The Causal Objection and the Causal Realism

The introduction of mystical intuition is incompatible with the Kant’s most underlying assumptions of explanatory rationalism and causal realism. According to Kant’s explanatory rationalism, in order for knowledge to be possible, there must be a ground for representation to have relation to object. If the intellectual perception can represent Platonic Ideas, it cannot be a coincidence.

There must be some ground for the possibility of representing reality. According to Kant’s causal realism, this ground should be a real one. Either one relatum causes the other relatum, or vice versa.

It cannot be the case that both relata stand in an ideal relation initiated by a common cause. In other words, the supervenience characterization of the relation of causation does not suffice.

Given his underlying assumptions, Kant’s most fundamental objection to mystical intuition is that it cannot account for the ground of the relation of mystical intuition to divine Ideas, since mystical intuition is neither causally spontaneous nor receptive. In effect, this objection is targeted not only to mystical intuition but also to anything like the perception of intellect.

In the case of sense perception, this question is easy to answer. Sense perception can represent reality precisely because sense perception is grounded in reality by being affected by the latter.

When it comes to intellectual perception, the question of grounding becomes much thornier. The friends of the perception of intellect cannot give an account of why such “eyes of mind” can represent reality as Kant requires. On some narrow notion of natural causation, the grounding simply

83 seems impossible. Since the Platonic abstract entities are causally inert, neither can they have causal efficacy nor can they receive causal efficacy. For Kant, the causal innerness of Platonic abstract entities holds only insofar as the scope of restricted to natural causation. Divine causation is immune from the restriction, and to relate Ideas with God is not historically practiced, but also philosophically tenable.

Mystical intuition or intellectual perception simply mirrors the reality without influencing reality.

Therefore, it is committed to the mirroring model of knowledge. Kant’s point is that there is simply no way of taking advantage of the mirroring model of representation without paying the price of giving an account of the ground of the representability. Kant’s criticism can be seen as against the mirroring model of knowledge, according to which the eye of mind can simply represent the world as it is. In fact, even the mirror metaphor is not proper; the mirror image is also grounded in something.¹¹⁴

Kant’s objection to mystical intuition is reminiscent of Paul Benacerraf’s celebrated causal objection to mathematical Platonism, which is a case of the general problem of integration challenge articulated by Christopher Peacock.¹¹⁵ The point of Benacerraf’s objection is that it is impossible to provide both a satisfactory epistemology and a respectable semantics for mathematical Platonism at the same time. The mathematical Platonism is successful in providing the appropriate truth conditions for mathematical sentences. However, it fails to be accommodated with a causal account of epistemology since abstract objects are causally inert and inaccessible for sense perception. If we cannot develop a satisfactory epistemology, it renders the set of abstract objects entirely mysterious.

In fact, this is not a new objection. One of the oldest and most perennial objections to Platonism is that it cannot account for how we can have access to abstract entities if abstract objects are causally inert. Normally, the epistemology of mathematical Platonism makes an appeal to some sort of perception of intellect or rational insight, which can mirror or reflect the abstract objects without bearing causal relation to them. The standard reply of mathematical Platonism to this objection is to bite the bullet by saying that our access to abstract objects does not draw on sense perception but on some sort of perception of intellect.¹¹⁶ The intellectual perception does not have to satisfy the criterion that the account of knowledge in general must be causal.

114 See Benacerraf 1973.

115 See Peacock 1999, 1-12.

116 The most celebrated defenders of this view in modern era are Descartes and Malebranche.

84 Benacerraf revives this old objection while keeping an eye on the contemporary requirement for a respectable epistemology. Obviously, Benacerraf’s objection assumes that a respectable theory of knowledge is a causal theory of knowledge. Mathematical Platonism is untenable precisely because its correspondent epistemology cannot be causal. Nowadays the causal theory of knowledge is well-motivated. On the one hand, the paradigmatic case of perceptual knowledge lends credence to it;

on the other hand, it is congenial with the naturalist approach to epistemology.

Interestingly, Kant’s objection to mystical intuition bears superficial similarity with Benacerraf’s celebrated objection to mathematical Platonism. Both of them endorse a causal theory of knowledge. Both Kant and Benacerraf agree that the representation of object presupposed by knowledge is not an epistemic luck, but an epistemic achievement. Therefore, there must be some causal track to guarantee the reliability of knowledge.¹¹⁷

Kant’s conception of causation or grounding is more general than a contemporary causal theory of knowledge would permit. The latter is committed to a physiologically casual theory of knowledge. By contrast, Kant extends it to a metaphysically causal theory of knowledge. Metaphysical causation is more permissive than physical or physiological causation. Metaphysical causation even includes, say, the creation of object by means of which intellectual intuition, which is obviously incompatible with a naturalistic approach to epistemology.

Kant is convinced that it is a presupposition of knowledge that every kind of representing relation must have a metaphysical ground. Platonism is not a respectable position insofar as it invokes God in explaining knowledge. However, Platonism is a respectable position, insofar as Platonism offers an account of the ground of the relation of representation to object. Kant’s previous objection to Platonism is not that this kind of causation or creation presupposed by intellectual intuition is illegitimate, but that it is not ours. When it comes to mystical intuition, Kant’s point is significantly different. The problem of mystical intuition lies not in that the representation of object is magical, but in that this relation is groundless: mystical intuition is incompatible neither with empirical path nor with the transcendental path.

In line with this general requirement, Kant himself provides a causal theory of a priori knowledge. As we will see in Chapter 5, in his own transcendental path Kant draws a distinctive idealistic conclusion. In short, the difference between Platonic rationalism and transcendental philosophy lies in whether to introduce a third thing, namely, God, or to change the established notion of the second thing, namely, object. Now Kant is rejecting the alternative of introducing God and his

117 Roughly speaking, the problem of the relation of representation, or cognition, to object is the presupposition of the problem of knowledge.

85 intellectual intuition and discarding the underlying realistic metaphysics. Kant discards realism for idealism for two reasons: on the one hand, we cannot produce abstract entities, since they are not ontologically inferior; on the other hand, we cannot contact them, either, since they are causally inert,

For Kant, Platonism is wildly implausible. Kant’s move is to reject Platonism at the price of reviving idealism. Since idealism is generally regarded as incompatible with naturalism, it is even worse for a naturalist.¹¹⁸ What allies Kant and the causal theorists of knowledge is not epistemic naturalism, but epistemic atheism. Although both of them are motivated by the rejection to introduce supernatural entities, epistemic atheism cannot be deflated into epistemic naturalism. Epistemic atheism is a broader view than epistemic naturalism: the former implies the latter, but not vice versa. Therefore, the difference between Benacerraf and Kant comes down to the difference in their deeper philosophical commitment. Benacerraf’s requirement of the causal account of knowledge is motivated by epistemic naturalism, whereas Kant’s demand on the ground of the relation of representation to object is guided by his explanatory rationalism.

Now the only possible way for rationalists to escape the mystical intuition is to resort to divine reliabilism. They do not have a chance, however. As we will see in next chapter, in examining the logical fanatical path, Kant mounts an array of arguments against this move for its being guilty of explanatory anti-rationalism and of epistemic theism. At a bottom level, Kant’s project against the logical fanatical path constitutes a knocking-down objection to the neglected alternative: the Cartesian epistemology.

118 For the compatibility between naturalism and Platonism see Linsky and Zalta 1995.

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