This interview was originally published in The Kantian Catastophe? Conversations on Finitude and the Limits of Philosophy, edited by Anthony Morgan, published by Bigg Books in 2017, and available for purchase here.
Anthony Morgan: What are the key questions Kant hopes to answer in the Critique of Pure Reason? Allais: In the first sentence of the preface to the first edition of the Critique of Pure Reason, Kant states that there are some questions that human reason is unavoidably troubled by, which are driven by the very nature of our reason itself, which we cannot dismiss or ignore, but which human reason is unable to answer. His central concern in the Critique is with such questions, which he identifies with metaphysical questions. He presents the Critique as an answer to the question of how metaphysics is possible. He wants to give an account of which metaphysical questions we are able to answer and explain how we are able to answer them, as well as to delimit which metaphysical questions we are unable to answer, to explain the role they play in our thinking. Could you say something about the specific kinds of troubling metaphysical questions Kant is concerned with? When Kant is talking about metaphysics, the key questions he has in mind are whether there is a God, whether we have free will, and whether we have an immortal soul. He takes these to be the traditional concerns of metaphysics and calls such questions transcendent metaphysics. With respect to these questions, Kant is going to argue that it is not possible for us to have knowledge of them. Crucially, this applies just as much to the claim, for example, that there is not a God – we can’t know this any more than we can know that there is a God. At the same time, Kant is going to argue that the way we think about the world when doing science unavoidably leads us to the idea of God, and that this idea plays a crucial role in our thinking. While a large part of Kant’s project is negative (arguing that knowledge of transcendent metaphysical claims is not possible), in the process of answering his question of how metaphysical knowledge is possible he develops a different kind of metaphysics, which we can call a metaphysics of experience.
Does Kant think that there a clear-cut distinction between these more traditional metaphysical questions and the questions addressed by this ‘metaphysics of experience’? Kant takes traditional metaphysics to have been concerned with a different kind of object than objects in space and time. Objects in space and time affect our senses: we can see them, touch them, smell them, manipulate them. We can therefore have empirical, or experiential knowledge of them. An immortal soul, in contrast, as a rationalist like Descartes understands it, is not a spatial object that affects our senses. It does not make sense to ask of your immortal soul: how wide exactly is it? What is its texture? What is its scent? If metaphysics concerns a different kind of object to the spatio-temporal objects that affect our senses, an obvious question arises. Since we do not know about such objects through their affecting our senses, how do we know about them? Kant takes it that metaphysics is traditionally a non-empirical, or a priori investigation of reality. A priori knowledge is knowledge we have independent of experience. Two areas of knowledge that are plausibly thought to be a priori are mathematics and logic. If we want to know how many chairs are in the next room we need to go into the room and count them, but if we want to know what 2+2 makes, we do not collect samples of two things and two things, put them together, check what result we get in each case, worry about what sample size would be relevant to the question, and then draw a tentative empirical conclusion. Rather, we seem to establish that 2+2=4 independent of any particular experience. Of course, we may need experience to acquire the concept of ‘2’ and the concept of addition, but once we have these concepts we do not need any further experience to establish that 2+2=4, and there is no experience which we would count as falsifying this claim. While very many philosophers throughout history, including in the period Kant worked (and including Kant himself) were very interested in and even engaged in empirical science, Kant thinks that when they do metaphysics they are not investigating reality empirically, but rather attempting to establish claims about the world a priori. This still seems true: most philosophers today working on metaphysics in European and North American philosophy departments do not do experiments, field work, surveys or other forms of empirical investigation.
So how do we have a priori knowledge of reality? One way in which a priori knowledge seems comprehensible is if we think about claims about what follows from the meanings of concepts. For example, we can know a priori that a triangle has three sides because this follows from what triangle means: it is part of the concept of a triangle that it has three sides. While this is a priori knowledge, it is not very interesting knowledge: it tells us only what is already contained in concepts we have. This does not tell us anything about the nature of mind-independent reality, which is what we wanted to know about. We do not just want to know what the concept of God means – we want to know if there is a God. So the question of the possibility of metaphysics is the question of how it is possible to have substantial knowledge of the nature of reality independent of experience. The technical terms in which Kant puts the question are: how is knowledge of synthetic a priori claims possible? ‘Synthetic’ refers to substantive propositions in which a claim is being made that goes beyond what is simply contained in a concept (its opposite, ‘analytic’, refers to propositions which simply unpack what is already – perhaps implicitly – thought in a concept). A priori knowledge is justified independent of experience. So the question of how synthetic a priori propositions are possible is the question of how it is possible to have substantive, non-trivial knowledge of the nature of reality independent of experience of reality – i.e., how is metaphysics possible?
And what does Kant think about the possibility of acquiring such knowledge?
Kant opens the Critique with a comparison between metaphysics, mathematics and physics; the comparison is not favourable to philosophy! He notes how much progress, and what steady progress, mathematics and physics have made, mathematics through the use of proofs and physics through the experimental method. Results are established and agreed on, and practitioners can then build on each other’s work. In metaphysics, by contrast, nothing is agreed on, and rather than building on each other’s work, each philosopher seems to start again with building their own, often completely different system.
Descartes argues that we can prove that there is a God and that reality contains two fundamentally different kinds of substances, mental substance and physical substance. Leibniz argues that fundamental reality consists of simple, indivisible soul substances. They are not able to agree on claims that can be built on, and it is not obvious how we can adjudicate between their positions: not through any empirical method (experiment, measurement, observation) and not simply by thinking about the meanings of words. Kant thinks metaphysics is simply a mess (he calls it a battlefield) and that rather than continuing to put forward metaphysical positions, we need to take a step back and ask whether and how it is even possible to have knowledge of such claims.
So he needs to establish whether and how we could establish any substantial (synthetic) claims about the nature of reality. As already mentioned, Kant is going to argue that with respect to many of the questions that traditional metaphysics has been concerned with (God, the soul, free will), it is not possible to establish any knowledge claims. Even more basic than knowledge, we cannot have what Kant calls ‘cognition’, which is not quite the same as knowledge. Cognition, for Kant, is a kind of representation of objects that succeeds both in representing objects conceptually (making claims about them), and also actually latching onto or connecting with the objects the claims are about, and thereby showing that the claims actually relate to the world. Kant thinks we cannot have cognition without somehow being able to be in contact with, or presented with, the objects of cognition. Without this, we are just spinning concepts together in a kind of game which, for all we know, does not succeed in relating to the world.
So how would this relate to a specific metaphysical question, say, the existence of God?
For Kant, there would be at least two problems related to a claim such as ‘God exists’. First, how could we justify or establish knowledge of such claims, given that our two main ways of establishing claims (empirical investigation on the one hand, and logical investigation of the meanings of concepts on the other) cannot establish such claims. But even prior to this is the question of how it would be possible for such claims to concern objects that we can be presented with, and therefore can cognize. Kant holds that one of the central problems of traditional rationalist metaphysics is that it makes claims about objects which cannot be present to us; it therefore succeeds only in creating coherent collections of conceptual claims, which are a kind of play and with respect to which we are never able to establish if the objects the concepts refer to are even really possible.
This all sounds quite abstract though, and yet these questions about God, free will, and so on are central to our lives. Does Kant think that metaphysics only operates at this level of abstraction?
It’s certainly the case that to non-philosophers, ‘metaphysics’ sounds like a very abstract and possibly other-worldly concern, far removed from everyday life. However, as I have mentioned, Kant thinks that being led to metaphysical questions is intrinsic to human reason itself, and he thinks that all humans naturally ask such questions. Further, he thinks that the very way we investigate the world in science leads us to metaphysical questions. One kind of question we ask when we investigate the world empirically is asking of something that happened what caused it to happen. What caused the bridge to collapse? Perhaps there was a flaw in one of the beams. What caused the flaw in the beam? The answer may concern the construction process and the nature of the material the beam is made from. What explains the properties of the material the beam is made from? Perhaps we will say something about the chemical composition. What explains the chemical composition? Perhaps we will say something about the molecular bonding. We can keep asking, with respect to each answer we get – but what caused that? What explains the properties of the molecular bonding? Asking this kind of question drives science.
Kant thinks it is also inherent to reason to ask for this kind of explanation, and never to be ultimately satisfied by an explanation which itself could be further explained. Kant has an abstract term for such answers: he says they concern something conditioned. Something conditioned is something that is dependent on something else, or caused by something else, or further explained by something else. It is never a completely self-explanatory, independent thing. Kant thinks reason is never entirely satisfied with providing something conditioned as a stopping point in asking for questions about what caused something or what explains something. Where we have a conditioned explanation – for example, one involving the molecular bonding of a structure – we will always find it reasonable to look for a further explanation. We would be very puzzled by someone who said: a molecule of water consists of two hydrogen atoms bonded to an oxygen molecule, but there is nothing further to be said about the properties of oxygen and hydrogen atoms and the way they bond. Explanation just stops here! This is just the way it is and nothing explains it or causes it. Kant thinks that reason can never accept this brute contingency as a stopping point, and, as he puts it, reason always looks for a further condition for anything conditioned. For anything dependent, caused, not logically self-explanatory, reason asks: but what caused this? What explains why this is the way it is?
And this then leads on to the idea of God?
Exactly. Because reason will not regard anything conditioned or contingent or dependent as a stopping point, it will never think we have a satisfactory end to explanation until we reach something unconditioned: something entirely independent and uncaused. Reason’s search for a condition for every conditioned therefore leads us to the idea of the unconditioned. This is an entirely natural process of thought, and Kant thinks we should not be surprised to find most humans at some time of their lives, and most human cultures, asking for a cause of the physical universe. However, the fact that this is an entirely natural process of thought, and we are naturally led to the idea of the unconditioned should not be mistaken for knowledge that there is something unconditioned. We have no justification for concluding from the fact that reason looks for a condition for every conditioned that there is a condition for every conditioned.
In the process of answering his question about the possibility of metaphysical knowledge, Kant both provides an explanation of why knowledge of traditional transcendent metaphysical claims is not possible, and also establishes another kind of metaphysics, which some commentators have called a metaphysics of experience. He argues that it is possible for us to establish some substantial a priori knowledge of reality, but this will not be knowledge of non-spatio-temporal, supersensible objects, but rather will be knowledge of the spatio-temporal world. An example of the kind of claim Kant thinks we can establish is the claim that every event has a cause. Unlike the purely conceptual claim that every effect has a cause (it is part of the meaning of an effect that it is the effect of a cause, so we can know a priori that every effect has a cause), the claim that every event has a cause cannot be shown to be true merely by investigating the meaning of the words in the claim, and it also could not be established through empirical investigation. For one thing, no empirical investigation will cover every event.
However, Kant does think that we can establish that this claim is true of the world in space and time, and he introduces a method for establishing this kind of claim: showing that it is a condition of the possibility of empirical knowledge. In other words, he thinks he can prove a priori that unless it were true that every event has a cause no empirical knowledge would be possible. Scientists, and ordinary people navigating the world, investigate what caused something to happen. This is an entirely different question from investigating whether there was a cause of something’s happening. Kant thinks that we don’t empirically investigate whether something that happened had a cause; we assume that for anything conditioned there must be something responsible for its being the way it is. We assume that there is a cause and investigate empirically what the cause was.
If we can prove that the claim that every event has a cause is a condition of empirical knowledge, then we can know that this claim is true of all the objects of which we can have empirical knowledge. Thus, we will be able to establish a substantial claim about the nature of reality. Kant thinks that this is the only kind of metaphysical knowledge that is possible for us: knowledge of the limiting framework of empirical cognition. A bit confusingly, he calls this knowledge transcendental, and calls his own investigation a transcendental investigation. Whereas transcendent metaphysics actually goes beyond the bounds of experience, and tries to answer questions about non-spatio-temporal supersensible objects, a transcendental investigation looks at the a priori limiting framework of conditions of empirical knowledge.
Surely there is a difference between establishing that a claim is true of all the objects of which we can cognize, and establishing that it is true of reality? Why should we think that we can cognize all of reality?
Yes, it’s certainly the case that even if all the events that we can cognize have causes, this does not show that every event has a cause, if it is possible for there to be events that we cannot cognize. So Kant’s answer seems to depend on limiting reality to the limits of human cognition, and what enables him to make this move is the complicated and subtle form of idealism he introduces, which he calls transcendental idealism.
What philosophers mean by idealism is the claim that objects in some domain are dependent on minds (usually human minds). So, for example, one could be a realist about properties of objects like size and shape while being an idealist about properties like colour, if you think that objects do not have colour independent of human experience but do have their shape and size independent of our perceiving them. Kant’s transcendental idealism holds that the spatio-temporal world that we cognize in science does not exist independent of the possibility of our cognizing it. It thus depends on our minds. Kant does not take this to mean that all of reality depends on our minds, or that there is no mind-independent reality. He distinguishes between the world as it is in itself, and the world of human experience (the world as it appears to us). He argues that the world as it appears to us, the world of human experience and cognition, does not reveal to us the nature of the world as it is in itself (the entirely mind-independent world), and in fact that it is impossible for us to cognize the world as it is in itself. And he argues that the world of human experience is systematically and structurally dependent on features of human minds.
The kind of metaphysics that, for Kant, turns out to be possible is a metaphysics of experience that gives us synthetic a priori claims about the spatio-temporal world. This is metaphysics: it is non-empirical, and it gives us knowledge of the necessary structure of the world. It is possible because we can establish its claims as conditions of the possibility of empirical knowledge. However, it does not give us knowledge of mind-independent reality, and the knowledge it gives us is only of the limiting structure of human cognition.
So this totally alters our entire conception of what metaphysics is?
Yes, and this is why Kant thinks that what he is doing in the Critique is revolutionary: he thinks it will entirely alter philosophy. It will show us why we should cease trying to have knowledge of transcendent metaphysical claims, as well as showing us what kind of knowledge we can try to establish. Kant famously compares his position to the Copernican revolution in astronomy which altered our view of the solar system from seeing the earth as at the centre, with the stars and sun revolving around it, to seeing the earth as just one planet going round the sun. When we look up at the night sky, or watch the sun rise and set, it seems as if the stars and sun are moving around us; Kant says that Copernicus found he had more success in explaining the movement of the heavenly bodies if he attributed this apparent movement to the observer (i.e., us on a moving planet). Similarly, Kant will attribute to the observer (the human subject or the human mind) some of what we might have thought was simply attributable to the world that we are observing. Thus, Kant’s Copernican revolution can be identified with his idealism, which attributes some structural features of the world we experience to the human mind, rather than the world as it is in itself. Kant’s Copernican revolution can also be associated with his metaphysics of experience: the idea that the way to do metaphysics is to start with investigating the conditions of human cognition, which is a shift from starting with the world to starting with the subject.
So what does metaphysics look like after this revolutionary transformation? What can it still hope to achieve? I have said that Kant opens the Critique asking whether and how metaphysics is possible, and then presents a position which enables us to establish some positive metaphysical claims about the world in space and time, and also argues that we cannot have knowledge of transcendent metaphysical objects such as God and the soul. However, it is arguable that Kant’s more fundamental aim in pursuing this investigation is the question of human freedom, and in particular the metaphysical question of freedom. We can also ask about freedom in relation to, for example, political arrangements, something on which Kant has a lot to say; the question of metaphysical freedom concerns how to reconcile the way we think about causality in the natural world, and when we do science, with our idea that our actions are up to us in a way that makes it appropriate to praise or blame us for them. Kant thinks that the way we think about ourselves as moral agents, and our recognition of moral reasons, requires that we have freedom in a strong sense. When I recognise that I ought, morally, to do something, I hold that it is possible for me to do it and not to do it; this does not seem compatible with thinking that everything that happens in space and time is a function of previous states of the universe together with the laws of nature. When I think of some past act for which I feel remorse, part of my feeling of remorse involves thinking that it was possible for me to not do the act in question. However, he thinks that the way we think about the world in science, and the metaphysics we take to be associated with science, seems to threaten the idea that we have freedom, as it suggests that everything that happens in space and time is a determined function of previous states of the universe together with the laws of nature.
But this is not something we can know to be the case, presumably? That’s right. In Kant’s account, the question of human metaphysical freedom is a transcendent metaphysical question with respect to which we cannot have knowledge. He understands metaphysical freedom as involving a causal capacity to initiate a new causal chain that is not a determined function of previous states of the universe, and he holds that it is impossible for us to have knowledge that we have such a causal capacity, and we can’t even understand what this causal capacity would be, and what would really be involved in having it. However, he thinks that his transcendental idealism establishes enough with respect to securing the freedom we need for morality. Here, it is important to keep in mind that Kant aims to show both that we cannot know that we do have freedom and that we cannot know that we do not have freedom. The latter is crucial for understanding what transcendental idealism secures for us. Kant thinks that we are able to show that science, and the metaphysics required to make sense of science, cannot rule out the possibility of human freedom. While establishing merely this negative claim with respect to freedom may seem like a weak position, and less than what we might have wanted, it is actually quite powerful. First, this is because many people agree with Kant in thinking that science and the metaphysics needed to support science seems to rule out human freedom, so showing that they do not is a significant result. Further, the result is made more significant by the way Kant thinks about freedom: that it involves a capacity to initiate causal sequences that are not a determined function of previous states of the universe. He thinks he can show that this strong conception of freedom is not ruled out by thinking of events in space and time as falling under laws of nature. And finally, his negative metaphysical result has to be taken together with the beliefs he thinks we have about our freedom when we think about morality. We do believe that we have freedom, because we recognize moral reasons, praise and blame people, and hold people responsible for their actions. What we need to establish with respect to metaphysics is to ward off a threat that science seems to pose, and we do this by showing that the way we think about the world in science and metaphysics cannot show that the causality of freedom is impossible. Since we do not have scientific and metaphysical reasons to rule freedom out, and we do already believe in it in central parts of our life as rational agents, we are entitled to continue to believe in it. Please could you say a few words on how his transcendental idealism is supposed to secure the possibility of this kind of freedom given that he also holds to the position that every event in space and time has a cause that falls under a law of nature? This is a highly controversial and debated question, and depends on the equally controversial and debated question of how to understand Kant’s transcendental idealism. In my view, points which are crucial are that transcendental idealism denies that science gives a complete account of reality, and denies that it cognizes the fundamental nature of reality. This means that explanations of events in space and time involving laws of nature never give a complete and sufficient explanation of why anything happens. It is easy to see how Kant’s rejection of transcendent metaphysics applies to rationalist metaphysics which makes claims about souls, God, monads, etc., but it may be less obvious how it is also supposed to be a critique of empiricism. The crucial point, for Kant, is to put empiricism, and science, in its proper place. Empirical science explains the world in space and time; empiricist philosophy goes beyond empirical science, in making claims about the completeness of scientific explanation. While such claims are not obviously about non-spatio-temporal, super-sensible objects, like rationalist transcendent claims they in fact go beyond the bounds of experience. And as with other transcendent metaphysical claims, we are led to them so naturally and easily that we may not notice the point at which we move from claims made within science (empirical causal explanations) to metaphysical claims made about science that neither empirical science nor logic are in a position to establish. This easy mistake is what makes us think that what we know about the world through scientific explanation shows that human metaphysical freedom is not possible; transcendental idealism enables us to avoid this transcendent metaphysical error. As I understand Kant’s position, once we take seriously the incompleteness of science we can see how every event’s having a cause that falls under a scientific law is not the same as there being only one possible future that follows from the past together with the laws of nature.
Lucy Allais is jointly appointed as professor of philosophy at the University of the Witwatersrand in her native South Africa, and Henry Allison Chair of the History of Philosophy at the University of California, San Diego. In 2015, she published her first book Manifest Reality: Kant’s Idealism and his Realism. This interview was originally published in The Kantian Catastophe? Conversations on Finitude and the Limits of Philosophy, edited by Anthony Morgan, published by Bigg Books in 2017, and available for purchase here.