This distinction between experiential and original representations might be extended to sensibility , the faculty of intuition. Kant recognized that the human mind is affected by objects in the course of experience, resulting in empirical intuition. Is the mind also spontaneous with respect to intuitions? Kant answers in the negative, so far as the human mind is concerned. "Our mode of intuition is dependent upon the existence of the object, and is therefore possible only if the subject's faculty of intuition is affected by that object" (B72).
An intellectual intuition would be produced by the understanding itself, just as it produces concepts. Kant held that the human understanding is not original in this way, suggesting that only God or a primordial being might have this power (though whether such is the case we can never know). Nonetheless, he held that various of his predecessors claimed that human beings are capable of intellectual intuition.
At this point, we would do well to discuss Kant's own classification of his predecessors. In the concluding section of the Critique, "The History of Pure Reason," Kant divided his predecessors in to opposing camps with respect to two concerns: what is the object of knowledge? and how is knowledge attained?
With respect to the first question, the sensualists maintain that sensible objects are the real things which can be known. The hold that only sensible objects are real, while alleged objects of the understanding (e.g., Platonic forms) are fictitious. The intellectualists, on the contrary, denigrate the objects of the senses to illusion (as in Plato's analogy of the cave) while holding the only the objects of understanding are real. Kant claimed that intellectualism is tantamount to mysticism. To know an object of the understanding independently of what is given to the senses would require an intellectual intuition, which we do not have. To posit a faculty of the mind with the capability of knowing pure objects of the understanding is mysticism. It should be noted that Kant accused Berkeley of intellectualism, and therefore of mysticism.
With respect to the second question, the empiricists hold that knowledge is attained by experience, through the formation of general concepts by abstraction. Locke is the chief representative of this view. The "rationalists" were called by Kant noologists, who hold that knowledge has its origins in human reason. Leibniz was the chief representative of his school. Hume does not fit into this classification because he denied the possibility of human knowledge, and hence was a skeptic.
Kant credited his recollection of Hume as having awakened him from his dogmatic slumber. Before he absorbed Hume's lesson, Kant had been trained in the Leibnizian school, hence as a noologist. I have already stated that Leibniz's fundamental metaphysical principle was that of contradiction: any concept which contains any contradiction signifies an impossibility, whereas any concept free of contradiction signifies a possibility. Thus the principle of contradiction was the priniciple of possibility. Actuality is known through the principle of sufficient reason.
The principle of sufficient reason states that whatever is actual ,whatever exists, does so by virtue of a reason why it exists rather than not. Human reason can gain knowledge of what is actual by appeal to the principle of sufficient reason; that is, if it is known that there is a reason sufficient for the thing, then it is known that the thing exists. In Leibniz's system, we know that God has a sufficient to create the best possible world, so we know that the best possible world exists.
Hume recognized that the principle of sufficient reason, if true at all, is a necessary truth. He then inquired as to the justification of such a principle. If it is necessarily true, then its opposite is impossible, and therefore its falsehood is unthinkable. But he held that we can always think the possibility that A exists without B, despite the belief that A is a sufficient reason for B. To be necessary, the principle of sufficient reason would have to be provable from the law of contradiction, but it cannot be. (Wolff and his followers, however, did try to derive the principle of sufficient reason from the principle of contradiction, though Leibniz did not.)
(For a short discussion of this topic, taken from the Kant List-Server, click here.)
As was stated in the lecture of January 11 , Kant held that sensibility and understanding each make their own contributions to human knowledge: intuition and concept, respectively. The two come together in the judgment, where they are connected by the copula 'is.' When I assert that the table is extended, I bring my representation of a single thing, the table, under a general concept, that of extension. (Other judgments bring concepts together, as in "All bodies are extended.")
Kant posed two fundamental questions regarding any judgment: what is its basis? and what is the relation between its elements? In keeping with distinctions we have made earlier, we can readily identify one basis of judgment: experience. On the basis of my 17+ years of living in California, I judge that California generally has good weather.
Is there another basis for judgments, besides experience? And if so, what could it be? Kant answers the first question in the affirmative, by noting that empirical judgments are one and all contingent and only relatively universal. Whatever I judge to be the case on the basis of experience, I recognize might not be the case. Things might have been otherwise than what they are: California might have generally bad weather. Empirical judgments are sometimes called judgments a posteriori.
So whatever is judged with necessity has a basis other than experience. Further, what I judge empirically is not strictly universal, that is, there is always the possibility of exception. Kant took it as established by Hume that experience can never use induction to rule out an exception. No matter how many cases have been observed, still others are possible, and they might be different from what has been observed. Thus, Kant claimed that the two criteria of a judgment not based on experience are necessity and strict universality. Such judgments are a priori, or independent of experience.
(Critics have questioned Kant's claim that the two criteria are separate. As Patrick Findler pointed out in class, the definition of strict universality appeals to the impossibility of an exception. So one could say that a strictly universal judgment is necessary.)
Kant asserted that mathematical judgments are a priori, in that they are taken to be necessary. It is never possible that 1 + 1 is anything other than 2. Similarly, causal judgments are a priori, since (as Hume had observed), they imply that a necessary connection holds between the cause and the effect. Finally, metaphysical judgments (such as that God exists, or that there are simple substances) are a priori, though it will turn out that they are not justified. These judgments cannot be made on the basis of experience.
We now turn to the relation between the elements of a judgment. When one concept (the predicate) is brought under another concept (the subject) in a judgment of the form: A is B (bodies are extended), the predicate may already be thought in the subject, though not explicitly. The concept of a body contains the nothing more that the two characteristics of extension and impenetrability. Thus to say that bodies are extended is just to say that extended impenetrable things are extended. Such judgments as ˘bodies are extended÷ are called analytic. Analysis of the subject term produces the predicate.
On the other hand, in some judgments the predicate cannot be analyzed out of the subject. In this case, the judgment is synthetic. The judgment that bodies are heavy (have weight) is synthetic, because one cannot extract the concept of weight from the characteristics of being extended and being impenetrable. The first means that the body fills some space, and the second that cannot coexist with anything else in that space. Heaviness as a characteristic is nowhere to be found. This kind of judgment requires a third thing X to unite the subject and predicate. With empirical judgments, the X is experience: we feel bodies to have weight.
So at least some empirical judgments are synthetic, and it turns out that they all are. The reason is that an analytic judgment is made on the basis of analysis of concepts alone, so experience has no role to play in the judgment. These judgments must be a priori, so at least some a priori judgments are analytic. The question Kant posed (and claimed had never been posed before) is whether there are synthetic judgments a priori. That is, whether, independently of experience, we can supply the X which unites the subject and predicate in judgments when the predicate is not contained in the subject.