Charles asked:
Why did Kant say Hume woke him up from his dogmatic slumber? How did he address the challenge Hume posed in respect of the problem of causality? In what sense does this response constitute a basis for Kant’s metaphysics?
Answer by Martin Jenkins
Hume
After his reading of David Hume, the problems raised by the latter’s Empiricism found a resonance in Kant.
Issues such as causality, necessary connection, personal identity were explored by Hume. In his ‘Inquiry Concerning Human Understanding’, Hume had concluded that Causality is not a definite, determinate event observed by the senses, it was the constant conjunction of two events enforced by custom and habit. The latter was found to be the basis of so called necessary connection. That a thrown stone may break glass, that the sun will rise tomorrow, that in the morning, the world will appear the same way it was on the previous night do not demonstrate any necessity. As such it is perfectly reasonable that what has always been in the past, may not be so in the future…
Regarding personal identity or the self, this too cannot be perceived. There are at most an association of ideas. Mustn’t there be some thing which associates the ideas, a ‘self’. Hume contends that the ‘self’ is itself, never encountered.
Transcendental Idealism
For Kant, the epistemological issues raised by Hume posed the question of the certainty of human knowledge. It seemed that Empiricism could not provide any certainty and left matters open to scepticism.
Kant’s response was to examine human experience and deduce that there were indeed, structures common to and which mediated human experience. As you mention, causality is one such structure. We do indeed perceive objects displaying succession in Time and in Space. The structures themselves are not experienced but are the very conditions of the possibility of human knowledge.
The structures or Transcendental Categories are a-priori inherent to the human intellect. They synthesise with intuitions gained through the senses to create synthetic a-priori judgements and consequently, knowledge. Accompanying this process is the Ego with its Synthetic Unity of Transcendental Apperception. Kant expounds how this happens in his Critique of Pure Reason (1781/7). The Transcendental Categories furnish apodeictic certainty thereby giving human understanding an indubitable grounding.; this contrary to the fortuitous nature of empirical contingency.
So, for human beings, neither a-posterior empiricism nor the pure, a-priori reasoning characteristic of Metaphysics can provide knowledge nor, what this knowledge precisely is. Transcendental Idealism can – according to Kant.
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