Chapter 9 CHAPTER VIII HOW A priori knowledge is possible

Kant is widely recognized as the greatest philosopher of modern times.He lived through the Seven Years War and the French Revolution, but his career as a lecturer of philosophy in Königsberg, East Prussia, never stopped.His most outstanding contribution was the creation of what he called a "critical" philosophy, which first affirmed the fact that there are kinds of knowledge and then asked how each kind of knowledge was possible.In addition, based on the answers obtained from the discussion, many metaphysical conclusions about the nature of the universe are deduced.It is of course doubtful whether all these conclusions are valid.But Kant is certainly credited with two things: first, he saw that we have a priori knowledge that is not purely "analytical," that is to say, that not every contrary proposition is a knowledge of contradictory propositions; and, secondly, he leaves no doubt of the philosophical importance of the theory of knowledge.

Before Kant, most people had the opinion that as long as any knowledge is a priori, it must be "analytical". The meaning of the word "analytical" is best illustrated by an example.If I say, "A bald man is a man," "A floor plan is a map," "A bad poet is a poet," I am making a purely analytic judgment.Here, at least two properties are given to the said subject, one of which is used to assert the subject.Propositions of the kind mentioned above are so trivial that they are not mentioned at all in practical life unless the orator is preparing to make a sophistry.These propositions are "analytical" in that the predicate follows only by analyzing the subject.Before Kant, it was generally held that all judgments, so far as we affirm a priori, belong to this category; the predicates of all such judgments are but a part of the subject of which they assert.If this is the case, we run into a decided contradiction when we try to deny anything that can be considered a priori. The proposition "A bald man is not bald" asserts that a man is bald and denies it, and is therefore itself a contradiction.Thus, according to philosophers before Kant, the law of contradiction - which asserts that nothing can simultaneously have and not have a certain quality - is sufficient to establish the truth of all a priori knowledge.

Hume (1711-1776) was earlier than Kant. He accepted the general view on what makes knowledge a priori, and at the same time he discovered that there are many cases where the relationship was considered to be analytic. Yes, the case of causality is particularly striking.Before Hume, at least the rationalists had thought that we could logically deduce the effect from the cause if we had enough knowledge; Get it right.From this he deduces the doubtful proposition that we do not know a priori what is involved in the question of causality.Kant, having been educated in the rationalist tradition, was rather disturbed by Hume's skepticism and tried to find an answer to it.Later he realized that not only causality, but also all arithmetical and geometrical propositions are "synthetic", that is to say, not analytic.All these propositions do not reveal the predicate in any analysis of the subject. The proposition 7+5=12 is his ready-made example.He quite rightly points out that 7 and 5 must be put together to get 12. The idea of ​​12 is not implied in 7 and 5, nor even in the idea of ​​adding them together.Thus he came to the conclusion that all pure mathematics, though a priori, is synthetic; but this conclusion raised a new problem, to which he tried to find an answer.

Kant raised the interesting and difficult question "How can there be pure mathematics?" at the very beginning of his philosophy.All schools of philosophy, so long as they are not purely skeptical, are bound to find an answer to this question.The pure empiricist's answer is: Our mathematical knowledge is inductive from some special cases.We already know that this answer is inappropriate for two reasons: first, the validity of the inductive principle itself cannot be proved by induction; Propositions are evidently known with certainty by considering a single instance, and it is useless to cite other instances in which these propositions are true.Therefore, our knowledge of general propositions in mathematics (as well as in logic) must be explained in other ways than in terms of (merely probabilistic) empirical generalizations such as "all men are mortal". knowledge to explain.

The problem arises because such knowledge is universal, while all experience is particular.Obviously it seems extraordinary that we should be able to know in advance the truth of particular things which we have not experienced; but the applicability of logic and mathematics to such things is not easily doubted.We do not know who will be the inhabitants of London a hundred years from now; but we do know that any two of them plus two others make a total of four.This apparent talent for predicting things we have never experienced is truly astonishing.Kant's answer to this question, though invalid in my opinion, is interesting after all.However, this answer is difficult, and various philosophers have understood it differently.We can therefore only present its simplest outline; even so, I am afraid that many representatives of the Kantian school will find this misleading.

Kant took the view that in all our experience two elements must be distinguished, one due to the object (that is, due to what we call physical objects), and the other due to our own nature. here.When discussing matter and sense data, we have already understood that the physical object and its related sense data are different, and we can regard the sense data as the result of the interaction between the physical object and ourselves.So far, we agree with Kant.What is characteristic of Kant, however, is his method of distributing the proportional components of ourselves and objects separately.He held that the material supplied by the senses—colour, hardness, etc.—is due to the object, whereas what we supply is an arrangement in space and time and all the relations between the sense materials, which may be obtained by analogy Occurs because of the perception of one material as another, or in some other way.His main reason for this view is that we seem to have a priori knowledge of time, space, causality, and analogy, but not of the real stuff in sensation.He says we may be sure that everything we shall experience necessarily exhibits those characteristics which have been affirmed of it in our a priori knowledge, because these characteristics are derived from our own nature, and therefore cannot Acquiring these characteristics, nothing can enter into our experience.

Kant believed that material objects, which he called "things in themselves," were fundamentally unknowable; what could be known were the objects we encountered in experience (which he called "appearances"). "Phenomenon" is the joint product of us and the thing-in-itself, and it must have those characteristics that originate from us, so it must conform to our prior knowledge.Therefore, although this knowledge is applicable to all actual and possible experience, it cannot be assumed to apply to external experience.Thus, despite the existence of a priori knowledge, we still cannot know about things in themselves, nor about all impractical or improbable objects in experience.In this way he wanted to untangle and reconcile the rationalist versus empiricist polemic.

Besides the secondary grounds on which Kant's philosophy may be criticized, there is one major counterargument which seems to be of the utmost importance for his approach to the problem of a priori knowledge.We are sure that facts must always obey logic and arithmetic.But thinking that logic and arithmetic are imposed on us doesn't make the point.Our nature, like everything else, is a fact of the world, so there is no certainty that it is permanent.If Kant is right, it might happen that tomorrow our nature will be changed so much that 2 plus 2 will equal 5.This possibility did not seem to have occurred to him, but it completely destroyed the certainty and generality of arithmetical propositions which he was eager to prove.Of course, this possibility is inconsistent with the views of the Kantians. Kant believes that time itself is a form added to phenomena by the subject, so our real self is not in time, and there is no tomorrow.Still, he is compelled to assume that the temporal order of the phenomena is determined by the character of the thing behind them, and this is sufficient for the substance of our argument.

If some of our arithmetical beliefs are true, they must apply equally to things whether we think about them or not, as a little reflection will show.Two bodies plus two other bodies must be four bodies in total, even though the bodies are inexperienced.We assert this, of course, because it falls within what we mean when we say that 2 plus 2 equals 4.Its truth is as indubitable as the assertion that two phenomena plus the other two equal four.Thus Kant's answer unduly limits the range of a priori propositions, and besides, his attempts to show their exact reliability have failed. Leaving aside the particular doctrine advanced by Kant; it is now the most current opinion among philosophers to regard all a priori as mental in a certain sense, because it is not so much related to external facts. It is about, rather, about the way of thinking we must adopt.In the previous chapter we have mentioned three principles commonly called "laws of thinking".In the past, it was natural to name it like this.Now, however, there are solid reasons to say the name was wrong.Let us take the law of contradiction as an example.This law is usually stated in the form "Nothing can be and is not".What it expresses is the fact that nothing can have a particular quality and not have that quality at the same time.So, for example, if a tree is a beech, it cannot also be a beech; if my table is rectangular, it cannot also be non-rectangular, and so on.

The reason why it is natural to call this principle the law of thinking is that we believe in its inevitable truth by thinking rather than by observing the outside world.When we see that a tree is a beech, we don't have to look at it again to be sure that it is not a beech; just by thinking we know that it is impossible.Even so, the conclusion that the law of contradiction is a law of thought is wrong.When we believe in the law of contradiction, what we believe is not that the mind is inherently bound to believe in the law of contradiction.This belief is a consequence of the introspection of the mind, which presupposes belief in the law of contradiction.This belief in the law of contradiction is a belief in things, not just in ideas.It is not the belief that if I think a tree is a beech, I cannot at the same time think that it is not a beech; it is the belief that if a tree is a beech, it is impossible and not a beech. beech.Therefore, the law of contradiction explains things, not just thoughts.Moreover, although belief in the law of contradiction is a thought, the law of contradiction itself is not a thought, but a fact about things in the world.If all that we believe when we believe in the law of contradiction does not apply to all kinds of things in the world, then even if we force it to be true, we still cannot save the falseness of the law of contradiction.This shows that this law is not a law of thinking.

A similar argument applies to any other a priori judgment.When we judge that 2 plus 2 equals 4, we are not making a judgment about our thoughts, but about all actual or possible pairs.Of course, our minds are wired to believe that 2 plus 2 equals 4.But when we assert that 2 plus 2 equals 4, we are not primarily concerned with this fact.There is not a single fact about the nature of our minds that makes it true that 2 plus 2 equals 4.Our a priori knowledge, therefore, so long as it is not erroneous, is not only knowledge of the nature of our minds, but must also apply to all that the universe encompasses, whether mental or non-spiritual. The fact seems to be that all our a priori knowledge is concerned with entities which, precisely, do not exist, either in the world of the mind or in the world of matter.These entities may be called intangible nouns; we have such entities as properties and relations.For example, suppose I am in my room.I exist, and so does my room; but: does "in" also exist?However, the word "in" clearly has a meaning, and it points to a relationship between me and my room.This relationship is something, although we cannot say that it exists in the sense that I and my room exist. The relation "in" is something we can all think about and understand, because without understanding it we would not be able to understand the meaning of the phrase "I am in my room."Many philosophers following Kant believe that relations are acts of the mind, that things do not have relations in themselves, that relations arise because the mind brings things together in an act of thinking, and judges that these relations are what things have. This view, however, is similar to those against which Kant has been vehemently opposed.It seems that this is very clear to Yi Xiao: the truth of the proposition "I am in my room" is not produced by thought.It may be true that an earwig is in my room, even if neither I, nor the earwig, nor anyone else is aware of the truth; for the truth concerns only the earwig and the room, and does not depend on any Something else.Relationships, therefore, should be placed in a world which is neither mental nor physical, as we shall see more fully in the next chapter.This world is extremely important for philosophy, especially for some questions about prior knowledge.We will continue in the next chapter with regard to its nature and the problems connected with it which we have already discussed.