear concepts of them from experience, only because we have put them into experience.

B241

He does so in slightly different terms in transition to the transcendental deduction of the categories in B127:

David Hume recognized that…it was necessary that these concepts should have an a priori origin. But since he could not explain how it can be possible that the understanding must think concepts, which are not in themselves connected in the understanding, as being necessarily connected in the object, and since it never occurred to him that the understanding might itself, perhaps, through these concepts, be the author of the experience in which its objects are found, he was constrained to derive them from experience, namely, from a subjective necessity (that is, from custom), which arises from repeated association in experience, and which comes mistakenly to be regarded as objective. But from these premises he argued quite consistently. It is impossible, he declared, with these concepts and the principles to which they give rise, to pass beyond the limits of experience.

B127

His target is not Hume’s skepticism about being able to bridge the gap between experience and strict universality in being able to form a particular rule that conditions the succession of events; instead, his aim is to show that the origin of the concept of causality lies within us rather than outside us and taken from particular cases. His objective is not to show that the a priori origin of the concept within our understanding itself thereby validates all a posteriori causal reasoning about the succession of events, but to show that its a priori origin within us allows for the possibility of such reasoning and does not fall outside the limits of human understanding, but functions as a kind of logical directive for experience insofar as it may act as a rule to guide our understanding.