T ÉCNICAS DE V ALIDACIÓN DE R EQUISITOS

Though Spinoza is not a rigid apriorist, he does nevertheless maintain that all truths are in principle demonstrable, even though this may not be achievable in practice. For Spinoza 'all things have been determined by the necessity of the divine nature to exist and produce an effect in a certain way' ( Ethics I, prop. 29). It follows that a fully adequate grasp of the divine nature would enable us to demonstrate the inevitability of everything that happens. 'I have shown more clearly than the noon light, that there is absolutely nothing in things on account of which they may be called contingent' ( G II. 74; C436).

Without delving into the metaphysical background of all this (something that will be examined in the next chapter), we will simply attempt here to trace the way in which

Spinoza's denial of contingency affects his view of philosophical method, and his account of how knowledge is to be achieved. It may seem at first sight that Spinoza's denial of

contingency is out of tune with standard ways of thinking. For many tend to think of necessity as something which is rather special, which applies only to propositions such as those of logic and mathematics, which in some sense 'must' be true, or cannot be otherwise. But in the case of everyday statements about the world like 'its raining 'in London', we take it that there is no necessity: things might, as we say, have turned out differently. (For David Hume, indeed, all matters of fact and existence have this essentially contingent character: every single thing we observe could have happened differently, and any generalization we make could break down at any moment. ⁴² ) For Spinoza, however, the fact that we regard certain events as contingent happenings is a sign of a defect in our knowledge.

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Thus if we knew the full causal background which had given rise to the present state of the weather, we would know that 'it's now raining in London' is not something that may merely happen to be true; either it has to be true (it is necessary), or else it cannot be true (it is impossible):

A thing is called contingent only because of a defect in our knowledge . . . when we can affirm nothing certainly about the necessity or impossibility of its existence, because the order of causes is hidden from us ( Ethics I, prop. 33, schol. 1). ⁴³

It follows from Spinoza's position that anyone who is in the position of entertaining some proposition as a contingent fact automatically has an inadequate perception of reality.

Suppose I believe that, as a matter of fact, the earth is flat. Then my ideas are, in Spinoza's phrase, 'mutilated and confused'; if I had a more adequate perception I would see that this proposition, when combined with others, leads to a contradiction and so cannot be true. But notice that Spinoza's strictures do not only apply to the entertaining of false propositions; they also extend to what would ordinarily be thought of as contingent truths. If I believe that the sun is, as a matter of fact, larger than the moon, but lack adequate perception of the reasons which make this proposition necessarily true, then on Spinoza's view my state of mind still involves a degree of error or falsity. Falsity can be avoided only if the mind possesses a clear awareness not just of a given truth, but of the necessity of that truth. ⁴⁴

This very austere view of what counts as true knowledge is clarified further in the course of Spinoza's account of what he calls the three 'grades of cognition' (cognitionis genera). ( Ethics II, prop. 40, schol. 2). These are often referred to as Spinoza's three grades of knowledge, but this is a misleading translation. Descartes had allowed that there were certain kinds of

cognitio ('cognition' or 'awareness') that were not entitled to the honorific label scientia-a label he reserves for properly grounded systematic knowledge. ⁴⁵ Spinoza does not make the same distinction as Descartes, but he does use cognitio to cover a wide variety of states of

awareness--the lowest variety of which is not strictly a -59-

kind of knowledge at all, since it involves falsehood. ⁴⁶ The lowest grade includes mere secondhand opinion (for example, my belief that I was born on such and such a day: G II. 10;

C13); to this is added perception arising 'from sign, e.g. from the fact that having heard or read certain words we form certain ideas of them through which we imagine the things ( G II.

122; C477). ⁴⁷

Perhaps the most important example of Spinoza's lowest level of cognition is what he calls 'cognition derived from shifting experience' (cognitio ab vaga experientia). What is

represented to us in sense-experience, says Spinoza, is 'presented to the intellect in a way that is mutilated, confused, and without order'. To many of Spinoza's readers, the

unsatisfactoriness of sensory experience as a basis for knowledge would have seemed a familiar enough theme. This talk of sensory representation as 'confused' would probably have called to mind, first, Descartes's revival of the wellknown 'argument from illusion', which makes play with cases such as that of the stick that appears bent in water, where the

information provided by the senses can be misleading ( AT VII. 438; CSM II. 296). Second, the labelling of sensory experience as vaga ('fleeting', 'inconstant') might have evoked the argument (which originated with Plato ⁴⁸ ) that claims based on the senses that count as true at a certain time, or from a certain point of view, may turn out to be false at a later date, or from a different point of view. Descartes's famous discussion of the piece of wax in the Second Meditation is an exploration of this theme: as I examine the wax my senses tell me it has a certain taste and smell and colour and shape and that it emits a certain sound; but a moment later, as I move the wax to the fire, 'the residual taste is eliminated, the smell goes away, the colour changes, the shape is lost, and if you strike it it no longer makes a sound' ( AT VII. 30;

CSM II. 20). Apart from these familiar arguments, a third and much more pervasive

reservation about sensory experience had been voiced by Descartes. Descartes maintained that even when the senses are in perfect working order, and even when the conditions of sensory observation are carefully fixed, there is still something inherently indistinct and confused about the information they provide:

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If someone says he sees colour in a body . . . this amounts to saying that he sees . . .

something there of which he is totally ignorant, or in other words, that he does not know what he is seeing . . . If he examines the nature of what is represented by the sensation of colour . . . what is represented as existing in the coloured body--he will realize that he is wholly ignorant of it ( AT VIII. 33; CSM I. 217).

For Descartes, an accurate perception of the world as it really is involves confining ourselves to the clear and distinct concepts of pure mathematics: we need to abandon descriptions of the

world in terms of sensory qualities, and substitute precise quantitative notions which capture the essence of 'extended substance' ( AT VIII. 41-2; CSM I. 224).

All of these three lines of argument may have indirectly influenced Spinoza's attitude to 'inconstant experience' (cf. G II. 82; C445), but the argument that is most characteristic of his thinking about sensory experience depends on his distinction between adequate and

inadequate perception. An adequate perception, as noted above, involves not merely a perception that something is the case, but an appreciation of the necessity for its being true.

Now clearly an isolated sensory perception will merely convey the information that something is the case; moreover, no series of such perceptions, however extended, can of itself be sufficient to establish that something must be the case (a point on which Leibniz was later to lay considerable stress; see below, p. 73). It follows that one who is in search of necessary truth must go beyond the immediate data of the senses, and attempt to discover some underlying chain of reasons or causes which will establish that a given phenomenon must of necessity come about. This is what Spinoza means when he contrasts vaga

experientia with his second grade of cognition, 'reason' (ratio). Reason takes us beyond the sphere of the temporary and the contingent to the permanent underlying reasons or caues of phenomena: 'Reason perceives things truly as they are in themselves, i.e. not as contingent but as necessary' ( Ethics II, prop. 44). In place of 'vacillating opinion', one who has attained the second grade of cognition will have a rational grasp of a stable network of causes which explain how any given phenomenon must be the way it is.

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In a graphic and celebrated phrase, Spinoza expresses this by saying that it is of the nature of reason to contemplate things sub specie eternitatis ('under the form of eternity', ibid., cor. 2 ).

Above reason, his second grade of cognition, Spinoza places a third and highest grade which he calls scientia intuitiva ('intuitive knowledge'). The term scientia is, as we have seen, used by Descartes as a label for a specially privileged kind of cognition; and Spinoza and Descartes are on common ground with respect to the need to transcend sense-experience and strive for a clear and distinct intellectual cognition. But how exactly does Spinoza's ratio differ from scientia intuitiva? The contrast between necessary and contingent propositions will not help us here, since both the second and third grades of cognition are said to involve apprehension of what is necessarily true (II, prop. 41); and both are said to conceive things sub specie eternitatis (II, prop. 44, cor. 2; V, prop. 31, schol.).

Those of Spinoza's audience who had been trained in the scholastic tradition would have been aware of a standard Aristotelian distinction between nous (generally translated 'intuition') and apodeixis (generally translated 'deduction'). Nous is, according to Aristotle, the faculty

whereby we apprehend the truth of the first principles or axioms of a demonstration;

apodeixis enables us to deduce the consequences. Spinoza's use of this fundamental contrast between what is immediately apprehended and what has to be deduced emerges in the

following illustration which he provides to explain his three grades of cognition. The example concerns the mathematical exercise of finding the 'fourth proportional': ⁴⁹ given three numbers a, b, c, we are to find the number which stands in the same ratio to c as b does to a (thus, for the sequence 2, 4, 5 the answer is 10). Spinoza lists three ways of tackling the problem. The first is to do 'what merchants do' and mechanically apply a rule of thumb (for example, 'multiply the second number by the third and divide by the first'); those who follow this procedure have been taught the rule as children but (we are to suppose) have no real

understanding of why it works. This corresponds to the lowest grade of cognition. The second way involves applying the rule, but being able to back it up with a rigorous demonstration, showing that it must work for

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any series of proportional numbers. This corresponds with ratio, the second grade of

cognition. But the person who enjoys the highest grade of cognition, scientia intuitiva, is able to see the answer at a glance. 'Thus given the numbers 1, 2 and 3 no one fails to see that the proportional number is 6--and we see this much more clearly because we derive the fourth number from the very ratio which we see at one glance obtains between the first and the second' ( G II. 122; C478). Descartes, in his own account of intuition in the Regulae, stresses the fact that it is possible to intuit a chain of connections 'in a continuous and wholly

uninterrupted sweep of thought . . . so swiftly that memory is left with practically no role to play, and I seem to intuit the whole thing practically at once' ( AT X. 387-8; CSM I. 25).

Spinoza is clearly following the central Cartesian analogy between simple vision and intellection; where something is clearly and straightforwardly presented to the mind, and contains nothing that is not clear, then the mind has the ability to 'see' the truth in a way which leaves no room for error ( G II. 24; C29). ⁵⁰

Though reason and intuitive knowledge work in different ways, they can both attain to the truth, since they both operate on the basis of what Spinoza calls 'adequate ideas'. The hallmark of falsity is, for Spinoza, inadequacy or incompleteness. Fictitious ideas, he argues in his early Treatise on the Purification of the Intellect, are never clear but always confused, and 'all confusion results from the fact that the mind knows only in part a thing that is whole' ( G II.

24; C29. CF. G II. 117; C473). On this conception of understanding--what may be called a

"holistic' conception-the search for truth is a search for an ever more complete and

allembracing set of ideas, from which, as we have seen, the necessity of all true propositions will be apparent. This does not mean that sense-experience can be ignored or dispensed with entirely (as noted above, it is important for Spinoza that his postulates should square with experience). But it does mean that the philosopher will always be required to incorporate the results of sensory experience into a wider framework. Only within that wider framework will the appearance of contingency dissolve and the necessity of the truth emerge. 'It is of the nature of reason', says Spinoza, 'to view things not as contingent but as necessary'

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( Ethics II, prop. 44). It should be clear from this that one of Spinoza's most celebrated doctrines--that the truth is selfmanifesting (the truth is index sui, its own sign, or norma sui, its own criterion ⁵¹ )--is far from being a naïve piece of optimism about the ability of the human mind to distinguish the true from the false. The adequate ideas of reason and intuitive knowledge presuppose a coherent and all-embracing structure that is wholly absent in the deliverances of 'fleeting experience'. It is because of this that Spinoza is able to claim that 'he who has a true idea at the same time knows that he has a true idea and cannot doubt the truth of the thing' (II, prop. 43). Many critics asked Descartes how one could be sure that one's ideas were clear and distinct; and Descartes's answers were not always convincing (cf. AT VII.

146; CSM II. 104). Since Spinoza defined falsity in terms of failure to have an adequate perception of why a proposition must be true (or why it cannot be true), one can see why he thought that falsity must reveal itself without difficulty to a reflective intellect. Similarly, given the holistic and necessitarian character of Spinoza's account of knowledge, it is possible

to see how he came to maintain that one cannot arrive at an adequate perception without knowing one has arrived: 'As the light makes both itself and the darkness plain, so truth is the standard both of itself and of the false (II, prop. 43, schol.).