The revival of Aristotelian doctrines led by Aquinas and Albertus Magnus had been of incalculable benefit to pre-renaissance thought. Opposing the tendency to regard the natural world as merely an agglomeration of largely disjunct symbols, expressing moral or theological truths, it had re-established it as a worthy object of study in its own right. Holding that to differing fields of speculation pertained, particular and independently valid methods of enquiry, it relieved the stultifying pressure produced by the attempt to make continuous reference at each point to theological standards, and to bring all knowledge into too immediate and unequivocal conformity with them. Its teachings on the status of universals and on the function of "illumination" had, in contrast to Anselm's position, insisted on the necessity of admitting observation as an original datum for the discovery of truth in many departments of knowledge, instead of merely stigmatising it as a very fallible operation that might sometimes be usefully employed to illustrate truths which the intellect was able quite independently to attain, without recourse to any assistance from the senses. Of the defects of the preceding Augustinian Platonism, Mandonnet writes: "Les inconvenients etaient dans la methode peu didactique, visant a la speculation ideale en negligeant les donnees experimentales de la science, et utilisant la raison et la foi sans definir sufficamment leur domaine," and while here there was an "absence d'une distinction formelle entre le domaine de la philosophie et de la theologie, c'est a dire entre l'ordre des verites rationelles et celui des Verites revelees," for the Thomists "l'objet de la science et celui de la foi sont strictement definis, et declares irreductibles l'un a l'autre et les traites de science pure executes sans toucher jamais a une question theologique."(62)

Truth, it has been said, emerges more readily from error than from confusion. Aristotelianism provided a method of analysis and an orderly framework for the rational correlation and interpretation of natural phenomena. Taken as "an example of a majestic inductive generalization appealing to the obvious facts, and neglecting the welter of minor differences, Aristotle's general conception of the physical universe remains unsurpassed. For every feature in it there is an appeal to observation, and for every observation to which appeal is made there is the possibility of indefinite repetition."(63) As a detailed illustration: "La theorie du lieu naturel, telle qu'Aristote l'avait proposee, etait une bonne theorie de Physique, car, au moyen d'un petit nombre d'hypotheses elle permettait de classer une multitude de phenomenes connus, de prevoir une foule de repos ou de mouvements."(64) It thus represents a step forward in the unification of the world through the mediation of general concepts and natural "laws." In many respects - the instance above is a noticeable one - its potentialities had been fully exploited in a period prior to the Renaissance, and it became more and more inadequate as a means of fruitfully resolving problems, and problems which to a large extent it may be said to have originally been itself responsible for revealing and clarifying. Its gradual, sometimes piecemeal abandonment, was not the result of any direct refutation. The rise of the new scientific methods and physical theories is rather an indication of the way in which "ideas which make sense in one age, in illuminating and co-ordinating its intellectual experience, do not necessarily make sense in the same way in another. Therefore there is likely to be a shift in the philosophical analogies which will commend themselves as self-evident in different periods of thought."(65) The scientific "neoplatonism" of the Renaissance was not a single coherent body of doctrine suddenly set up in formal and total opposition to previous thought; it made considerable efforts to incorporate with a minimum of change as much as possible of earlier findings and theory, particularly in various sciences such as medicine; it is characterised, rather, by a change in standpoint, and a change in the distribution of emphasis as regards the relative importance and priority of various aspects of knowledge.

Some typical features of Aristotelian thought reveal clearly the causes of its increasing inadequacy or irrelevancy for the scientific demands of the Renaissance. It had sought to categorise and explain the natural world in terms of the qualitative experiences of the normal man, taking the complex and dangerously uncoordinated syntheses made with a deceptive appearance of "naturalness" and "inevitability" by common sense, as simple and fundamental. "It is the familiar," Aristotle had declared flatly, "that is intelligible."(66) A general process of extrapolation based on ideas of the "familiar" produced such assertions as that the earth can be nowhere except at the centre of the world, because it would clearly sink to that place were it ever anywhere else, since "only a careless mind would not wonder at the suggestion that though a small piece of earth falls if unsupported, if one held the whole earth in the air and let it go it would not move"(67); a view reflected by the argument Galileo puts in the mouth of Simplicius; that the acceptance of Copernicus' theories would mean the subversion of the fundamental criterion of Natural Philosophy - since "Sense and Experience" must always be taken as guides. But checked rather than assisted by the way these were interpreted by Aristotelianism, that is in terms which possessed much superficial plausibility and immediate appeal but were internally extremely complex and refractory to further analysis, the Renaissance was to find that more abstract concepts were not merely more useful in practice but intellectually more simple and satisfactory.(68)

Aristotelianism provides a sharp contrast with what is perhaps the central most fundamental procedural assumption of Platonism, which, insisting that "knowledge" of things is dependent on and determined by the reason, ascribes "Reality" and "Being" to these in the degree to which they manifest "intelligibility," and therefore regards their essence as produced by the same principles from which true discursive reasoning proceeds, which principles forming a hierarchy of more and more generalised "truths" are to be attained by employing discourse reflexively to reveal its own structure; meaning therefore, as a result of such an analysis of discourse is resolved into coherency, and the conditions under which a proposition is admitted as intelligible within the systems are also taken as the grounds for any predication of "existence." In contrast with this approach Aristotelianism presents a "meroscopic" view: the principles of discursive knowledge are held to be undemonstrable, and intuitive, no metaphysical significance is consciously granted them, they have no synthetic content, reason is not productive or formative but only a method of ordering previously known facts and special sciences have particular principles, produced, or at least determined, as it were from below, by the particular nature of the subject matter with which they deal. The world is built up of original atomic facts to which, rather than to the generalisations to be obtained from them by reason, "reality" is to be ascribed. But in regarding the concept as something obtained merely by "abstraction," from things themselves, a priori assumptions, in a particularly vicious form because unobserved, have been made, for the concept has already been essentially presupposed in the generalisation that selected the group of "similar" things from which it is to be abstracted. But the drawbacks are concealed, some immediate advantages obvious. It is an attempt to save the appearances by departing from experience as little as possible. A "copy" theory of knowledge results: a noumenal reality is constructed closely analogous to a selected range of perceptions and employed to account satisfactorily for appearance (69). From the confused flux of sense data are to be extracted a set of qualitative manifolds which, granted unity, necessity and permanence, will form the basis of knowledge, which could not be built merely on the succession of appearances of things "which are subject to change and never remain in the same state."(70)

The standard of objectivity is here thoroughly qualitative, and ultimately unintelligible. For while Platonism tended to regard the thing only as existing in, as generated by, a context of ideas which allowed of a complete rational analysis, here substantiality is prior to formula, things are set beyond the mind and given independent status in themselves, since they have essences, which are what each thing "is said to be per se," "what a thing is said to be of its own nature"; and though this essence is expressed by a definition (71), the elements, or qualitative simples which the definition uses are themselves unanalysable further, they are entities existing beyond the scope of definition: "we cannot say what silver is though we can say that it is like tin."(72)

The multitude of "forms" which compound the world may be classified in a manner that reflects Aristotle's biological predilections - they are arranged, not causally related. Methods which attempt a more fundamental correlation of phenomena, seeking thus to unify the mass of disparate, independent irreducible qualitative fragments which form the unexplained explanation of Aristotelian nature, are rejected or denigrated. Physics and sciences employing mathematics are declared not to study "being qua being" for quantity as applied to things is always changing, and itself is only "notional," which quality is not "sweetness such as it has never yet changed, and that which is to be sweet is necessarily of such a nature."(73) But "there is nothing permanent in respect of quantity....It is by the form that we recognise everything,"(74) and thus "Essence depends upon quality and this is of a determinate, whereas quantity is of an indeterminate nature."(75)

Despite its appearance of continual reference to concrete externals, there is truth in the charge so frequently made by seventeenth century thinkers that Aristotelianism really dealt with words not things. For the justification of its analysis of reality rests heavily on the assumption that there is direct access to facts through language - or rather a certain way of using language. For truth is not sought as in a Platonic dialectic, by an examination of the forms in which language conditions the discriminations and evaluations made by the mind, which its analysis of the interrelations of ideas amounts to, but is supposedly reached by an uncritical acceptance of the false objectifications which occur in its everyday use. "Names" it is argued stand for "passions of the soul," which are "images of things" and "the same for all men." They must be accepted as having one, or a limited number of meanings, for "if they have an infinite number there can be no discourse, for not to have one meaning is to have no meaning," and this single meaning is supposed to have a qualitative, perceptible nonrelational reference, which when definable, is taken as expressed by that definition, as being what the word was "intended to mean" (e.g., "man," "two-footed animal")(76). The complex of qualities that names so definable denote is held to be not a mere summative plurality but a genuine unity (77). It is as "wholes" that essences have reality, since they can apply to an indefinite number of discrete particulars, and the qualities by which such particulars are distinguished from each other are sharply differentiated in status from those making up the features they have in common; they are labelled "accidental - that which is not necessary or usual,"(78) but the "necessity" is of course, merely given by the defined name; which is in turn only allowed to be known from the things themselves (while the word "usual" indicates the inadequately critical foundations on which this division of natural appearances rests). For while it is strongly asserted that things are not merely collections of accidents - that there must always be something primary, relatively unchanging, to serve as a genuine subject in predicative statement (79), the criteria serving, by the instrumentality of defined forms, to distinguish the accidental from the essential features of a thing are drawn from the contents of an average educated perception presented in, and conditioned by, normal linguistic usage.

The picture thus offered of reality might be compared to a map which eschewing abstract symbolism indicates towns, forests, escarpments, etc. by miniature, only slightly formalised, representations of them all: it makes a certain appeal to the imagination, what information it offers is readily intuitively laid hold on, but it obscures many essential connections. Thus the belief that all true causality was to be found in quiddity, and that the technique of syllogistic reasoning accurately symbolized the rationalism underlying physical process, meant that the middle term of syllogism became confounded with what was causative in Nature (80), and the implication of a consequence seemed therefore identical with the mechanical production of an effect (Socrates, it is concluded is mortal since he is a man, his being "man" is therefore the cause of his death). The type of thought resulting from this hypostatising of the qualitatively definable concepts - which function as formal causes - and its disadvantages for the new science is well illustrated by a passage from Robert Recorde's Castle of Knowledge (81). Recorde, a coadjutator and friend of Dee's, here offers instruction in astronomy to a scholar who, apart from mathematics, seems already to have received a fairly good education, possibly a university one, along traditional lines. After dealing with the daily movement of the sun, Recorde is about to describe the annual motion producing the variation in the time it is above the horizon on successive days throughout the year, but the scholar breaks in. "Yet the reason of that is easy enough to be conceaved, for when the daye is at the longest, the Sonne must needes shyne the more tyme, and so must it needes shyne the lesser tyme, when the daye is at the shortest: this reason I have hearde many men declare." This, comments Recorde, may well be called a crabbed reason "for it goeth backwards lyke a crabbe," and proceeds to enquire further from his scholar of the cause of the longer or shorter days, and is answered "I have heard wise men say, that Sommer maketh the longe dayes and wynter maketh the longe nyghtes."

This passage is part parody, but it points to a genuine danger. Aristotle had declared that "it is impossible for the same attribute at once to belong and not to belong to the same thing and in the same relation,"(82) but the significance of the final all important phrase, could easily be overlooked, particularly after a thoroughgoing objectification of quality. If hot and cold were to be conceived as opposing, mutually exclusive substances, it became a real problem as to how different things might be respectively warmed or cooled by the same breath. Nevertheless, employing such an approach, an orderly and imposing scheme of nature had been already constructed by the time alternative philosophies began to make their appearance in the Renaissance. It referred constantly to experience, and attempted experiment. The type of experimentation it gave rise to and the conclusions drawn from them are illuminating. It could be demonstrated sensibly (i.e., by touch) that water was colder than the surrounding air, or when turned to ice was colder than the air it had frozen in, and exposed in winter cooled below the level of coolness perceptible in its container. This "intrinsic reduction," was ascribed to "the form" of water by Avicenna, and with more verbal precision to its "virtual frigidity" by Albert of Saxony (83). Again if two open vessels of water were taken, and one of them stood on a fire until its contents boiled, and then both were placed in the snow, the boiling water, it was maintained, might always be observed to freeze sooner than the cold water (a consequence of the rapid evaporation of much of the boiling water) which experimentally confirmed the prediction which could rationally be drawn from accepted physical theories, that the natural tendency of water to cool would be accelerated by the repulsion produced by the heat with which it had been enforcedly and unnaturally associated, since opposite qualities such as hot and cold violently repelled each other when brought into proximity. (Since indeed the rate of cooling in water is at any moment directly proportional to the amount by which its temperature exceeds that of its surroundings and the process becomes increasingly "slow," this Aristotelian thesis might claim to be "confirmed" by general observation.) Now it is quite irrelevant to urge that the plausibility of these two typical experiments rests merely on the facts that, in the one instance the thermometer had not been invented, in the other that the quantities of water left in each vessel, at the conclusion of the experiment were never measured. They represent a completely different orientation of the attention to the one which we are accustomed to regard as normal in scientific practice. The complete lack of interest in quantitative considerations is a product of a philosophical outlook not of technical difficulties. There is every reason to suppose that such experimenters would have regarded the behaviour of mercury in a tube as by far the less preferable and reliable guide to reality and the truth of things than direct perception, and would have defended the position that the quantity of water is irrelevant to the study of the rate and manner in which water cools in accordance with its own nature.

On such methods a fairly comprehensive, self sufficient schematization of the world was drawn (84), which, if "the recording augmentation, and rational correlation of those elements of our experience which are actually or potentially common to all normal people"(85) be allowed as an adequate definition of Science, cannot be denied that name, though its qualitative foundations prevent it being called so in the sense of being "a particular scheme of correlation of experience, which is not intrinsically limited with respect to the kind or amount of experience with which it may deal,"(86) but which is distinguished by the character of the single type of simple, rational, but not necessarily imaginable, universally applicable, correlation it aims to establish. Such a scheme mathematics offers, and Aristotelianism persistently trying to preserve the qualitative richness of perception and to defend its "reality," was driven into realms quite as abstract but far less accessible to reason. Thus "the forms of qualities and the matter of natural bodies" admits Alfarabi, "are not sensible, we are certain of their existence only by syllogism and apodeictic demonstration."(87) Tymme, an alchemist friend of Dee's writes of Form, Substance and Quality "I doe not thinke that anything can be defined concerning these which is either certaine, constant, or approved by generall consent, so long as man's minde is shut up in the prison of his body, neither can he know by his sense what Matter and Form is."(88) An analysis of the world into such terms as these had little practical utility; its connection with "natural magic" will appear later, but generally it was of little help in providing a method for the further investigation, or imitation or control of nature.(89) It was based on a purely contemplative survey of "experience," and it satisfied by its arrangement of the elements it discriminated therein the needs of the intellect to discover order and coherency there. The defects of its method of doing so, Roger Cotes points out in his Preface to the second edition of Newton's Principia: those who follow it "have attributed to the several species of things specific and occult qualities, on which in a manner unknown they make the operations of the several bodies to depend. The sum of the doctrine of the schools derived from Aristotle and the Peripatetics is herein contained....And being entirely employed in giving names to things, and not in searching into things themselves, we may say, that they have invented a philosophical way of speaking, but not that they have made known to us a true philosophy." Such occult qualities remarked Newton at the close of the Optics "put a stop to the improvement of natural Philosophy," since "to tell us that every Species of Things is endowed with an occult specifick Quality by which it acts and produces manifest Effects, is to tell us nothing."(90)

The chief method of investigating these formal causes was held to be the determination of the end, the perfection, to which they tended, their appearance or expression in matter at any moment could then be interpreted as a stage in a predictable course of development. But such ends were particular to each species. Hence while later science has almost consistently rejected a division of nature into a multitude of small "Wholes" in favour of the fewest possible number, however "unimaginable," of large ones (thus reducing the number of unanalysable, and therefore perhaps unintelligible elements employed, unanalysable because it is in terms of them that everything else is to be explained), their sphere of validity extending as they become progressively more abstract, Aristotelianism, following the normal manner of operating evidenced by "common sense," did the reverse. The usual assumption of Platonism was, as Cusa expressed it, that all things were ultimately related, in a manner which, however directly inconceivable to the mind or senses, made them into a genuine structural unity, sprung from the all containing unity of God.(91) Some of the applications of such a doctrine, as will later appear, may seem fantastic or perverse, but it played a part in the evolution of ideas of universal law, and leads on to the attitude Newton expresses, in the continuation of the passage just quoted "to derive two or three general Principles of Motion from Phaenomena, and afterwards to tell us how the Properties and Actions of all corporeal things follow from those manifest Principles, would be a very great step in Philosophy, though the Causes of those Principles were not yet discovered." In the Aristotelian scheme there is excessive and crippling heterogeneity. For instance, despite continuous attack from platonist critics - Grescas is a good example here - the dogma of the complete discontinuity, in type and principles of motions, maintaining in the sub- and supra-lunar regions, as well as in the constitution of the bodies occurring in each of these, was not seriously weakened until the Renaissance. Again special Arts and sciences were governed by separate unconvertible methods, and the validity of their principles restricted to particular ranges of subject matter. Cardan quotes as authoritative Aristotle's declaration in the Posterior Analytics that "it is not possible to demonstrate from any genus to another superior one, as from Arithmetic to Geometry: and Averroes states in his great commentary explaining these words: Demonstration cannot be transferred from one Art to another." Thus although, Cardan argues, there must be three worlds, corporeal, incorporeal, and that of living beings, they are utterly discrete, "there is no proportion among them, nor can they be defined by number."(92) Such "universal" laws as might be admitted had no necessary relation with those governing particulars. An interesting example is the treatment of the rise of water - against its own nature - into a vacuum, as treated by Joannes Canonicus in his Quaestiones on Aristotle's Physics (93). It is not considered there as representing the resolution of a previous conflicting interaction of forces or "laws," but is explained in effect, as the temporary complete abrogation of the law governing the particular nature of water causing it to tend downwards, in a situation that has called into operation the universal therefore more privileged "law" which does not permit a vacuum to exist in the world.

One consequence of this, directly related to Aristotle's rigid distinction between the three branches of speculative philosophy, i.e., Theology, Mathematics and Physics, was markedly alien to a widespread intellectual outlook in the Renaissance. This was the comparatively low level of value ascribed to human reason insofar as it might profess to aim at the discovery of ultimate truth, and the very restricted province, that on this evaluation might, logically, only be allowed to it. Even Aquinas, who strongly attacked the Averroist doctrine of a "double truth (94), seems in this respect to assert only the compatibility of reason and faith, and to allow philosophical reasoning merely a negative role - that of purging away errors - while philosophy for Platonic thinkers, such as Pico, "c'est la foi elle meme presentee sous l'aspect rationnel."(95) But the doctrine of the "double truth" was a logical if extreme consequence of the heterogeneity admitted into the Aristotelian picture of the world. It was thrown into greater prominence when Aristotelianism was brought into close conjunction with Christian orthodoxy, more especially as scholars, still maintaining Aristotle's authority, gradually stripped away the superimposed, modifying neo-Platonic features, which had considerably assisted the original reconciliation. Nevertheless, though there can be little doubt that a "Christian Averroism" is chiefly responsible, and provided perhaps the only possible framework, for the growth in the Middle Ages of an autonomous and thoroughly empirical physic, as, for instance, at Padua, yet such an attitude as Siger's, who "lorsqu'il expose quelques-unes de ses theses les plus hardies et en contradiction manifeste avec l'enseignement chretien, il declare ne pas determiner ses solutions selon la verite, mais bien suivant l'intention d'Aristote, et il laisse clairement entendre que ses conclusions sont celles de la raison naturell," (96) wherever it was held sincerely, as it would widely seem to have been, did not offer encouragement, or much inducement to the study of the natural sciences insofar as they were not of immediate and apparent utility. Moreover, whether sincerely professed or not - and for example one may perhaps legitimately suspect irony in Pomponazzi's submission of his reason to the higher otherwise incredible truths of revelation, or that Francis Bacon, recommending a similar denial and violation of reason in religious matters, is merely resolving with conscious sophistry a question for which he feels no great concern (97), wherever it appears, such an attitude nearly always implies a neglect or denigration of such purely intellectual disciplines as mathematics, since on the one hand they do not make direct reference to naturally existing things, and for Aristotelianism even where they are apparently applicable in that field, they are of uncertain validity, and on the other hand being merely rational they are a priori denied any part in revealing that form of "truth" which concerns man as a spiritual being. The rehabilitation of mathematics was one of the consequences of a reviving Platonism that resolved this dilemma by offering a system in which such doctrines as the eternity of the world, and the soul's existence only as the "form" of the body, did not figure as inescapable and necessary conclusions of the reason, which on other grounds had to be adjudged false. From the unity of the world followed the essential unity of Nature, Reason and Faith. Final truth could be reached in any of these spheres, for to attain it represented a need and its discovery a natural activity of man and in Berkeley's expression of fundamentally the same position as this of Renaissance Platonism, "we should believe that God has dealt more bountifully with the sons of man, than to give them a strong desire for that knowledge, which he had placed quite out of their reach....Providence..., whatever appetites it may have implanted in the creatures, doth usually furnish 'em with such means as, if rightly made use of, will not fail to satisfie them."(98) Reason could be trusted to the uttermost (its detailed relations with Nature and Faith will be discussed later), and the most abstract conclusions that could be established in mathematics could be regarded as being, potentially, of the gravest import.