The Oxford Companion to Philosophy Part 67 pps

natural. Belonging to or concerned with the world of *nature, and so accessible to investigation by the natural sciences. ‘Natural’ may be contrasted with various terms, such as ‘artificial’, ‘unnatural’, ‘supernatural’, ‘non-natural’. The first three of these occur in ordinary language, though ‘unnatural’ in particular leads to problems about its real meaning. But ‘non-natural’ is a philosopher’s term, and (with ‘non-naturalistic’) is the usual contrast term to ‘natural’ or ‘naturalistic’ in philosophy. Roughly it refers to what cannot be studied by the methods of the natural sciences, or defined in terms appropriate to them, and is applied to subject-matters that are essentially abstract, or outside space and time. A famous use of it was made by G. E. Moore, who applied it to the term good, which he regarded as indefinable. a.r.l. *naturalistic fallacy; naturalism. G. E. Moore, Principia Ethica (Cambridge, 1903), sects. 5–14, ‘Nat- ural’ and ‘Non-natural’. natural aristocracy: see aristocracy, natural. natural deduction. A method of formalizing logic, intro- duced independently by S. Jas´kowski in 1934 and Gerhard Gentzen in 1935. All previous mathematical logicians— including Frege, Russell and Whitehead, Hilbert, and Heyting (*intuitionism, mathematical)—had formalized logic axiomatically, their method being modelled on the misleading analogy of formal *theories. In these formaliza- tions, certain logically valid formulae were assumed as axioms, from which a minimum of rules of derivation pre- serving logical validity yielded the rest. This older method required ad hoc definitions of derivability from a set of pre- misses (since not all rules of derivation preserved truth under a given interpretation of the schematic letters); it often demanded much ingenuity to obtain the formal *theorems. Worse, it concentrated philosophical and logical attention on the notion of *logical truth in place of that of logical consequence. By contrast, a natural *deduction system has no *axioms, but only rules of *inference, thus placing the emphasis where it belongs, on the relation of logical con- sequence from premisses to conclusion, and making a for- malized deduction resemble far more closely the reasoning used in ordinary life. A formula representing one of the premisses of a deduction can be introduced at any stage; its introduction requires no justification. The price of dispensing with logical truths assumed axiomat- ically is that the rules must include some that ‘discharge’ hypotheses. One such rule is *reductio ad absurdum: under this, not-A can be asserted as following from a set Γ of pre- misses if a contradiction has been derived from Γ together with A as hypothesis; a hypothesis, like a premiss, may be introduced at any stage. The use of such rules makes it necessary to keep track of the hypotheses on which each line of a deduction depends. In order to do this, these lines may be shown as sequents—pairs Γ : Aconsisting of a finite set Γ of formulae and another formula A; the introduction of a premiss or a hypothesis is then displayed as a basic sequent of the form A : A. No formal distinction between premisses and hypotheses is needed: a premiss of the whole deduction is simply a hypothesis that is never dis- charged, but is among those on which the final conclusion depends. In a natural deduction system, the rules governing the logical *constants are divided into introduction rules and elimination rules. An introduction rule allows the deriv- ation of a formula with the given constant as principal oper- ator from premisses in which it does not occur essentially; an elimination rule allows an inference from such a for- mula, perhaps together with additional minor premisses. Thus the introduction rule for & allows the derivation of Γ : A & B from Γ : A and Γ : B and the elimination rules allow the derivation of Γ : A or of Γ :B from Γ : A & B. As this example shows, the rules are very natural and simple, and it is usually very straightforward to devise a deduction of a given conclusion from premisses from which it fol- lows. Logically valid formulae fall out as a by-product, being those formulae deducible from, or as depending on, no premisses at all. m.d. *normalization. Dag Prawitz, Natural Deduction (Stockholm, 1965). naturalism. In general the view that everything is *nat- ural, i.e. that everything there is belongs to the world of *nature, and so can be studied by the methods appropriate for studying that world, and the apparent exceptions can be somehow explained away. In central philosophy the term has been applied in two main ways, both stemming from the above definition, one more general and the other more particular. The more particular one is *ethical naturalism, which is concerned with rejecting *non-natural properties in that sphere and rejecting the idea that ethics is a sui generis sub- ject which involves special methods of argument. The more general application is to philosophy as a whole, and again involves both the objects studied and the methods used in studying them, i.e. both metaphysics and epistemology. In metaphysics naturalism is perhaps most obviously akin to *materialism, but it does not have to be materialistic. What it insists on is that the world of nature should form a single sphere without incursions from out- side by souls or spirits, divine or human, and without hav- ing to accommodate strange entities like non-natural values or substantive abstract *universals. But it need not reject the phenomena of consciousness, nor even identify them somehow with material phenomena, as the materi- alist must, provided they can be studied via the science of psychology, which can itself be integrated into the other sciences. One naturalist in fact, Hume, was rather ambiva- lent about whether there was really a material world at all, except in so far as it was constructed out of our experi- ences, or impressions and ideas, as he called them. The important thing for the naturalist in the metaphysical sphere is that the world should be a unity in the sense of 640 natural being amenable to a unified study which can be called the study of nature, though it may not always be easy to say what counts as a sufficient degree of unification. Obvi- ously there are different sciences, which to some extent employ different methods as well as studying different subject-matters. What seems to be needed is that they should form a continuous chain, and all be subject to cer- tain general requirements regarded as necessary for a sci- ence as such, like producing results which are amenable to empirical testing. Whatever entities such sciences come up with must then be allowed into the naturalistic frame- work, and these will include ‘theoretical’ entities which cannot be directly observed, but whose existence is postu- lated to explain various phenomena, such as the electrons of physics, whether this existence is taken to be real or only ‘logically constructed’ in the way in which the aver- age man is logically constructed out of ordinary men. But the main thrust of naturalism is probably best taken to be epistemological. Throughout most of the twentieth century, in particular, and for at least part of the nine- teenth, epistemology was taken to be the study of how we can properly come to have knowledge of the world around us, or indeed of anything else for that matter, the emphasis being on the ‘properly’. How people do think has been taken to be the subject of empirical psychology, and no doubt most of us think in atrocious ways at times, but that seems irrelevant to how we ought to think if we are going to find out about the world effectively. A stock question for philosophers is ‘How do you know?’, and on the face of it it can be given two kinds of answers. We might simply offer a historical or biographical account of how we came by the belief in question, or, if the ‘we’ is not an individual but a, or the, scientific community, then an account of the rele- vant part of the history of science up to the time in ques- tion. But this may seem an irrelevance. The question was not ‘Why do you believe?’ but ‘How do you know?’, and the questioner probably has in mind the further question ‘Why should I believe?’ But if so, he wants a justification for believing, and how could a mere history of somebody else’s belief give him that? Similarly, in ethics, if I ask for a justification for thinking some things to be morally wrong I shall not be very impressed if I am simply told how our moral sense grows out of childhood fears of parental authority. If anything, I might take that to undermine the belief and show it to be illusory (though it would not in fact do the latter, since there is nothing to stop us holding the right beliefs for the wrong, or even no, reasons). For this sort of reason a vigorous reaction occurred towards the end of the nineteenth century against naturalism, espe- cially in its epistemological form, often called *psycholo- gism, though to some extent in its metaphysical form too, notably in Moore’s rejection of the *‘naturalistic fallacy’ in ethics, which involved him in denying that values, and good in particular, formed a sui generis class of entities, whose presence could not be empirically observed or inferred but could only be detected by some special intuition. Logic in particular was to be purified from any contamination by psychology, and the epistemological writings of philosophers like Locke, Hume, and J. S. Mill were often regarded as asking the wrong questions. (Though it should be added that Hume himself was responsible for what has become in the twentieth century a famous attack on one form of the naturalistic fallacy, albeit a form more on the metaphysical side of the fence, since it consisted in con- necting certain ethical and metaphysical notions; Hume wanted to disconnect the ethical ones—though, some might say, only to reconnect them in a different way with certain psychological ones.) However, this purist attitude, though dominant for much of the twentieth century, has also sparked off a cer- tain reaction to itself, largely through despair. *Empiri- cism tends to move towards extremism in its attempts to beat off the ever-present challenge of the sceptic, the extremism appearing because of the concessions it is forced to make. How can we really know anything except perhaps a few things we are immediately confronted with? In particular, how can we justify the belief we all have in the ordinary world of common sense outside us? Here we return to Hume again, who in what might seem a final capitulation to the sceptic decided that we could not. What we could do, he thought, was to show that it was impossible—psychologically impossible—to take the sceptic seriously once we leave the philosopher’s study. In order to do this, starting from his extreme empiricist base, he elaborated an account of how we (or he himself—but for convenience of exposition he takes the existence of other people for granted at this point) do in fact come to think in terms of an external world. No one would com- plain at this as a programme in its own right. What is con- troversial, and is rejected by anti-naturalists, is the claim that this is all that can be done in the face of the sceptic, or, even worse, the claim that this somehow is a justification of our knowledge. The twentieth-century reaction in favour of naturalism really took the form of a repeat per- formance of Hume’s enterprise, though put in the terms of a later framework of thought. Following the title of a famous article by Quine this pro- gramme is now known as *‘naturalized epistemology’. It can take a moderate or an extreme form. The extreme, and less common, form abandons all hope of justification and in effect amounts to a philosophy of ‘anything goes’: whatever the scientists, or the astrologers, do, we must simply describe or analyse it, and leave it at that—a policy with echoes outside philosophy of science in the mid- twentieth century *linguistic philosophy ushered in by Wittgenstein. The moderate form does not abandon all hopes of justi- fication, but claims that the history of a scientific theory is not irrelevant to its justification. (Twentieth-century nat- uralism in both its forms tended to concentrate on science as the most disciplined and self-conscious area of human reasoning.) The main reason for this appeal to history is that we cannot break free from the context in which our thought arises. We must start from where we are. We may pass judgements on a theory or procedure, it is thought, but to ignore its content—what could have been naturalism 641 known at the time in question etc.—and demand some exercise in pure thought starting from nothing is to cry for the moon. The issue remains open. To what extent is it worth trying to construct a pure logic of inquiry if it could only be applied in ideal circumstances to which we can never attain? But there is in any case some connection of thought with *reliabilism, since on that view in order to decide whether a certain belief amounts to knowledge we must ask not about the reasons that the belief’s holder can produce for it but about the method by which the belief was reached, and whether that method has in fact proved to be a reliable method in other cases—in other words we must ask about the actual history of the method and about its success-rate. In aesthetics ‘naturalism’ refers not so much to an aes- thetic theory but to a movement in art associated particu- larly with the nineteenth century and related to that called realism; it claimed that art or literature should aim to rep- resent the world as it is in itself, in ways that will appeal to our aesthetic feelings or draw our attention to aspects that we might have overlooked, but without distorting it in order to produce special effects, as Turner tried to do in the case of light, or appealing to certain standard conven- tions concerning the representation of attributes, as in medieval iconography, or introducing conventions of the artist’s own, as in symbolist poetry, or in general deliber- ately representing the world otherwise than as one would normally take it to be. Naturalism in this sense is also of course to be contrasted with abstract art, as represented by, say, Mondrian. a.r.l. P. Kitcher, ‘The Naturalists Return’, Philosophical Review (1992). Fully referenced survey of current revival. T. S. Kuhn, The Structure of Scientific Revolutions (Chicago, 1962; rev. edn. 1970). Naturalistic approach. G. E. Moore, Principia Ethica (Cambridge, 1903), sects. 5–14. Challenges ethical naturalism. L. Nochlin, Realism (Harmondsworth, 1971). Naturalism in art. W. V. Quine, ‘Epistemology Naturalised’, in Ontological Relativity and Other Essays (New York, 1969). naturalism, biological: see biological naturalism. naturalism, ethical. The views that (i) ethical terms are definable in non-ethical, natural terms, (ii) ethical conclu- sions are derivable from non-ethical premisses, (iii) ethical properties are natural properties. A ‘natural’ term or prop- erty is one that can be employed or referred to in natural scientific explanations. Version (i) was attacked by G. E. Moore for committing the *naturalistic fallacy. ‘Good’ could not mean, say, ‘pleasurable’, since it is an open ques- tion whether what is pleasurable is good. Emotivists and prescriptivists object that ethical terms have non- reducible ‘attitudinal’ content. (*Descriptivism.) Version (ii) is open to Hume’s ‘is’ and ‘ought’ objection: valid ‘ought’ conclusions require an ‘ought’ in at least one pre- miss. (*Fact–value distinction.) Version (iii) is criticized by non-naturalists such as Wiggins for *scientism—the claim that genuine properties must be scientific. r.cri. *emotivism; prescriptivism. G. Harman, The Nature of Morality (Oxford, 1977), ch. 2. G. E. Moore, Principia Ethica (Cambridge, 1903), chs. 2–3. naturalistic fallacy. G. E. Moore (Principia Ethica (1903)) argued that no matter what definition of ‘good’ is pro- posed (e.g. as what satisfies desire, maximizes happiness, or furthers evolution), it can always be asked, ‘But is that good?’ The question always remains open, and never becomes trivial. ‘Good’ resists definition or analysis: and the attempt to pin it down to an invariable, specific con- tent is, in Moore’s phrase, the ‘naturalistic fallacy’. Moore was concerned to retain an objectivist position over judgements about *good. If these could not refer to natural properties (he argued), they must refer to *‘non- natural’ ones. It is questionable, however, whether object- ivism needs such a concept, and whether ‘non-natural’ can be defended from emptiness. r.w.h. *open question argument. Bernard Williams, Ethics and the Limits of Philosophy (London, 1985), ch. 7. naturalized epistemology. Whereas traditional episte- mology is concerned with analysing the concepts of knowledge, justification, etc., and with explaining what should count as good reasons for forming and retaining beliefs, proponents of naturalized epistemology think that the theory of knowledge is a branch of the scientific enter- prise. Such theorists deny that we can find a fixed point out- side science from which to scrutinize the credentials of our beliefs and the tenability of our practices of acquiring knowledge. Naturalized epistemology sees itself as con- cerned primarily with exploring the mechanisms by which perceptual information about the world is transformed into the complex edifice of scientific and everyday know- ledge. The naturalized approach to epistemology goes hand in hand with a rejection of the traditional distinction between *analytic and synthetic statements. Naturalized epistemologists tend to be externalists about justification, holding that what makes a belief justified is the overall reli- ability of the mechanisms that generated it. j.ber. *naturalism. H. Kornblith (ed.), Naturalizing Epistemology (Cambridge, Mass., 1985). natural kind: see kind, natural. natural law. Moral standards which, on a long-dominant but now disfavoured type of account of morality, political philosophy, and *law, can justify and guide political authority, make legal rules rationally binding, and shape concept-formation in even descriptive social theory. The sounder versions (e.g. of Plato, Aristotle, and Aquinas) consider morality ‘natural’ precisely because reasonable (in an understanding neither consequentialist nor Kantian). Likewise, contemporary versions plead not guilty of the ‘is–ought’ fallacy: natural law’s first (not yet 642 naturalism specifically moral) principles identify basic reasons for action, basic human goods which are-to-be (ought to be) instantiated through choice. Practical knowledge of these presupposes, but is not deduced from, an ‘is’ knowledge of possibilities; full ‘is’ knowledge of human nature is partly dependent on, not premiss for, practical (‘is-to-be’) under- standing of the flourishing (including moral reasonable- ness) of human individuals and communities. j.m.f. *good; well-being; ‘is’ and ‘ought’ Pufendorf. John Finnis (ed.), Natural Law (New York, 1993). natural or scientific laws: see natural or scientific. natural rights. Human rights, as articulated in a moral or political theory of *natural law. Of high philosophical and historical interest is the still inadequately understood lin- guistic and conceptual transformation of the Roman term ius from its primary sense (roughly, what is right, just, law- ful) to its late-medieval and modern sense: a power, lib- erty, immunity, or claim—i.e. a right (in justice or law) relationship between persons articulated precisely from the standpoint of the relationship’s beneficiary. This termino- logical specialization facilitates understanding of the wrong in abuse of one person by another: its unreason- ableness (e.g. violation of the *golden rule, or choice pre- cisely to damage a basic human good) not only deforms the agent, but also offends the victim’s fundamental equal- ity of human dignity, in a respect specified in the natural right thus violated. j.m.f. John Finnis, Natural Law and Natural Rights (Oxford, 1980). natural theology. The acquisition of truths about God through the natural human capacity to know, rather than by *revelation. The study of God through the exercise of human reason, especially as legitimated by Romans 1: 18ff. Natural theology includes the study of God through his works and the drawing of conclusions about God from premisses about creation. All putative proofs of the exist- ence and nature of God belong to natural theology. Kant and the Logical Positivists think natural theology impossible, Kant on the ground that the transcendent mis- use of the categories generates contradictions, the Logical Positivists partly on the Humean ground that there is no valid inference from empirical premisses to transcendent conclusions, but also on the ground that the sentences of theology are without meaning because in principle unveri- fiable. Aquinas takes the view that human reason provides only a limited perspective on reality, which needs to be supplemented by faith. Faith is by *grace. s.p. Aquinas, Summa Theologiae (London, 1963–75). David Hume, Dialogues Concerning Natural Religion, ed. Norman Kemp Smith (Indianapolis, 1962). Immanuel Kant’s Critique of Pure Reason, tr. Norman Kemp Smith (London, 1978). nature. As with a very large number of concepts import- ant to philosophers, ‘nature’ is a term with various mean- ings. Three seem especially worthy of note. First, by ‘nature’ we mean everything that there is in the physical world of experience, very broadly construed. The universe and its contents, in short. To be natural is to be part of this world, and its distinguishing feature is usu- ally taken to be the universal action of *laws, meaning unbroken regularities. For philosophers like Plato, as well as for those standing in the Christian tradition, the Creator necessarily exists outside his creation, although able to intervene miraculously in it. A matter of some dispute has been the question whether nature, as God’s creation, is thereby necessarily good. If this be so, how then do we account for the apparent existence of evil in the world? Well known are such saving explanations as that based on the effects of human *freedom. It is not altogether easy to maintain a reasoned belief in a dimension of existence beyond nature considered in this broad sense. Almost by definition, such a supernatural world has to be unknowable, and if (as in the Thomistic tradition) one attempts to achieve understanding through analogy, the temptation is to slide into a description of a state which seems remarkably like our own. For instance, even though God may be outside our law, does this mean that he is outside law altogether? Many have thought not, and this has proven a slippery slope, as was the case for the *Naturphilosophen, who started by seeing God’s patterns being repeated through the world, inorganic and organic, and who ended with something close to pantheism, iden- tifying God with his creation. Thomas Carlyle’s ‘natural supernaturalism’, taking the change of ice into water to be miraculous, speaks to the confusion. The second sense of ‘nature’ identifies with the living world (past and present) as opposed to the non-living. It is such a distinction that one intends when one speaks of a museum of natural history. The burning philosophical problem here is chiefly that of definition and demarcation. Today we think that the world of organisms is the product of *evolution, beginning (on our earth) almost four mil- lion years ago. Does this then mean that we can distin- guish a mammal from a lump of rock only in terms of their respective histories, or will there be essential defining characteristics of the living which set the two aside? From Aristotle on it has been argued that organisms are distinguishable from the inert world by virtue of the fact that they possess some sort of life force—most recently called the *‘entelechy’ by the vitalist Driesch. However, although it is true that organisms manage to do some remarkable things—for instance, sustaining themselves by taking in energy from the outside—it is not easy to see how an explanation of such facts as these is aided by refer- ence to unseen vital powers. Modern opinion therefore inclines to the belief that the distinguishing mark of the organic lies in its high degree of organization rather than anything physical as such. To the Darwinian, as to the natural theologian, the mark of such organization is that it sustains ‘adaptation’, whereby the features of organisms promote the survival and reproduction of their possessors. It should be noted that, although this may all be of value to the individual nature 643 organism, in a world which has produced the AIDS virus it is not immediately obvious that because something is living it thereby inherently possesses absolute value. Many—from Plato to the socio-biologist Edward O. Wilson —believe nevertheless that value does emerge from the living world, because organic organization permits an ordering according to some scale of progress. However, especially inasmuch as this progress is linked to evolution, there are as many who are adamant in their opposition. The third sense of ‘nature’ is that which sees every- thing, especially the organic world, set off against humans and the consequences of their labours. It is this sense which is being invoked when breakfast cereals are described as ‘natural’, and the real point of philosophical controversy arises over whether one should argue that it is nature in its raw pristine state which is truly good and worth while, or if one should argue that it is only inas- much as nature has been altered and cultivated by humans that true worth appears. Although the organic-food indus- try thrives on the first disjunct, there have been many ready to endorse the second. To John Stuart Mill, for instance, it was clear that ‘the very aim and object of action is to alter and improve Nature’. Perhaps the best way out of this seemingly insoluble dilemma is to recognize that, as with those who have tried to characterize *human nature, the very attempt to draw the distinction is to invite sterile disputes. Although the science of ecology is still at a relatively primitive state, it is very clear that interference in one part of nature (in the present sense) is liable to have unexpected and unwel- come consequences elsewhere. But not to interfere is no less liable to be disastrous, especially if the animal side of *human beings is included in this conception of nature and only our intellectual abilities are excluded and barred from taking action. m.r. L. Gruen and D. Jamieson (eds.), Reflecting on Nature: Readings in Environmental Philosophy (New York, 1994). J. S. Mill, Three Essays on Religion (London, 1874). J. Passmore, Man’s Responsibility for Nature (London, 1974). nature, human: see human nature. nature, state of: see state of nature. nature, uniformity of: see uniformity of nature. Naturphilosophie. Generally associated with the philoso- pher Schelling, Naturphilosophie was a widely supported although much derided general view of *nature, popular in Romantic German circles at the beginning of the last century. Owing much to Kantian *idealism, with a gener- ous dash of *Platonism, the Naturphilosoph saw the whole of reality underpinned by certain basic archetypes, which have ever more perfect manifestations as one moves up the chain of being. Significant in such areas as the newly developing theory of electricity, Naturphilosophie made its greatest impact in the biological sciences, especially through such notions as the vertebrate theory of the skull, where one sees all the bones of the mammalian body as variations on one theme, namely that of a typical piece of the backbone. Even in today’s biology, there are whispers of Naturphilosophie, especially through such claims as that of the American evolutionist Stephen Jay Gould that the key to understanding animal form is the repetition and modification of certain shared blueprints or Bauplane. m.r. *evolution; naturalism. A. Cunningham and N. Jardine (eds.), Romanticism and the Sciences (Cambridge, 1990). necessary and contingent existence. Entities are held to exist necessarily if *natural processes will not lead to their cessation, contingently if such processes will lead to their cessation. The distinction stems from Plato, who, concen- trating on the contrast with mathematical and other abstract entities, emphasized the corruptibility of ordin- ary spatio-temporal objects. Aristotle provided a physics which accounts for and indeed requires such (sublunary) corruptibility, and the distinction was famously utilized by Aquinas in the third of his five ways. By the later Middle Ages a number of such necessarily existing entities were known, such as human souls, angels, demons, the ‘heav- enly luminaries’, and God, who, unlike the others, does not have his ‘necessity from another’. In this sense of ‘necessary’ there is no entailment from ‘X has necessary existence’ to ‘Necessarily, x exists’. j.j.m. Patterson Brown, ‘St Thomas’ Doctrine of Necessary Being’, Philosophical Review (1964); repr. in A. Kenny (ed.), Aquinas: A Collection of Critical Essays (London, 1969). necessary and sufficient conditions. If a *conditional of the form ‘If p, then q’ is true, then the state of affairs expressed by p is said to be a sufficient condition of the state of affairs expressed by q and, correlatively, the state of affairs expressed by q is said to be a necessary condition of the state of affairs expressed by p. If the conditional in question is true of logical necessity, as in the case of ‘If this table is round, then it is not square’, then we may speak of logically necessary and sufficient conditions. Weaker con- ditionship relations are expressed by correspondingly weaker conditionals—for instance, the conditional ‘If this match is struck, it will light’ implies that striking this match is, in the circumstances in which the conditional is asserted, a causally sufficient condition of the match’s lighting. e.j.l. *causality; necessity, logical. E. Sosa and M. Tooley (eds.), Causation (Oxford, 1993). necessary statements: see contingent and necessary statements. necessitarianism: see determinism. necessity: see causality; contingent and necessary state- ments; natural or scientific laws; necessary and contingent 644 nature existence; necessary and sufficient conditions; necessity, epistemic; necessity, logical; necessity, metaphysical; necessity, nomic. necessity, epistemic. Sometimes the modal auxiliaries ‘must’ and ‘may’ appear to be used in an epistemic sense to express, respectively, what is entailed by and what is con- sistent with what a thinker knows. Thus, someone who knows that a train is due but has not yet arrived may assert ‘It must be late’, and one who knows that it is due but does not know whether it has yet arrived may assert ‘It may be late’. Epistemic necessity is often expressed in terms of *certainty, as in ‘The train is certainly late’. e.j.l. *knowledge. A. R. White, Modal Thinking (Oxford, 1975). necessity, logical. In the narrowest sense, what is logic- ally necessary is what follows from the laws of logic alone (though there is some debate over what those laws are). Thus, a statement like ‘Either it will rain or it will not rain’ expresses a logically necessary truth, because it is an instance of the law of excluded middle. Again, ‘If all men are mortal and Socrates is a man, then Socrates is mortal’ expresses a logically necessary truth, because in standard logic if we may deduce the consequent of a *conditional from its antecedent, then the truth of the conditional follows from the laws of logic alone. A sentence expressing a logically necessary truth, in this narrow sense, is true solely in virtue of its logical form: the meanings of any non-logical terms which it contains are irrelevant to its status as expressing a logical necessity. Thus ‘Either it will rain or it will not rain’ expresses a logic- ally necessary truth because it has the logical form ‘Either p or not p’. However, in a wider sense a sentence may be said to express a logical necessity if, although not itself a sentence true solely in virtue of its logical form, it may be transformed into such a sentence by replacing certain terms in it by other, definitionally equivalent terms. For example, ‘All bachelors are unmarried’ does, in this wider sense, express a logically necessary truth, because ‘bach- elor’ may be defined as ‘unmarried man’, and ‘All unmar- ried men are unmarried’ is true solely in virtue of its logical form. In this wider sense, logically necessary truths are often identified with *analytic truths. In a still broader sense, a logical necessity may be char- acterized as a proposition which is true in every *possible world, without restriction—that is to say, in every logically possible world, the assumption being that every such world is at least a world in which the laws of logic hold. This is sometimes called ‘broadly’ logical necessity and is assumed to conform to the principles of a system of modal logic known as S5, first formulated by C. I. Lewis. In that system—to give a simple example—if it is possible that p, then it is necessarily possible that p (because if proposition p is true in some possible world, then in every possible world it is true that p is true in some possible world. If the onto- logical argument is valid, then ‘God exists’ expresses a logically necessary truth in this broad sense, because the argument can be construed as concluding that that sen- tence is true in every possible world. It does not appear that ‘God exists’ could be said to express a logical necessity in either of the narrower senses previously mentioned, for at least two reasons. First, it is clear that ‘God exists’ is not a sentence which is true solely in virtue of its logical form—and it is doubtful whether the term ‘God’ could be replaced by a definitionally equiva- lent term, since ‘God’ appears to be a proper *name. Sec- ondly, it is very arguable, in any case, that no *existential proposition follows from the laws of logic alone. Broadly logical necessity seems to be closely akin to *metaphysical necessity, though the latter is, in general, assumed not to be knowable *a priori. e.j.l. *modal logic. G. E. Hughes and M. J. Cresswell, An Introduction to Modal Logic (London, 1968). A. Plantinga, The Nature of Necessity (Oxford, 1974). W. V. Quine, From a Logical Point of View, 2nd edn. (Cambridge, Mass., 1961). necessity, metaphysical. The notion that there is a kind of objective necessity which is at once stronger than phys- ical necessity and yet not simply identifiable with *logical necessity owes much to the work of Kripke. Logically necessary truths are, it seems, knowable a priori, but Kripke argues that metaphysical necessity is, typically, only dicoverable a posteriori—that is, on the basis of empirical evidence. For instance, Kripke holds that if an identity statement like ‘Water is H 2 O’ is true, then it is necessarily true—in the sense that it is true in every *pos- sible world in which water exists. However, plainly, we can only know that water is H 2 O on empirical grounds, through scientific investigation—and we might be mis- taken about this. It is vital, then, not to confuse meta- physical necessity with epistemic necessity. e.j.l. S. A. Kripke, Naming and Necessity (Oxford, 1980). necessity, nomic. The world of experience seems to be understandable and user-friendly primarily because it is reliable, in the sense that it is regular. This is not to say that everything happens in the same way on every occasion. Some people die of lung cancer, some do not. But under- lying the contingent happenstances of existence there seems to be order and regularity. The world runs accord- ing to rules or laws. Moreover, for all that these laws lead to different effects, it seems to us that in themselves they are necessary. It is not mere chance that water boils when it is heated, any more than it is chance that blue-eyed par- ents tend to have blue-eyed children or that spring follows winter as winter follows autumn. Wherein lies the source of this necessity? For Plato it lay in the relations between the Forms, and thus had at least the status of mathematical and logical necessity. For Christian philosophers, down to and beyond Descartes, it was a consequence of God’s power and goodness, and our necessity, nomic 645 ability to recognize it (given the right precautions and training) lay in the powers he had conferred on us. God could break this necessity at will, as he did whenever he decided to intervene miraculously in his Creation. But sceptics, most notoriously David Hume, have chal- lenged this presumption. They argue that there seems to be no logic to the necessity of experience. We may expect the sun to rise tomorrow, but (as Bertrand Russell pointed out) logically we are in no different position from the turkey who expects his lunch on Christmas Eve on the rea- sonable grounds that he has had such a lunch on every day previously. Things could go wrong at any time. Yet this is not to deny such necessity—generally called ‘nomic’ (meaning ‘lawlike’) to distinguish it from other sorts of necessity, like ‘logical’. Nor that it does seem to be marked by its ability to bear counter-factual conditionals. Suppose someone asks if a particular sample of a metal is copper. You heat it and find that it melts at 1,000 degrees centigrade. Thus you reply: ‘This cannot be copper, because if it were, it would melt at 1083.4 degrees’. If there is no such necessity, there can be no such counter-factual. Obviously, none of this explains nomic necessity or, perhaps more importantly, why we believe some claims about the world are thus necessary. With the coming of scepticism it has generally been realized that there does not seem to be something ‘out there’ guaranteeing that the world must run in a regular manner, and that even if God is maintaining his Creation, this in itself does not account for our feeling of necessity. Famously, Kant tried to explain things in terms of our psychology, namely that it is we ourselves who put the necessity into our perceptions, thus ensuring that it ends up in our understanding. Trying to regain some of the old security, he argued also that, as rational beings, this is the way that we must think. The imputation of nomic neces- sity therefore becomes a condition of rational thought. But although many would agree with Kant about the psychology, fewer would go on to agree about the additional claim. In a world which has challenged the necessity of traditional mathematics as well as traditional concepts of causation, it seems rash to suggest that we must think in the ways that we have always thought. One might argue that there can be no proof of nomic necessity and that therefore we should abandon it. This seems to be the position of Karl Popper, but most of us are not that convinced that one should throw out what seems to be a generally good guide to life. In any case, such advice is more easily given than followed. Can one or should one go through life pretending that every move into the future is a leap into the dark? One seems therefore to be thrown back just on psych- ology, which was essentially the position of Hume. Frankly, you cannot justify your belief in necessity, but fortunately your nature makes you believe in it, and that is quite enough for human living. The one point where some today think that they can go beyond Hume is in showing that our conviction about necessity is surely linked to our evolutionary origins, and that those would be ancestors who assumed necessity tended to outsurvive and outbreed those that did not. We may all be turkeys fast approaching Christmas Eve, but at least we are the descendants of those who had the biology to get through the summer. m.r. *laws, natural or scientific; necessity, logical; induction. N. Goodman, Fact, Fiction and Forecast (Cambridge, Mass., 1983). T. Honderich, A Theory of Determinism (Oxford, 1988), ch. 1. E. Nagel, The Structure of Science (New York, 1961). needs. An organism’s (basic, fundamental) needs are what it requires to live the normal life of its kind—flour- ishing rather than merely surviving—and if a need is unmet, the organism will suffer harm. Applying this analysis to human needs raises three related questions. Are human needs objective? Are they distinguishable from wants? Are they universal or culturally relative? It seems indisputable that human beings objectively and universally need air, water, food, and shelter, whatever cultural wants, desires, or preferences they happen to have. Objective human needs can plausibly be defined more abstractly as the necessary conditions for flourishing through the exercise of essential human capacities; in brief, physical and psychological health, and freedom. This account links needs to *human nature and naturalis- tic ethics. Needs are also the basis for an influential expli- cation of distributive justice. a.bel. *ethical naturalism. Len Doyal and Ian Gough, A Theory of Human Need (Basingstoke, 1991). negation and double negation. Negation is denial. When a person denies something, (1) her act, and (2) her assertion (i.e. what she asserts in so acting), are negations. (3) A proposition, even if not being used to assert anything, is the negation of another when it would, if asserted, deny—i.e. be the negation of—what the other would, if asserted, affirm. A negative particle or other expression, e.g. ‘not’, is one which can (amongst other things, and when suitably placed) take a sentence suitable for affirm- ing something and transform it into a sentence suitable for denying the same thing. (4) The resulting negative sentence is also called a negation. Is the negation of the negation of A equivalent to A? That depends on what denial is, and hence what negative particles mean. In logic the classical answer is ‘yes’, and accordingly operations of eliminating and introducing double negatives are permitted. Intuitionist logic dis- allows the elimination. c.a.k. *logic, intuitionist. G. Frege, ‘Die Verneinung’, Beiträge zur Philosophie des deutschen Idealismus (1919), tr. P. T. Geach as ‘Negation’, Translations from the Philosophical Writings of Gottlob Frege, ed. P. T. Geach and M. Black (Oxford, 1952). H. Price, ‘Why “Not”?’, Mind (1990). A. N. Prior, ‘Negation’, in P. Edwards (ed.), The Encyclopedia of Philosophy (New York, 1967). 646 necessity, nomic negative and positive freedom: see liberty. negative proposition: see affirmative proposition. negritude. A black consciousness movement originating in the 1940s in the prose and poetry of Aimé Césaire of Martinique. It received its specifically philosophical dimension from the varied publications of Senghor, past President of Senegal, who argued, among other things, that African cognition is marked, principally, by an emo- tional rationality which knows through embrace rather than through the dissection characteristic of Western ana- lytical rationality. This doctrine has had a mixed reception among African intellectuals. k.w. *black philosophy. Senghor: Prose and Poetry, ed. and tr. John Reed and Clive Wake (London, 1965). neo-Confucianism. A revival of Confucian philosophy in Sung dynasty China, distinguished by an interest in ontol- ogy prompted by influences from Taoism and Buddhism, and with a later efflorescence in Japan. The major figure was Chu Hsi (1130–1200), who developed a sophisticated philosophy according to which a dynamic universe results from the interplay of a supreme ordering principle (t’ai ch’i, or li) with a medium of matter–energy (ch’i). Chu Hsi’s thought was developed with greater emphasis on ethical issues by Wang Yang-ming (1472–1529), who made the idea of the human heart–mind (hsin) foundational. Schools based on their teachings came to flourish in Japan, together with a movement known as the Kogaku (‘ancient learning’) school, whose primary representatives were Ito¯ Jinsai (1627–1705) and Ogyu¯ Sorai (1666–1728). Placing unprecedented emphasis on philological concerns, these thinkers led a return to the careful study of the earliest texts of the classical Chinese canon. g.r.p. *Confucianism; Buddhist philosophy. Wing-tsit Chan (ed.), Chu Hsi and Neo-Confucianism (Honolulu, 1986). neo-Kantianism. Neo-Kantianism was a family of schools in *German philosophy from about 1870 to about 1920. It was marked by repudiation of *irrationalisms, speculative *naturalisms, and *positivisms. It was motivated by the conviction that philosophy can become a science (and not just a world-view) only if it goes back to the spirit of Kant, in whom epistemology was seen as propaedeutic to meta- physics and all other philosophical disciplines. There were, of course, many ways to understand and follow so complex a thinker as Kant, and the historian of philosophy Windelband was correct in saying that ‘To understand Kant means to go beyond Kant.’ So numerous were the philosophers who sought Kantian foundations for their diverse systems that historians cannot agree on how many neo-Kantian schools there were (two? seven?) or on which school to assign many philosophers to. In spite of (or, per- haps, because of) this diversity, neo-Kantianism was the dominant philosophy in the Wilhelmine universities and it maintained this hegemony until phenomenology, posi- tivism, and philosophy of life began capturing the best minds in the early twentieth century. After the death of Hegel in 1831 Germany entered a period of philosophical sterility during which the flourish- ing natural sciences and their reflection in materialism and positivism reigned in the universities. Especially after the Revolution of 1848 the position of philosophy in the uni- versities had become politically compromised. A few philosophers who attempted to maintain some traditional philosophical position (e.g. theism) or to develop their own philosophical system (e.g. Eduard von Hartmann) bowed in the direction of Königsberg. Outstanding among these proto-neo-Kantians was Hermann von Helmholtz (1821–94), the great scientist who gave a genetic, physiological account of sense-perception with empirical analogies to Kant’s transcendental psychology. But there was no concerted effort to rehabilitate Kant; per- haps there were neo-Kantians, but no neo-Kantianism. Marburg neo-Kantianism. In 1865 Otto Liebmann (1840–1912) published his Kant and the Epigoni, in which all the epigoni were accused of a common fault, the accep- tance, sometimes disguised, of unknowable *things-in- themselves. Each chapter of this manifesto closed with the epigraph: ‘We therefore must go back to Kant!’ This book was followed a year later by Friedrich Albert Lange’s clas- sic History of Materialism, in which Lange showed that there were Kantian epistemological foundations for materi- alistic science, but rejected the metaphysics of Kant’s Dialectic and regarded all talk of unknowable supersens- ible things as mere fantasy. Lange became ordinarius in Marburg in 1872, and one year later he was joined by a stu- dent of Adolf Trendelenburg in Berlin, Hermann Cohen (1842–1918), who succeeded Lange upon his death in 1876. Thus was established the Marburg School. Cohen began his career writing commentaries on Kant’s three Critiques, and he expounded his own philoso- phy in three volumes corresponding to the three volumes of commentary. All six volumes tried to replace Kant’s psychologistic theories (intuitions as passively received; thought as organizing intuitions; the creation of images, etc.) with Cohen’s own understanding of the transcen- dental method. This method begins not with the facts of perception or self-observation, but with the fact (Facta) that science, ethics, and law exist as cultural products. Only that which the mind has conceptually established can be known a priori. Science is not the study of given facts—nothing is *given (gegeben), says Cohen; ‘all is assigned (aufgegeben) as a task’ of producing categorially constituted scientific facts. Cohen interprets this produc- tion on the model of integration in mathematical know- ledge. There is no thing-in-itself; but the concept of the thing-in-itself is essential as a limiting concept of the goal of knowledge approached asymptotically. Paul Natorp (1854–1924), Cohen’s disciple and succes- sor, carried through investigations in the foundations neo-Kantianism 647 of post-Einstein physics; then he applied Cohen’s tran- scendental method to psychology itself. In his Platons Ideenlehre (1902) he gave a Platonistic account of Kant’s categories and transcendental ideas (or, alternatively, he Kantianized Plato’s theory of Ideas). After Cohen’s retire- ment Natorp became a more independent thinker, and the distance between Heidelberg and Marburg became noticeably less. The last important representative of Marburg neo- Kantianism was Ernst Cassirer (1874–1945), who replaced the cognitive categories with a series of ‘symbolic forms’ which generate a priori structures not only in science but also in mythology, language, and politics. The Heidelberg School. The Heidelberg School does not show the simple pattern (Gestalt) of the Marburg. In fact it is sometimes called the Baden or the South-West German School, since its masters were sometimes in the Univer- sities of Zurich, Freiburg, and Strasbourg; the founding father of the school, Kuno Fischer, was for a time banished from Heidelberg. The long (1865–72), vituperative, and scurrilous controversy between him and Adolf Trendelen- burg (Cohen’s teacher in Berlin) over whether Kant had shown that space and time were only forms of intuition or also forms of things-in-themselves divided German philosophers into two camps, with adherents of both sides publishing more than fifty polemical papers on the quarrel. Köhnke wittily says: ‘Just as in Charlottenburg, in Berlin, two parallel streets, a Kuno Fischer Strasse and a Trende- lenburg Strasse lead to the Neue Kant Strasse, so the road to Neo-Kantianism led either through the school of Fischer or that of Trendelenburg’ (The Rise of Neo- Kantianism, 170). Kuno Fischer was pre-eminent as a historian of philoso- phy, and his influence was felt in the second and third gen- eration of the Heidelberg School. Wilhelm Windelband (1848–1915), as a historian of philosophy, was the natural heir to Fischer, and Heinrich Rickert (1863–1936) was at his best in providing a philosophy of historiography. Windelband produced only one large work—his The His- tory of Philosophy (still a classic)—and one must gather his systematic thoughts from scattered papers, or by reading Rickert, who had a more systematic mind than his master. The basic fact with which Heidelberg neo-Kantianism begins is that there is a cognitive as well as an ethical imperative; logic is the ethics of thinking. The world is not as we perceive it, but as we must perceive it, where this must has the modality of ethical or more generally of a Geltungs-imperative (Geltung = validity). There is an absolute ought and must whose categorial structure we establish, and this is specified into truth, goodness, beauty, and holiness. Philosophy is the study of the validity (Geltung) of norms, universal rational necessities, and a priori forms of all culture. Windelband’s successor, Heinrich Rickert, likewise extended Kant’s primacy of practical reason to theoretical philosophy. He interpreted valid norms as anchored in the a priori structure of a value-world (Wertwelt). Perhaps Rickert’s most important contribution was developing Windelband’s distinction between the nomothetic sciences, which generalize (e.g. the natural sciences), and the ideographic sciences, which individuate (the historical and human sciences). Each has its own a priori categorial structure. This hasty review of neo-Kantianism has had to omit many German philosophers who did not found, or did not belong in, any school, but whose contribution to an understanding and use of Kant in later philosophy was perhaps as great as that of the philosophers reported on here. We can only mention the most prominent names: Hans Vaihinger, Friedrich Paulsen, Aloys Riehl, Leonard Nelson, and Georg Simmel. l.w.b. *Kantianism. Ernst Cassirer, ‘Neo-Kantianism’, in Encyclopaedia Britannica, 14th edn. Klaus Christian Köhnke, The Rise of Neo-Kantianism: German Acad- emic Philosophy between Idealism and Positivism (Cambridge, 1991). Thomas E. Willey, Back to Kant: The Revival of Kantianism in German Social Thought 1860–1914 (Detroit, 1978). Neoplatonism. A later form of Platonic philosophy that had its primary development as a school of thought in the Roman Empire from the third to the fifth century ad. Countering dualistic interpretations of Plato’s thought, it is a highly monistic version, namely, one that posits a superexistent Source of all being that extends itself into various lower levels of being, with each lower level being a weaker extended expression of the level just above it. Its founder was Plotinus (204–70), a Hellenized Egyptian who at the age of 40 established an academy of philosophy in Rome and taught in it for the next twenty-five years. Some of its basic tenets, however, likely came from his teacher, Ammonius Saccas (185–250), with whom he had studied philosophy in Alexandria for eleven years when he was a young man. The term ‘Neoplatonism’ itself is of fairly recent origin, going back only to the mid-nineteenth century when German scholars first used it to distinguish the views of the later Greek and Roman Platonists from those of Plato. Plotinus saw himself as a latter-day disciple of Plato, and urged his Roman contemporaries to return to Plato’s teachings. He wrote only one book, a series of fifty-four carefully reasoned philosophical essays composed over a period of fourteen years late in his life. His disciple, fellow teacher, biographer, and critic Porphyry (c.232–304) later edited and arranged them into a book with six divisions of nine essays each, called the Enneads (the Nines). Although in the Enneads he always defers to Plato, Plo- tinus is very much aware of the teachings of Aristotle, and mentions Aristotle more times than he does Plato. More specifically, he is aware of Aristotle’s objections to Plato and seeks to overcome them through his own revised ver- sion of *Platonism, a version in which he endeavours to retain the basic teachings of Plato, but to reshape them in a new rational metaphysical system similar in type to the 648 neo-Kantianism metaphysical system of Aristotle. In this sense, he can be considered to be an Aristotelian Platonist, or even, as one scholar has suggested, a neo-Aristotelian. He also shows his knowledge of both Gnosticism and *Stoicism and inte- grates some elements of the latter into parts of his own system. He was familiar with some of the purely mystical philosophies that flourished in the Roman Empire at the time, and presents his own philosophy as a strong form of rationalism in reaction to them. In the Enneads, he affirms the same themes common to the general Platonic tradition, namely, (1) the non- materiality of the highest form of reality, (2) belief that there must be a higher level of reality than visible and sensible things, (3) preference for intellectual intuition over empirical forms of knowing, (4) belief in some form of immortality, and (5) belief that the universe is essen- tially good. The difference, however, is that Plotinus affirms all of these as a monist interested in asserting a real identity between the natural and the supernatural both in man and throughout all of nature. In his metaphysics Plotinus sets forth his vision of the logical structure of all being and sees two movements run- ning throughout the whole of nature, namely, the com- ing-out of all things from their original unitary source, and their subsequent return back to that source. He attempts to answer the primary question of Greek metaphysics ‘How does the one become many?’, by positing an Ultim- ate Being, the One, as supernatural, incorporeal, self- caused, absolutely free, and absolutely good. Since it is absolutely good it necessarily extends its goodness and power into all lower beings. Without any loss of any of its own essence, it projects itself into lower stages of itself to form lower and weaker beings. The first stage of this pro- jection is *Nous, or Mind, and the second is Psykhe¯, or Soul, which in turn is a projection of Nous. All things in nature, namely, all life-forms and all corporeal beings, including man, are souls. As such they are both in a state of becom- ing and dependent upon Nous for the fixed orders of their being. Thus the one becomes many by the necessary extension (proödos) of the One into lower, progressively weaker multiple phases of itself as the principles (Nous) and life-forms (Bios) of all natural things. The many, in turn, always seek to return to the one, for all natural things seek to return (epistrophe¯) to some higher unity as their source. Most of the credit for the survival of Neoplatonism must go to Porphyry, Plotinus’ successor in his academy. Porphyry differed from Plotinus on some points; and by denying some of the categories that Plotinus affirmed, and substituting for them some of Aristotle’s categories, he created another type of Neoplatonism. As a matter of fact, his version of Neoplatonism later had a greater impact on the development of early European philosophy than did the Neoplatonism of Plotinus. Other versions of early Neoplatonism also emerged in later centuries. One of Porphyry’s students, Iamblichus (c.250–326), returned to his native Syria and founded the Syrian School around 300. The Pergamum School was founded around 330 by Aedesius, a former student of Iamblichus. Its most famous member was the Roman Emperor Julian, called Julian the Apostate, who died in 363. The School of Athens was founded by Plutarch of Athens, at the end of the fourth century. Its most famous proponent was Proclus (410–85). Proclus is now regarded as the third most important Neoplatonist after Plotinus and Porphyry. His ploy was to use the concept of triads, or evolutionary development by triadic extensions, both ver- tically and horizontally to explain the interconnectedness of all things. This school continued in Athens until 529 when it was closed by decree of the Emperor Justinian. One of Proclus’ pupils, Ammonius, was instrumental in establishing the Alexandrian School in the fifth century, a school which lasted until the end of the sixth century. Among its members were Simplicius, Olympiodorus, and Hypatia, the famous female philosopher and math- ematician who was pulled from her carriage and killed by a mob of Christians. Both Plotinus and Porphyry rejected Christianity because of its personalistic brand of supernaturalism and doctrine of salvation by grace through faith. Porphyry even wrote a book entitled Against the Christians. But their rejection of Christianity did not prevent some later Chris- tian philosophers from importing large elements of Neo- platonism into their own philosophies. Notable among these were: some of the Greek Church fathers, such as the Cappadocians, Basil and the two Gregories, the great Latin Church father St Augustine (354–430), Boethius (470–525), Eriugena (c.820–70), and St Thomas Aquinas (1225–74). Marsilio Ficino’s translation of the Enneads into Latin in 1492 introduced Plotinian Neoplatonism with its broader humanism into Italy and later into some other European countries. It was taken to England in the late 1490s by John Colet, who paved the way for the emergence in the seven- teenth century of a group of English Christian Neoplaton- ists known as the *Cambridge Platonists. Certain medieval Jewish thinkers also imported elem- ents of Neoplatonism into their philosophies. Notable among these were Isaac ben Solomon Israeli (850–950), Avecebrol (1020–70), and Abraham Ibn Ezra (c.1092– 1167). Some Islamic philosophers did the same. Notable among them were al-Kindı¯ (d. c.866), al-Fa¯ra¯bı¯ (c.870– 950), Avicenna (980–1037), and Averroës (1126–98). Neo- platonic themes may also be found in Meister Eckhart (1260–13 27), in Nicholas of Cusa (1401–64), in most of the German idealist philosophers, in a few French philoso- phers, especially in Bergson, and in some British poets (Blake, Shelley, Keats). They also occur in Jonathan Edwards and Emerson and the *New England Transcen- dentalists in America. Neoplatonism emphasizes the necessity of both reason and experience in philosophy and sanctions the idea that human experience may even go beyond metaphysics on rare occasions. As a holistic form of thinking it can serve as a prototype for the production of some greatly needed forms of holistic philosophy for our own age. r.b.h. Neoplatonism 649 . reaction to them. In the Enneads, he affirms the same themes common to the general Platonic tradition, namely, (1) the non- materiality of the highest form of reality, (2) belief that there must. opinion therefore inclines to the belief that the distinguishing mark of the organic lies in its high degree of organization rather than anything physical as such. To the Darwinian, as to the natural. we came by the belief in question, or, if the ‘we’ is not an individual but a, or the, scientific community, then an account of the rele- vant part of the history of science up to the time in