Transcendental Idealism – Lecture 4

November 2, 2012

In the last lecture on Kant’s philosophy we described it as a revolution in the history of philosophy and a complete reversal of the previous way of understanding our knowledge of the world. This revolution bears a name, and it is a name that Kant himself gave to it:  the Copernican revolution.

Hitherto it has been assumed that all our knowledge must conform to objects.  But all our attempts to extend our knowledge of objects by establishing something in regard to them a priori, by means of concepts, have, on this assumption, ended in failure.  We must therefore make trial whether we may not have more success in the tasks of metaphysics, if we suppose that objects must conform to our knowledge […]  We should then be proceeding on the lines of Copernicus’ primary hypothesis. [Bxvi]

We can understand what this revolution might mean by comparing it to what Kant believed needed to be rejected if we were to give a secure foundation to our knowledge of the world, namely dogmatic metaphysics.

It is opposed only to dogmatism, that is, to the presumption that is possible to make progress with pure knowledge, according to principles, from concepts alone (those that are philosophical), as reason has long been in the habit of doing; and that it is possible to do this without having first investigated in what way and by what right reason has come into possession of these concepts. [Bxxxv]

The test for whether metaphysics is valid or not for Kant is experience.  As he writes in the first sentences of the introduction of The Critique of Pure Reason, knowledge begins with our experience of the world, and without this limitation of experience, there would be no brake to our imaginative production of concepts [B1]. For Kant, however, this is precisely where classical, as opposed to critical philosophy, has erred. For it has believed that the principle of a philosophical method is to be determined to the extent that it rejects reality for the ethereal realm of pure ideas, which Kant rather picturesquely describes in the image of the flight of a dove and associates with the name of Plato:

The light dove, cleaving the air in her free flight, and feeling its resistance, might imagine that its flight would be still easier in empty space.  It was thus that Plato left the world of the senses, as setting too narrow limits to the understanding, and ventured out beyond it on the wings of the ideas, in the empty space of the understanding. [A5/B9].

But if our experience of the world is the test for the validity of our philosophical method, why is Kant simply not an empiricist, rather than a transcendental idealist as we described last week, and does this not contradict the meaning and import of the Copernican revolution that asserts that the world must conform to us, rather than we to the world?  The solution to this contradiction is to see that for Kant experience is not all that it seems to be. Or to put it another way, and this is perhaps the central paradox in Kant’s thought, there is more within experience than merely experience.

Kant’s proof for this is indirect. His claim is that if we simply assert that all knowledge is empirical, then we are denying any possibility of any a priori nature of own knowledge. What Kant means by the a priori is that which is independent from our knowledge of the world that is arrived at through our senses, which can be defined in contradistinction as a posteriori knowledge.  The examples of a priori knowledge that Kant gives are mathematics and physics (we shall look at the details of this argument in the next week). I know that a triangle must have three sides without having to test this empirically.  I also know that everything in nature has a cause without having to test the hypothesis experimentally.  The criterion for the difference between a priori and a posteriori knowledge is necessity and universality [B3-4]. For this reason we should not confuse what is a priori with an empirical law, for the latter rests only on observation and there is no absolute certainty that an event could be otherwise or a different theory could be used to explain its significance, whereas without the category of causality we could not make sense of the notion of ‘event’ at all; the world would be meaningless for us.

Since what is a priori cannot come from experience, since nothing from experience can happen from necessity, then it must have another source.  This other origin is the subject. Kant writes, ‘that we can know a priori of things only what we ourselves put into them’ [Bxviii]. Why, therefore, are these a priori principles not merely subjective fantasies?  Why is not Hume right to suggest that causality, for example, is merely a subjective representation that is simply the habitual way that we look at the world, and is not an a priori necessity of our knowledge of the world? Kant’s position is not that far from Hume, as Broad is right to point out, but his disagreement with Hume is that we could not choose not to look at the world in this way (Broad 1978, p.13).[1] Thus we come to a second paradox of Kant’s thought: not all that is in the subject is merely subjective.

To see why it is not merely subjective we need to clarify certain terminological distinctions.[2] When Kant speaks about the difference between appearance and thing in itself, this should not be modelled on difference between what is merely subjective on the one hand, and what is objective on the other, as we might say, for example, using that old Platonic example, that the stick appears bent in the water, but the real stick is not. This would be to distort Kant’s distinction between appearance and thing in itself in the classical distinction between appearance and essence. The difference between the classical and critical philosophy, is that the former opposes the sensible and intelligible realms, whereas the latter places the intelligible within the sensible.  To understand what Kant means by appearance is to see that the distinction between form and matter is internal to it.  It is not, as in the classical picture, that form equals essence, and appearance matter. Kant would say, on the contrary, that it is the form of appearance that is a priori and comes from the subject, whereas the matter is given by experience and is a posteriori.[3]

To confuse the form of appearance with the matter of appearance is to confuse transcendental idealism with empirical idealism and is to mistake Kant’s project with his predecessors.  For it precisely to avoid empirical idealism that Kant invents transcendental idealism.  We need to distinguish four possible positions of epistemology to be able to determine the true nature of transcendental idealism.  They are:

  1. Transcendental Realism
  2. Empirical idealism
  3. Transcendental idealism
  4. Empirical realism.

For Kant there four positions always come in pair.  Thus if you are an empirical idealist, it necessarily follows that you are an transcendental realist, and if you are empirical realist, then it also necessarily follows that you are a transcendental idealist.  How can we explain these terms in greater detail?  First of all we need to understand that the meaning of ‘real’ and ‘ideal’ change when we are describing them in a transcendental or empirical way, and much of the confusion about Kant lies in misunderstanding these subtle differences.  Following Allison, we can define ideality as being part of consciousness, and reality as being independent or outside of consciousness (Allison 2004, p.6). From an empirical standpoint, what is ideal is the private datum of the individual consciousness, whilst what is empirical is, to use Allison’s expression, ‘the intersubjective, spatiotemporal realm of the objects of human experience.’ Where we might go wrong is when we take this empirical definition and simply transpose it to the transcendental sphere.  Thus, we confuse transcendental idealism with empirical idealism. It is this confusion that might make us think that the a priori, in Kant’s sense, is merely subjective; in other words that it simply an idea in our minds.  How then can we make sense of the distinction between the ideal and the real in a transcendental manner?  What are transcendentally ideal are the a priori conditions of human empirical knowledge, and what is transcendentally real is that which is independent of these conditions; that is to say non-sensible objects. What is important to underline here is that transcendental idealism does not speak of the content of experience, but of the conditions of experiences. Its object is not what we know, but how we know.

Kant, therefore, is an empirical realist. Objects are independent of the individual consciousness but a transcendental idealist, that the form of knowledge is the condition for these objects. It is important not to confuse transcendental idealism with psychology. Psychology is an empirical science that begins with individual consciousness from which by a process of induction, like any other natural science, it arrives at universal laws.  Universal laws of nature, however, are not the same as a priori conditions of knowledge, for the former are contingent and the latter are necessary for the representation of any object. Psychology can tell us why we see this particular object in this way, or react to this situation in this way, but it cannot provide us with the description of the object in general (how every object must be formed to be a sense object, or an object of judgement), for it too must begin with this general object as a presupposition.

As we have said, it is Kant’s argument that empirical idealism always leads to transcendental realism. We have already seen this to be the case with Descartes. If I say that all I can truly know are my representations of things in my mind, then I am claiming that reality of objects is independent of my consciousness and I cannot know them.  This further entails, as we have already recognised, that only God can know the reality of things. Transcendental realism is therefore theocentric. We might, therefore, characterise Kant’s Copernican revolution as anthropocentric. All we can know is that which remains within the limits of human knowledge, what is given to us in experience, and what is ideal is merely the form of this experience whose source is the structure of human subjectivity in general.

Works Cited

Allison, H.E., 2004. Kant’s Transcendental Idealism, New Haven: Yale University Press.

Broad, C.D., 1978. Kant : an Introduction, Cambridge; New York: Cambridge University Press.

Pippin, R.B., 1982. Kant’s Theory of Form : an Essay on the Critique of Pure Reason, New Haven: Yale University Press.


[1]. He is wrong, however, to suggest that Kant has advanced no further than Hume in this problem.

[2] What follows owes much to Allison’s account in Kant’s Transcendental Idealism (Allison 2004, pp.1–35).

[3] This is why the notion of ‘form’ is central to Pippen’s understanding of Kant’s project in  Kant’s Theory of Form (Pippin 1982, pp.1–25).


Rational Theology – Lecture 3

October 12, 2012

Although in this course we are focusing on the first part of the Transcendental Doctrine of Elements, it is worth our while, especially when it comes to Kant’s critique of Descartes, to set this argument within the broader aim of the Critique of Pure Reason. One way of thinking about Kant’s work is as a critique of philosophical theology (as we can see for this reason why he rejects Descartes) We might see the aim of Kant’s critique of philosophical theology as follows: he aims to deflate the pretensions of a rational theology in order to make room for a theology that is based up morality. The first is a negative critique of religion, the second a positive one. Let us first investigate the negative critique of philosophical theology.

Like with all the other topics of the Dialectic, the source of the theological error is to treat ideas of reason as though they were objects of human intuition. Or to put it another way, the error of dialectical reasoning for Kant, is to treat a condition of human knowledge as though it were actually an object of human knowledge. The idea that is falsely transformed into an object in speculative theology for Kant is the idea of a necessary being, and it has it most classical form in the ontological argument. Kant’s critique of the ontological argument is justifiably famous, and in fact even those who disagree with the overall aim of transcendental idealism, will support Kant’s devastating demolition of perhaps the cornerstone of 18th century metaphysics (we only have to remind ourselves of the importance of this argument for Descartes’s metaphysical solution of the agreement between the subjective and objective realms of human knowledge).

Before, however, we get to Kant’s critique of the ontological argument and therefore rational theology’s pretensions to absolute knowledge, we need to inquire about the limitations of human knowledge for Kant.

For Kant, there are two sources of human knowledge, concepts and intuitions. This means that for Kant our understanding of the world cannot be limited wholly to our experience of it. This is the paradox of philosophy’s explanation of experience (this is true from Plato onwards and not just Kant): we can only explain experience by going beyond experience. Why is this so? It is because the human understanding of the world is conceptual. I do not just immediately grasp objects outside of me; rather my knowledge of them is mediated by my cognitive faculties. These Kant describes as the ‘pure categories of the understanding.’ Also for Kant, no matter what object I am experiencing, whether it is inner or outer, this object has a temporal and spatial form, which is not given by the object itself, but through my perception of it that, so to speak, clothes it in this spatial and temporal form. Space and time, for Kant belong to consciousness and not to objects themselves.

There are, however, important consequences that follow from this hypothesis that my knowledge of objects is shaped, formed and conditioned by the very mode in which I know them. It would mean that I could never know objects as they are in themselves outside of the form of human cognition. Thus Kant makes a distinction between the thing in itself and appearance, or the noumenon and the phenomenon. The philosophical problem is what is the status of this mysterious thing in itself or Noumenon?

Our error might be to think of it as a mysterious object that lies behind the appearance, in the way for example that classical metaphysics thinks of the difference between essence and appearance. As we might see, for example, in Plato’s example of the perfect from of the bed of which the bed on which you lie down on at night is merely an imperfect copy. None the less, it is clear for Kant that the thing in itself or the noumenon cannot be such a mysterious object. For an object for Kant is not something that lies outside of human knowledge, and which thereby can be contrasted to appearances; rather the object is the result of appearance being schematised by the categories of the pure understanding.

The only meaning of the thing in itself or the noumenon for Kant must be methodological; that is to say that it follows from the meaning of appearance that we posit the notion of the thing in itself and regulative, that It does not follow, however, that we can assert any knowledge of the thing in itself, except negatively; for example, the thing in itself would be outside of space and time, since the latter are forms of human intuition. In other words, the function of the idea of the thing in itself is merely to tell us what the idea of appearance must contain, but it does not inform us about the objective reality of the thing outside of human cognition.

This brings us back to philosophical or rational theology. For it is the mistake of such a rational theology to make an assertion about the existence of such things that by definition lie outside human sensible intuition. Its error, as we have already described it, is to confuse an idea, for we can all think of the formal definition of God, with an object. This error is possible, because our conceptual ordering of our intuitions certainly extends beyond them (if they did not then all we would have would be intuitions and there would be no a priori component of human knowledge), but the illusion is brought about by asserting that what extends beyond can also extend the limits of the possible objects of human knowledge. Knowledge is the unity of concepts and intuitions, and concepts by themselves only produce fictitious objects.

Kant uses the example of the sea to vividly capture the limits of human knowledge:

This domain is an island, enclosed by nature itself within unalterable limits. It is the land of truth – enchanting name – surrounded by a wide and stormy ocean, the native home of illusion, where many a fog bank and many a swiftly melting iceberg give the deceptive appearance of father shores, deluding the adventurous seafarer ever anew with empty hopes, and engaging him in enterprises which he can never abandon and yet is unable to carry to completion. [A235-6/B294-5]

We might argue, therefore, that the rational theologist has not only sailed away from the coastline, but she is unfurling her conceptual sails to head out into the open sea to be lost forever.

Rational theology hopes to prove the existence of God. It does by arguing from an idea to an object. There are three possible arguments for the existence God, Kant argues, in Western philosophy: the ontological, the cosmological and the teleological. In each case the error is to jump from mere the mere idea of necessary being to the existence of a necessary being. One cannot, however, jump from an idea to an object. On the contrary an object must be given via intuitions, which are never simply logically produced but are given through experience.

Let us take the ontological argument as our example, because Kant believes that all the arguments for the existence end with some form of the ontological argument. Also it is here that we find Kant most sustained critique of Descartes’s argument for the existence of God that is at the heart of his metaphysics. The mistake the ontological argument makes is to confuse logical possibility with real possibility. Kant writes at the end of his critique the following:

The attempt to establish the existence of a supreme being by means of the famous ontological argument of Descartes is therefore merely so much labour and effort lost; we can no more extend our stock of theoretical insight by mere ideas, than a merchant can better his position by adding a few noughts to his cash account. A602/B630.

None the less, this argument is more than merely a logical one. It marks the end of certain conception of God as a possible theoretical object. And this is because beneath Kant’s argument is a completely different metaphysics of objects.  A possible object must be a given object, and not merely a logical one. Thus all philosophical discussion of God as object must be rejected.  God becomes an idea. But the validity of all classical arguments of God rest on treating the concept as a concept of a possible object.  To show that God cannot be object is to demonstrate that all metaphysical discussion about God’s nature is useless.

This destruction of the God of rational theology, however, makes room for the God of faith. This God is not an object, but a moral idea, whose proof is its necessity for human morality, and not for the explanation of reality (an explanation that human reason does not require). Transcendental theology only goes halfway. It purifies the concept of God of any empirical content. It is only with moral theology, where the necessity of religion, to moral life is postulated, that this absence is made good. Of course, if one does not think that the idea of God is necessary to morality, then no pseudo-rationality will make this absence good either. This is the source of Nietzsche’s critique and the idea of the ‘death of God’.

Kant, however, certainly does think that the idea of God is necessary to morality, and he argues this in the postulates of pure practical reason:

By a postulate of pure practical reason, I understand a theoretical proposition which is not as such demonstrable, but which is inseparable corollary of an a priori unconditionally valid practical law (Kant 1956, p.127).

Kant means by saying that it is indemonstrable is that we should not confuse this moral necessity with any kind of theoretical necessity. The moral certainty of the idea of God is not a substitute for the theological arguments that have been eliminated in the Critique of Pure Reason, but only expresses a subjective necessity in terms of the moral order of reason. In theoretical reason, the dialectic emerges when reason demands a totality of conditions, but this would require that reason could exceed the limits of experience, which it manifestly cannot do. Moral reason, however, also seeks its own totality, but in this case it is not a totality of things, but the ‘highest good’. This is defined by Kant as the conjunction of happiness and virtue in proportion to the moral law. The question is not whether we can achieve this, but whether this idea is necessary to our own conception of ourselves as moral beings.

It is manifestly the case that in reality there is no conjunction between virtue and happiness; the rich are happy and the poor suffer. This conjunction can only be an ideal, and this is the function of religion. There is no common ground between my moral intentions and the world. I must therefore postulate an ‘author of nature’ who ensures an identity between the moral world and this world, such that the rich shall suffer and the poor will be happy. It is, to use Kant’s expression, ‘morally necessary to assume the existence of God’ (Kant 1956, p.131).

Freedom, immortality and God are the postulates of practical reason, without them Kant argues the notion of the highest good would be impossible. We should not think, however, that the postulates prove the actual existence of God. They are only immanent to morality and have no proper meaning outside of it. There is, therefore for Kant, no corresponding object or intuition to the idea of God. It is produced only from out of the moral law that resides within us.

Works Cited

Kant, I., 1956. Critique of Practical Reason, New York: Liberal Arts Press.

Kant, I., 1998. Critique of Pure Reason P. Guyer & A. W. Wood, eds., Cambridge; New York: Cambridge University Press.


Kant and his Contemporaries – Lecture 2

October 5, 2012

We have already argued that one way of thinking about Kant’s thought is as the mediation of the two competing camps of modern philosophy, rationalism and empiricism. Such mediation, however, will entirely formal and empty, if we don’t understand the particular nature of Kant’s response to both camps; that is to say what he takes and rejects from rationalism, and what he takes and rejects from empiricism. Such a selection itself would not be possible if Kant were not able to conceive of a completely different way of thinking about subjectivity that he calls transcendental idealism. So it is not just a matter of joining two opposite philosophical schools together, which would be impossible and nonsensical, but of looking of the problem they intended to answer, in an entirely different way.

What was that problem? How do we join together or bridge the subjective with the objective world. In other words how do we know that what think, see, and feels is exactly the same as what is out there. How do we know that our representations are true at all? We shall take, for reasons of brevity, Descartes and Hume as our representatives for rationalism and empiricism respectively and we shall first of all begin with Descartes.

The most important thing to emphasis in reading Descartes, as Hatfield quite rightly emphasises in his introduction to the Meditations, is that we cannot make sense of his philosophical work without acknowledging their scientific origin.(Hatfield 2003, pp.1–36) Descartes’ problem, then, was how to justify philosophically the new science of the 17th century and to do so he had to reject the traditional Aristotelian metaphysics he was taught and which was the general way in which his contemporaries thought about nature. For this reason, we too must remind ourselves, if very schematically, what this metaphysics is.

At the heart of Aristotelian metaphysics is substance. Perhaps when we ordinarily think about this word we think of matter. When I ask you ‘what is the substance of this table?’, then you might answer ‘atoms’ or some such other word. But this is not how Aristotle thought about substance (in fact he had an entirely different word for matter, which was hyle). Aristotle’s word for substance is ousisa, which means ‘being’ or ‘a being’. In other words ‘substance’ names everything that is. The question then when I ask you ‘what is the substance of this table?’, is what makes this thing a table as opposed to chair, or horse and so on. It can’t be matter, because matter doesn’t tell me why such and such a thing is what it is opposed to something else. What is, on the contrary, are individual things, such as tables, chairs and horses, and this is what Aristotle calls substances. Indeed, as he says, it is about such things that we make judgements; the table is brown, the chair is round, the horse is lame, and so on. Substance, therefore are the subjects of propositions. What something is made up of is its matter and form. The form of something tells is why it is what it is, whereas  matter is only what is formed.

Now, of course, there is a lot more detail in Aristotle’s conception of substance than this, but for our purposes this is all that we need to know at the moment. It is precisely this view, however, that is shattered by the new science. In the Aristotelian conception of the universe, since it is made up of individual substances, every substance has to have its own explanation, which makes his science extremely complex and unwieldy. Also, many of the individual predications of this science where shown through observation to be false. For example, Aristotle placed the earth at the centre of the universe and divided it into realms the mundane and the extra-mundane (basically everything on earth, and everything above the earth). The extra-mundane realm was immutable and perfect (not subject to corruption and change as in the mundane realm). This meant that everything in the universe was meant to rotate around the earth. Yet Galileo’s observation of the moons of Jupiter showed that there were rotations independent of the earth. Rather than observation describing a multi-differentiated universe, it demonstrated that that the earth was not at the centre, that there numerous planets, and that the universe followed the same laws that were few in number (three according to Descartes).[1]

Nature, therefore, was not made of infinitely many individual substances, but the one substance that Descartes postulated was made for corpuscles of matter that were infinitely divisible and whose movement and motion could be described accurately using mathematics. Thus any phenomenon we saw, such as the light of the rainbow, could be described in its own terms, as the movement and motion of such corpuscles.

At least in his physics, Descartes did not claim that this view was certain; that is to say, he put it forward as an hypothesis that worked. His defence of the new science was therefore practical. If we accept this view of nature, then we can see that we can solve the scientific problems that remained unanswerable, or had become impossibly complex in the old Aristotelian science. What he wished to achieve in his metaphysical writing, such as the Discourses and the Meditations, was a philosophical defence of this physics. How do we know (especially since the corpuscular view of nature is not something that I see through direct observation but is only a hypothesis) that the view of nature is true, that things really are what we say they are. In other words, that there really is a bridge from the subjective to the objective world?

This is where Descartes’ view of substance becomes more complex. For in fact there is not one substance but three: God, Matter and Mind. The physical hypothesis of corpuscular nature is first of all an idea and a mathematical one. Descartes’ scepticism, which everyone knows about is, is to find those ideas that we cannot doubt, but also more importantly, to separate our minds from our senses. For his argument is that we don’t understand nature first of all through our sense and then construct an idea, but our ideas is how we make sense of our senses. The idea is first. If the idea is first, then its legitimacy cannot be guaranteed by the senses that it explains. The first stage of Descartes’ method is to make us doubt the truth of our senses. This is a traditional part of philosophical scepticism and we can read the same arguments in Plato. How can I trust my senses when I know that they lie to me? How do I know that the whole of reality is not a dream? But the second stage of doubt is more interesting. For even Plato did not doubt that mathematical truths were an accurate representation of external things. But Descartes asks, how do I know that even the truths that I am certain of are really certain. For couldn’t a malicious demon simply put in my head that 2 + 2 = 4, when in fact it is 5? All I can be certain of is that if I am thinking something that it is I who am thinking it, for even I doubt that 2 + 2 = 4, then I cannot doubt that I am doubting it. Thus, as long as I remain within my inner space of my consciousness then I know what I am thinking is what I am thinking. When I think a chair I know that I am thinking a chair and so on. What I cannot know, however, is whether what I think is what the chair is in reality, or that what I think is the same as what you think. Thus we seemed trapped inside ourselves unable to get out each of us closed in our own worlds.

How does Descartes spring the trap? The answer is the malicious demon. He has to prove that this is only a thought and not a possible reality at all, and in fact the opposite is the case. This is because there is one thought which must have a reality that corresponds to it and that is the thought of God (which is the exact opposite of the malicious demon). I have the idea of God in my mind, but I cannot be the origin of that thought since I am a finite being and this is an infinite thought (not just in terms of its content, but what the thought is, its objective reality). The only origin of this thought must be God Himself who actually exists. We now see that a gap is opened up in ourselves to the outside (the outside in this case being God). This God, who is perfect and infinite and the highest reality), would not have created a universe in which there was no agreement between the material world and the inner truth of my consciousness. Thus Descartes’ argument is that the 3 laws that he discovered in his Physics are the continuous creations of God, and that God put the understanding of this laws into his mind, such that the one agrees with the other.

It might not surprise you that not every philosopher accepted this argument an one such was Hume. We might characterise Hume’s position as we don’t need to rid ourselves of scepticism in order to have a rational scientific understanding of nature and that Descartes went too far in his metaphysical speculations in order to do so. For Hume the source of all our ideas is perceptions. It is important to underline here that he doesn’t ask why that is so. He believes that it is impossible to for us to answer this question. It is precisely because Descartes thinks he can that the ends up with his unfounded metaphysical speculation. This limitation is very important for Kant, who is more Humean than he is Cartesian in this regard, and this is why he writes a critique of reason, which means nothing less than what are the necessary limits of reason, one of which would be that the only source of knowledge that we have is impressions. Perceptions themselves are divided into two: impressions and ideas. Impressions are what we might call sensations, like the colour blue that I am seeing now. Ideas are the concepts and thoughts that we have of this impressions. Ideas are only different in kind from impressions. An idea, if you like is an older impression, one that is less vivid and present than an impression. Thus, Hume would, say a blind man cannot have an idea of the colour blue because he has never seen such a colour. Simple ideas have their origin directly in impressions, but complex ones do not, because I can associated ideas in my mind without directly being present to the object, or even the object existing at all (think of the idea of the unicorn, which is made up the impression of two other objects, which are not present, the horse and horn). Hume’s question is whether there is a necessary order in my ideas as there is in my impressions (one impression comes after another one). In other words what is it that orders or groups my thought together. Why when I think of x do I also think of y?

The answer is that I associate the one with the other and there are three such principles of association: resemblance, proximity, and causality. If I see a picture of a fox, then I am likely to think of a fox, if I imagine a room in the university, then I am likely to think of a room next to it, and finally, if I think of stone dropping from someone’s hand, then I likely to think of falling to the ground. Now it is the last principle, cause and effect, which Hume thinks is central to how we think about human knowledge or understand of nature. The understanding, Hume, says is divided into two: relations of ideas and matters of fact. In the former, he is thinking of such things like logic and mathematics. For the first we do not have to go beyond the operation of ideas themselves (if you understand the one idea, then you understand why necessarily the other idea is associated with it, since if you understand bachelor you will understand why every unmarried man is one). But in ideas that are matters of fact this is not the case. Why do we believe that the sun will rise tomorrow, when we could equally believe the opposite. Hume is not arguing that we shouldn’t believe that the sun will rise (in fact he has good argument to think why we do), but there is no logical reason why we shouldn’t. The reason why we do is that we associate one idea with the other, the idea that the sun rose yesterday with the idea that the sun will rise tomorrow. We might think that we get to this second idea through an argument, where the statement ‘the sun rose yesterday’ is a premise. If it is an argument of this kind, then it could only be a relation of ideas or a matter of fact. It can’t be the first, since there is no contradiction in thinking the opposite, but it can’t be a matter of fact, because it is precisely that kind of argument I am trying to prove, so I appear to be going around in circles.

The answer must be that my conviction must have its origin elsewhere and that a belief is not the same a giving a reason or having a reason (indeed Hume will argue that our reasons have their source in our beliefs rather than the other way around). His answer is that the source of this belief is in our impressions rather than in our ideas first of all. It is because I have had the vivid experience of the sun rising again and again in the past. The belief that it will do so in the future is a habit and custom of the mind that I associated with the impression of I am having now. Thus when I see the see the dawn, whether directly or indirectly, I immediately associate it with the idea of the sun rising and I cannot help but do so because this custom or habit belongs to human nature intrinsically. A belief then is a particular vivid idea. Not as vivid as a direct sensation, but more vivid than a reason or a concept, and it is this that cause me always to associate x with y. Of course experience is open ended. It is perfectly possible that one day my belief will be disconfirmed rather than confirmed by experience.

I would say that Kant is more on Hume side than he is Descartes. In other words he takes it as given that our experience of the world is real. That we really do have sensations and that these sensations are external and not merely the product of minds. In other words, he is an empirical realist. Where he differs from Hume is that he is not convinced that causality is merely a habit of the mind. Of course this difference rest upon how one takes this ‘merely’. How necessary is a habit or custom? One might read Hume to say that it is pretty necessary. However such a necessity is only empirical and descriptive, which is how Hume limits his investigations, whereas for Kant causality is constitutive. In other words there wouldn’t be any experience whatsoever if we didn’t have this category. In other words, for Kant, if is not that we have experience x, and then experience y and then subsequently associate them in our minds through the principle of cause and effect, but that we would have any experience of x or y without it, even though, as he agrees with Hume, causality itself is not part of our actual experience. In Kant’s language, causality is a priori and synthetic. A priori, because it is not itself experiential, and synthetic, because it is actually doing some work, organising and making sense of our experience. The question, then, is what is the difference between the a priori synthetic, and a ‘custom and habit of the mind’. It is only by reading the Critique of Pure Reason that we shall discover it.

Works Cited

Hatfield, G., 2003. Routledge philosophy guidebook to Descartes and the meditations, London: Routledge.


[1] The three laws of bodily motion: What is in motion always continues to move; always moves in a straight line; a colliding body whose motion is greater will cause the motion to deflect, or if less carries that body with it. These three laws form the basis of Newton’s laws of motion.


Introduction to Kant’s Critique of Pure Reason – Lecture 1

September 30, 2012

Those who have attended my lectures in the past know that I do not go in for intellectual biography.  I am interested in Kant the philosopher, the writer, and not Kant the man.  This does not mean of course that the social situation in which Kant wrote had no significance whatsoever on what he wrote, but the twist and turns of the relation between life and writing are far more complex and intertwining than any intellectual biography with its supposedly significant events and happenings of human life, like so many birthdays and Christmases, can give. So here are the dates if anyone wants them: Kant was born  April 22, 1724, in Königsberg, Prussia (now Kalingrad in Western Russia) and died on February 12th 1804.

Even from are position of being absolute beginners we can get something from this The Critique of Pure Reason.  And that is what we should be happy with. Why do we think that philosophical works are simply vessels of information that we can dip our hands into and get what we want without really making an effort?  On the other hand, let’s not sanctify Kant too much. Let us admit that in reading the Critique the fogs of Königsberg appear to drift across our minds making everything obscure and indistinct.  Kant was a veritable machine of concepts. This means that above all he invented a whole new language. Anyone who has attempted to learn a language knows how difficult this is, because it is not merely a matter of understanding, but of putting something in an alien expression into your own words. Reading Kant could be compared with reading Chinese in this regard. One hardly knows how to advance through the strange hieroglyphs.[1]

What is it that Kant was meant to have invented, and which we shall be trying to get our heads around this lecture?  The answer to this question is transcendental idealism.[2] Now like any philosophical doctrine the best way to begin to understand it is to grasp what it is a reaction against. No philosopher writes in isolation, but always in reaction to those who have written before hand, because no problem simple falls from the heavens.  Transcendental idealism is a reaction against two kinds of philosophy of the 18th century, empiricism and rationalism (Kant himself invented these labels or at least their use). This might seem very peculiar to us, since we might think that these two kinds of philosophy are the only two ways of doing philosophy, and thus to reject both is to reject philosophy altogether.  How can there be a philosophy that is neither rational nor empirical? You can see why Kant had to invent a whole new language of philosophy to express this third alternative, which does not fit into the traditional way of talking about things, even amongst those who disagreed vehemently against one another.

We said that transcendental idealism is opposed to both rationalism and empiricism, but it would be just as well to say that it is an amalgam of both. What it is opposed to is their pure separation into two opposed spheres.  Perhaps though, and we shall see that this can only be the most preliminary and loose explanation, we can come to the first definition of transcendental idealism as a kind of rational empiricism or empiricist rationalism. We can see that this might mean by looking at some quotes from Kant, though we shall not be quoted the Critique of Pure Reason, but what is called Prolegomena to every Future Metaphysics, and which Kant wrote as a kind of guide to the much bigger and more complicated first book, but which is unfortunately not much simpler:

I openly confess that a reminder by David Hume was the very thing which many years ago first interrupted my dogmatic slumber and gave my investigations in the field of speculative philosophy quite a new direction.[…] If we start from a well-founded though undeveloped thought which another has bequeathed to us, we may well hope by continued reflection to advance farther than the acute man to whom we owe the first spark of light. (Kant 1988, p.159)

Let us not get lost in trying here to find out what it was that Hume reminded Kant of (we shall do that in another lecture), but simply pay attention to the rather ambiguous nature of this passage.  In one sense, Kant’s philosophy owes everything to Hume’s empirical scepticism, but in another it goes quite further than it.  In what way is transcendental idealism more than empiricism? Not an easy question, as we shall see, but let us here begin to set the ground as how it will be answered.

The question is how we can get to know something and to see how Kant gets awoken from his ‘dogmatic slumber’ we need to go back to Descartes. As you all remember, Descartes put forward the interesting idea that I could doubt the whole existence of the world, but the one thing that I could not doubt is the cogito ergo sum, for even if I doubt everything I cannot doubt the I that is doubting.  This means that everything that is contained in this I also cannot be doubted.  I can think of a cup.  I might doubt the existence of cup in the real world, it might be a figment of my imagination, but I cannot doubt the idea of the cup in my mind, for it wholly present to the thought that thinks it.  The problem for Descartes is how we get from the certainty of my inner mental world, to the uncertainty of my knowledge of the external world.  The answer is God, which is why Descartes needs the philosophical proofs of God’s existence.  If God exists, which Descartes believes can be demonstrated philosophically in the form of the ontological argument, then this God must be a just, since an unjust God would be imperfect and thus contradicts His essence.  A just God ensures that the external world, which he created, corresponds to my inner world.  Thus I can be sure that my idea of the cup, which I am entirely certain of, is the same as the actual cup which exists in the external world.

What Kant calls a ‘dogmatic slumber’ is this heady mix of theology and philosophy. Kant’s argument will be how can philosophy be certain of its knowledge of the external world, when it basis its certainty on what cannot be experienced, namely God (thus, as we shall see, it is just as important for Kant to show that there can be no proof for God’s existence, as it is for Descartes to have this proof).  It would mean that our knowledge of the cup could only be guaranteed by divine intervention, and an intervention that we ourselves could have no insight into.

The fact that theology has sneaked into philosophy tells us something has gone wrong. Theology in this form (as opposed to theology proper) is usually philosophy gone a bit mad.  This can make philosophical theology interesting, but also a little suspect in its own commitment to an immanent source of human knowledge. Thus what we need to do is go back to the relation of knowledge itself, and see what really appears there without introducing a deus ex machina, or other metaphysical hobgoblins.  First of all there is subject and there is an object that confronts this subject.  What the subject knows about this object, in one sense comes from the object itself, and in another sense comes from the subject  (when we come to look at the subject in greater detail we will need to ask who this subject is – is it me or you or something greater than both of us?).  We can say therefore that unlike Descartes and all the other metaphysical dogmatists, Kant tries to understand our world immanently, rather than appealing to something transcendent.[3]

Kant is rejecting Descartes’ transcendent argument that we can only know the object by the mediation of the divine power, but at the same time he will also reject the Humean argument that we know the object simply by ‘adding up’ our sense impressions. This is because we can make a distinction between the form of our experiences and the content of our experiences. This is why transcendental idealism cannot be understood simply as the unity of rationalism and empiricism. Let us say something briefly now about why, even though Hume awakens Kant from his ‘dogmatic slumber’, he rejects crude empiricism.

Now the content of our experience does belong to the object, and Kant will call this, perhaps slightly confusingly for our purposes, sensible intuition.  But this intuition does not merely have content but also a form, and it is this form that transcends both the individual object and the subject.  It is this transcendence that Kant is referring to in the expression ‘transcendental’. It is the proof of these forms that Kant hopes to demonstrate in The Critique of Pure Reason. They are space and time, and the categories of the understanding.  What is significant here, and we shall go both in their demonstration and description by Kant later, is that these forms of the object, which are true of every object of human experience, belong to the subject. This is why Kant’s explanation of the world is immanent, for he makes no appeal to anything that might go beyond the subject that experiences. Yet, this subject, which is the source of the form of objects, is not any subject.  It is neither you nor me, for example, but is the form of the subjectivity itself; that is to say, the form of pure thought. For this subject is nothing else than reason or rationality itself.  It is this last idea which is perhaps the most difficult to explain and to grasp, as it is to understand the heart of transcendental idealism itself.

How then the Critique of Pure Reason [hereafter CPR] organised and what is does Kant think that he is doing in it? Let us look at the content page.[4] The book is divided into two parts, the ‘Doctrine of Elements’ and the ‘Doctrine of Method’. In traditional logic books in Germany at the time, this distinction between two doctrines expressed a difference between two kinds of logic, ‘general logic’ and ‘applied logic’. With Kant, however, they had a specific meaning. In the ‘Doctrine of Elements’, he treats the a priori nature of human knowledge and what are its limits, and in the ‘Doctrine of Method’, what are the implications or consequence of this a priori knowledge and its limits and how does this method differ from other methods, such as mathematical reasoning, or other ways of doing philosophy. ‘The Doctrine of Elements’ itself is also divided into two: ‘Transcendental Aesthetic’ and ‘Transcendental Logic’, which is a division that he got from a contemporary German philosopher Baumgarten.[5] The ‘Transcendental Aesthetic’ treats human sensibility and especially the pure forms of time and space, whereas the ‘Transcendental Logic’ is a description of the pure categories of the understanding. One side, therefore, has to do with sensation or sensibility, and the other, the intellect. These for Kant are the two and the only two sources of human knowledge: intuitions and concepts. The ‘Transcendental Logic’ is then also split into two, the ‘Transcendental Analytic’ and the ‘Transcendental Dialectic’.  The first has to with the positive contribution of the pure categories of the understanding to human knowledge, and the second with the negative; that is, how the misuse of these categories leads to philosophical disputes that are never ending and thus false problems. The ‘Transcendental Analytic’ itself is then further divided into two parts, the ‘Analytic of Concepts’ and the ‘Analytic of Principle’, where the first has to do with the proof of the pure categories and their number, and the second with their empirical application. Finally, the ‘Transcendental Dialectic’ is divided into two into the ‘On the Concepts of Pure Reason’ and ‘On the Dialectical Inferences of Pure Reason’, where the latter itself is divided into three, ‘The Paralogisms of Pure Reason’, ‘The Antinomy of Pure Reason’ and ‘The Ideal of Pure Reason’, which have to do with nature of the soul, the universe and God respectively and again which are basic divisions in metaphysics and logic that Kant would know at the time. His method is both positive and negative. Negative, in that he wants to demolish the old metaphysics which he believes can no longer resist the new scepticism embodied by such philosophers like Hume, and positive, in that want to replace this old metaphysics with a new one that has a more secure founding in the necessary limits of human reason. This dual approach is what Kant means by ‘critique’, which he believed was a new method in philosophy, and is why this book is called the Critique of Pure Reason.

Works Cited

Caygill, H., 1995. A Kant Dictionary, Malden, MA: Blackwell Pub.

Kant, I., 1998. Critique of Pure Reason P. Guyer & A. W. Wood, eds., Cambridge; New York: Cambridge University Press.

Kant, I., 1988. Kant : Selections L. W. Beck, ed., New York; London: Macmillan ; Collier Macmillan.


[1] There is salvation near at hand though in A Kant Dictionary (Caygill 1995).

[2] Let us say right from the start that transcendental here has not mystical or spiritual meaning as ‘transcendental meditation’.

[3] It is important here to make a clear distinction between transcendence and transcendental in Kant’s philosophy.  Transcendence is anything that appeals to a region beyond human sensibility, and in our tradition that is usually God.  The meaning of transcendental is obviously going to be more difficult and we are only going to get to its meaning by going back to this relation between the subject and the object.

[4] See the introduction to the Cambridge edition of the CPR, which gives a good explanation of its origin and structure (Kant 1998).

[5] For many years Kant used his textbook on logic to teach metaphysics to his students, so would have been very familiar with his works. Aesthetics here must be sharply distinguished from aesthetics as the study of art, thought confusing Baumgarten was the first philosopher to use this word for precisely that purpose, and later on Kant, in the Critique of Judgment also used it in that way. In the CPR, however, the word still has its ancient Greek meaning which is ‘sensation’ in the general sense and not the specific experience of artworks.