A Short History of Modern Philosophy: From Descartes to Wittgenstein

by Roger Scruton

  God has ‘infinite attributes’. Extension is an attribute, since we perceive it as constituting the essence of the corporeal world: there is nothing more basic than extension to which the explanation of corporeal things could be referred. We have full (or, as Spinoza puts it, ‘adequate’) knowledge of the nature of extension through the science of geometry, and the existence of this systematic science of necessary truths is further proof that the idea of extension delivers God’s essential nature to our intellect.

  Monism

  Extension is an attribute of God, and like all the attributes of God it is infinite in quantity (which means, to put it crudely, that space has no boundaries, a proposition for which Spinoza provides an independent proof). It remains to examine what other attributes God might have. The other candidate bequeathed by Cartesian philosophy was thought, which Descartes put forward as the essential characteristic of mind. Spinoza argued that this too must be an attribute of the single divine substance, since it can be conceived in itself and there is nothing beyond itself by reference to which we must conceive or explain it. It has modifications— specific thoughts, images and agglomerations of the same—just as extension has its modifications. But in the rational explanation of these it is to thought alone that we need refer; having referred to thought, we do not need to go beyond it to some more basic attribute through which thought itself must be conceived. This explains why the properties of thought are pellucid to us (although it is clear on reflection that thought and extension are pellucid in a different way and for different reasons). Thought, therefore, is another attribute of the divine substance.

  While there are of necessity infinitely many such attributes, to finite beings only finite knowledge is available. Thus we can conceive God through the attribute of extension and through that of thought, while other manners of conception lie outside our intellectual capacity. In so far as the world is knowable to us, therefore, it consists of one thing, seen under two aspects, which correspond to its two knowable attributes. It can be seen either under the aspect of thought, in which case we call it God, or under that of extension, in which case we call it Nature. God or Nature (Deus sive Natura) is the single existing thing which exists of necessity and, being cause of itself, persists through all eternity. Thought and extension are not mere properties of God: they each constitute God’s essence, and each therefore present to the intellect a full and adequate idea of what God is.

  It is of course extremely puzzling to imagine in this way one thing with more than one essence: the concept of an ‘attribute’ only seems intelligible when construed epistemologically, as a reference to the two possible ways of knowing God; the alternative, ontological, conception, which attributes two separate essences to God, is extremely difficult to understand. But Spinoza definitely meant us to construe his theory ontologically, believing that only then will the full intellectual consequences contained in the concept of substance be understood. Only then could it be seen that the very same ontological argument that shows the existence of a substance, explains also the existence of thought and of extended matter. There ceases to be a distinction between creation and the creator, and the greatest theological problem therefore dissolves. Likewise there ceases to be a real distinction between mind and matter: so the greatest metaphysical problem also dissolves. Mind, matter, creation, creator—all these are simply names of the same eternal self-sustaining thing.

  Mind and its place in nature

  The theory of the attributes was partly intended by Spinoza to solve an outstanding question raised by Descartes’ philosophy of mind. If the mind is, or belongs to, a separate substance from that of the body, then how do mind and body interact? What mechanism can join two substances, so that changes in the one are explained by changes in the other? On Spinoza’s reading of ‘substance’ the suggestion is a nonsense, and his reading, he thought, is the only consistent one.

  Spinoza’s solution to the problem of mind and body is ingenious, although hard to understand in its entirety. The mind and the body are one and the same thing, which is conceived now under the attribute of thought, now under the attribute of extension.’ The theory of the attributes implies not only that the one substance can be known in two ways, but that the same two ways of knowing apply also to the modes of that substance. The mind is a finite mode of the infinite substance conceived as thought; the body is a finite mode of the infinite substance conceived as extension—and these two finite modes are in fact one and the same. Spinoza summarises the theory by saying that the mind is the idea of the body.

  However, when we describe a mode of thinking (an idea), we situate it in the total system of ideas (which is God, conceived under the attribute of thought). No explanation of an idea can be formulated, except in terms of other ideas. Similarly, when we describe a mode of extension, we situate it in the system of physical things, and explain it accordingly, through the attribute of extension. Mind and body are one thing; but they are conceptualised under rival and incommensurable systems. Hence, while we can assert in the abstract that they are identical, we can never explain a physical process in terms of a mental one, or a mental process in terms of a physical. This combination of doctrines has proved immensely puzzling to Spinoza’s commentators. On the one hand, he is a monist, believing that there is only one ultimate reality, of which everything is a mode; on the other hand, he admits a kind of dualism into his system, reaffirming the separateness of mind and body in the very act of denying it.

  Perhaps the best way to grasp what Spinoza is saying is through a somewhat distant analogy. When I look at a picture I see physical objects: patches of pigment smeared on a canvas. And I can describe these objects so thoroughly as to account for the entire picture. In doing so, I do not mention the other thing that I see: a stag hunt passing before a country house. This too I could describe so thoroughly as to give a complete account of the picture. But the two accounts are incommensurable: I cannot cross from one to the other in midstream, so to speak. I cannot describe the lead hound as frantically pursuing a patch of ochre, or the area of chrome yellow fused with oxydised linseed oil as resting on the huntsman’s knee. In some such way, Spinoza is saying, the complete description of the body describes the very same thing as the complete description of the mind; but to explain mental states in terms of physical causes is to cross in midstream to another and incommensurate language.

  Persons and things

  What, then, are we? To say that we are modes of the divine substance is not to say enough, for, as Spinoza realised, this does not yet grant to us our individuality. In particular, it does not settle the important question of how we can come to consider ourselves as things, even though, in the nature of the case, we cannot be substances. Thus Spinoza, having argued that there can be only one substance, attempted to reconcile this doctrine with the view that there is a potentially indefinite number of things. He did this by reversing Descartes’ argument about the wax.

  The wax, it will be remembered, seemed not to possess any essential unity or identity beyond that of the stuff out of which it was composed. It could be broken up, melted, transformed in respect of every one of its properties except those which pertained to matter as such. Its individuality counted for nothing in comparison with its constitution. By contrast, Spinoza observes, there are certain modifications of fundamental substance which have a kind of innate resistance to changes of the kind undergone by Descartes’ lump of wax. Things resist damage, fracture and so on, or perhaps, if injured, they restore themselves out of their own inherent principle of existence. They endeavour, as Spinoza puts it, to persist in their own being. This endeavour (conatus) constitutes their essence, in so far as it makes sense to attribute essence to something that has neither the completeness nor the self-sufficiency of a genuine substance.

  The obvious examples of these partial substances or individual things are organisms; and in describing their identity in terms of a conatus Spinoza was in effect reviving a concept from Aristotelian biology. Orga
nisms seem to have more conatus than inanimate things: they avoid injury, resist it, restore themselves when it is inflicted. This is why we are ready to attribute to them an individuality that we are not always willing to attribute to inanimate objects. We speak of a tree, a bird, a man; but only of a lump of wax, a heap of snow, a pool of water; thus identifying the first as individuals, the second only as quantities of some independently describable stuff.

  In the case of persons we are also able to know this ‘conatus’ not only under the aspect of physical cohesion such as characterises all organic-life, but also under the aspect of thought. Under this aspect conatus appears as desire, or rather (since human beings have adequate knowledge of mentality) as desire accompanied by its own idea: what we might call self-conscious desire. It is this which (judged from the mental standpoint) constitutes our striving, and the satisfaction of which therefore constitutes our good.

  Knowledge

  Spinoza’s theory of knowledge is an extension and refinement of the Cartesian theory of clear and distinct perception. For every idea there is an ideatum—an object conceived under the attribute of extension which exactly corresponds to the idea in the system of the world. Every idea is ‘of’ its ideatum, and therefore every idea possesses what Spinoza calls the ‘extrinsic’ mark of truth, namely an exact and necessary correspondence to its ideatum. Error is possible, however, since many ideas fail to possess the ‘intrinsic’ mark of truth, which is present only in ‘adequate’ ideas. Although the term ‘adequate’ comes from Descartes, it effectively replaces the notion of a ‘clear and distinct perception’, as Descartes had discussed this.

  Every adequate idea is self-evident to the one who grasps it, and ‘falsity consists in privation of knowledge, resulting from inadequate or mutilated and confused ideas’. A prime example of this inadequacy is sensory perception. My image of the sun, for example, is of a small red disc resting on the horizon: and if I trusted sense-perception alone, I should be led into false conceptions, believing that the sun itself is the ideatum of this image, when in fact its ideatum is a process in me— something going on in my eye or brain.

  Knowledge gained through sense-perception is assigned, in the Ethics, to the lowest of three levels of cognition: the level that Spinoza calls imagination or opinion. Such cognition can never reach adequacy, since the ideas of imagination do not come to us in their intrinsic logical order, but in the order of our bodily processes. By the accumulation of confused ideas we can arrive at a grasp of what is common to them—a ‘universal notion’, such as we have of man, tree or dog. But these are not in themselves adequate ideas, even if they constitute the meaning of our everyday general terms.

  The second level of cognition, exemplified by science and mathematics, comes from the attempt to gain a full (adequate) conception of essences. This involves adequate ideas and ‘common notions’, since ‘those things which are common to all and which are equally in a part and in the whole can only be conceived adequately’. To return to our example: not being part of my body, the sun cannot be adequately known through modifications of my body, but only through the science— astronomy—that aims to provide an adequate idea of the heavenly bodies. This science will begin from geometry, which is the science of extension; but it will also employ such common notions as those of ‘motion and rest’.

  The third level of cognition is intuition, or scientia intuitiva. ‘This kind of cognition proceeds from an adequate idea of the formal essence of certain attributes of God to the adequate knowledge of the essence of things.’

  Spinoza seems to mean by intuition the comprehensive understanding of the truth of a proposition that is granted to the person who grasps it, together with a valid proof of it from self-evident premises, in a single mental act.

  ‘Cognition of the first kind is the only cause of falsity... while cognition of the second and third kinds is necessarily true.’ From our point of view, therefore, the truth of an idea consists in, and is understood through, its logical connection to the system of adequate ideas. The advance of knowledge consists in the replacement of confused and inadequate ideas by adequate conceptions, until, at the limit, all that we think follows inexorably from a self-evident conception of the nature of God.

  Every idea is a mental glimpse of a physical process, and conversely every physical process is no more than an extended embodiment of an idea. It follows that ‘the order and connection of ideas is the same as the order and connection of things’. This proposition encapsulates a thoroughgoing rationalism. The relation between ideas, when considered purely from the aspect of thought, is a relation of logic: one idea follows from or provides a logical ground for another. And the only way in which an idea can give a satisfactory explanation of another idea is through such logical relations. We can explain the conclusion of a proof only by showing its logical relation to the premises. And that relation is one of necessity.

  Likewise the order of things is an order which allows for explanation. In Spinoza’s view everything that happens, since it stems from the same ineluctable nature of the single divine substance, happens not by chance but by necessity. So the order of things must exhibit that necessity. We show why one event happens in nature by showing it to be a necessary consequence of all that preceded it. And the necessity here, which compels the sequence of nature, is exactly the same as the necessity explored in a mathematical proof. Indeed, if we saw all nature adequately, so that we conceived it not only under the aspect of extension but also under the aspect of thought, then it would appear to us exactly like a mathematical proof. Physical events, seen as their corresponding ideas, would be seen to follow from each other as ideas in a mathematical sequence.

  Adequate knowledge of physical things comes about because we can have ideas of what is common to all physical processes. These common notions will reflect the universal properties of extension; hence, whatever they indicate by way of logical implications will correspond accurately to reality, since nothing in the physical world will originate in those universal properties except in accordance with the logical sequences of ideas which our common notions generate. It is the mark of such adequate ideas that, as soon as presented, they are grasped and adopted with certainty, like the clear and distinct ideas of Descartes. The certainty here is nothing but the reflection of the fact that we are so constituted that we cannot think otherwise. To be differently constituted is to be possessed of a nature that does not correspond to the common notions. But, ex hypothesi, these common notions are common because they reflect what is universal and necessary in nature. It is by abstract reasoning concerning these notions that an accurate understanding of the essence of things is obtained.

  Freedom

  The theory just sketched has a powerful, and to many unacceptable, consequence. It turns out that there is as little freedom in the world of physical things as in the world of ideas: an effect follows from its cause with all the necessity of a mathematical theorem. Moreover, every human action arises out of the same unbroken chain of causal necessity as do the movements of the planets, the falling of trees, and the steady flow of rivers. Spinoza’s determinism is in fact totally rigid, and can be seen as a consequence not of some one or other dispensable metaphysical doctrine, but of the very conception of philosophy from which he began. Once we grant the conception of God as causa sui, together, with the rationalist premise that there must be an explanation of everything, we are compelled to accept the view that the explanation of every event must refer back to God. For to find an explanation is to find a cause, and the cause of anything must lie either in it or outside it. If the cause lies in it, then the thing is causa sui, and therefore is itself God and identical with the whole of things. If the cause lies outside it, then it must lie in something else which in its turn must have a cause. Suppose that some given event might have been other than it is. It could have been otherwise only if it had been preceded by a chain of causes different from those which in fact occurred; and this would have been possible only if the
first cause had itself been different. But that first cause, God, is causa sui, and therefore has all its properties by necessity. Therefore it could not be other than it is. Hence the supposition that anything might have been otherwise is absurd.

  Spinoza writes

  the order of concatenation of things is a single order, whether Nature is conceived under one or the other attribute; it follows therefore that the order of the action and passions of our body is simultaneous in nature with the order of the actions and passions of the mind... Now all these things clearly show that the decision of the mind, together with the appetite and determination of the body, are simultaneous in nature, or rather that they are one and the same thing, which, when it is considered under the attribute of thought and explained in terms of it, we call decision, and when considered under the attribute of extension, and deduced from the laws of motion and rest, we call causation.

  Thus Spinoza’s solution of the problem concerning the relation between mind and body (namely that they are simply one and the same thing), while it overcomes all the difficulties concerning interaction which had bothered the Cartesians, has the inescapable consequence that there is no human freedom. Human beings are part of Nature, and the causal order of Nature is as rigid and unbreakable as the logical order of ideas. The unfolding of events in Nature proceeds with the ineluctability of a mathematical proof pursued by an omniscient mind. What then does human freedom amount to, when the origins of every human act are contained incipiently in the primeval idea of God or Nature just as are the origins of every occurrence?

  It is in addressing himself to this question that Spinoza developed the part of his philosophy for which he has ever since been most admired, the theory of human freedom, and the associated analysis of the passions.