[548] The part of natural philosophy which is speculative and theoretical can be divided into physics proper, and metaphysics. In this division, it should be noted that I am using the word ‘metaphysics’ in a sense which is different from ordinary received usage. This seems the right place to point out my general policy about the use of words. My policy is that, especially when I use a metaphysical term, if my concepts and notions are new, and depart from what is currently accepted, I am scrupulous about retaining traditional terminology. I hope that in the future, the very regularity of nature, and its clear explanation which I am trying to add, will free us from misunderstandings of the words we use. However that may be, it is my firm intention to depart as little as possible from the doctrines and terminology of the ancients, as far as this can be done without detriment to the truth or the sciences.

So let us return to the meaning of the word ‘metaphysics’ in my sense. It is obvious from what I have said above, that I make a distinction between first philosophy and metaphysics, even though they have hitherto been taken as the same thing. I have made first philosophy the parent shared by all the sciences, [550] and metaphysics a part of natural philosophy. I have assigned to first philosophy the axioms which are indiscriminately common to the sciences. I have even attributed to it relative and accidental states of entities (which I have called ‘transcendent’), such as ‘many’, ‘few’, ‘same’, ‘different’, ‘possible’, ‘impossible’, and others of the same kind — only being careful to deal with them as a physicist rather than as a logician. I have assigned questions about God, the one, the good, angels, and spirits to natural theology. So, it might well be asked, what is left to metaphysics? Certainly nothing supernatural, but by far the most important part of nature itself. Undoubtedly, and without any harm to the truth, I can go along this far with the opinion of the ancients, and reply that physics deals with things which are deeply immersed in matter and are subject to change, whereas metaphysics deals with things which are more abstract and unchanging. Again, physics presupposes in nature only existence, motion, and natural necessity; whereas metaphysics also presupposes mind and ideas. This probably amounts to the same as what I am about to say; but I shall explain it clearly and in everyday terms, without high-blown language. I have divided natural philosophy into the discovery of causes and the production of effects; and I have classified the discovery of causes as belonging to theory, which I have divided into physics and metaphysics. Therefore it follows that the real difference between them lies in the nature of the causes they investigate. So without any obscurity or beating about the bush, physics inquires into efficient and material causes, and metaphysics enquires into formal and final causes.

So physics covers the aspects of causes which are vague and uncertain, and which vary from subject to subject. It does not pursue the constancy of causes.

But again, I divide diffuse physics, or the physics of the variety of things, into two branches: concrete physics, and abstract physics; or the physics of created things, and the physics of natures. The one (to use terms drawn from logic) is concerned with substances, together with all their variety of accidents; and the other is concerned with accidents, together with all the variety of substances they inhere in. For example, if we are researching into lions or oak trees, they support very many different accidents; on the other hand, if we are researching into heat or heaviness, they inhere in many distinct substances. But since the whole of physics lies between natural history and metaphysics, the first part (if you consider it correctly) is closer to natural history, and the latter part is closer to metaphysics.

But concrete physics is subject to the same division as natural history; so it is either about the heavens, or about the atmosphere, or about the sphere of land and sea, or about the ‘major colleges’, as the elements are called, or about the ‘minor colleges’, or species; and also about monstrous births, and about mechanics. In all these, natural history researches into and reports on the facts, and physics does the same with their causes — but note that here I mean their variable causes, namely their material and efficient causes.

Among these divisions of physics, the most defective and incomplete is the one which researches into the heavens, even though [552] it should be the closest concern of human beings, because of the nobility of the subject. Astronomy is solidly based on the phenomena; but it is a lowly subject, and also far from complete; and in most respects, astrology does not have any foundation at all. What astronomy offers the human intellect is like the fake sacrifice which Prometheus once offered to Jupiter. Instead of a genuine ox, Prometheus brought along the skin of a large and beautiful ox stuffed with straw, leaves, and twigs. Similarly, astronomy shows us the outsides of the heavenly bodies (I mean the number, positions, motions, and circuits of the stars) — as it were, the skin of the sky, beautiful, and skilfully organised into systems. But it has no insides (i.e. a physical rationale) from which a theory could be derived by means of additional astronomical hypotheses.

And by ‘theory’, I do not mean simply one which is consistent with the phenomena, since innumerable such theories can be put together by people who are clever enough. I mean a theory which represents substance, motion, and celestial influence as they really are. It is quite a time now since we abandoned the theories of the motive power of the Prime Mover and of the solidity of the firmament (as if the stars were attached to their spheres like nails in the ceiling). Almost as bad are the claims that the poles of the zodiac and of the universe are different; that there is a Second Mover which acts in the opposite direction of the motive power of the Prime Mover; that everything in the heavens moves in perfect circles; that there are eccentric motions and epicycles by which perfectly circular motions are kept constant; that there is no change or force above the Moon; and so on. It is the absurdity of these assumptions which has driven people to believe in the daily rotation of the Earth — though it is obvious to me that this is completely false.

There is hardly anyone who has investigated the physical causes of the substance of heavenly bodies (both stellar and interstellar); the relative speeds of heavenly bodies; the different motive forces acting on one and the same planet; the sequence of motions from East to West, and vice versa; the progressions, stations, and retrogressions of the planets; the rise and fall of motions in apogee and perigee; oblique motions, such as the spirals winding and unwinding towards the tropics, or the twisting motions called ‘dragons’; why the poles of rotations are in this part of the sky rather than another; and why some planets are at a fixed distance from the sun. As I say, this sort of investigation has hardly been attempted, [553] and people have confined their efforts to mathematical observations and proofs. The results show how ingeniously everything can be made to fit together consistently, but not how things really are in nature. We are presented with motions only as they appear, and with an arbitrary fiction about the machinery which produces them, but not with their genuine causes or the truth as it really is.

This is why astronomy (as it now is) has quite understandably been classified as one of the mathematical arts; but at the expense of its dignity, since it should instead constitute the most noble part of physics (if it wants to defend its proper territory). We must reject the fictitious divorce between the regions above and below the moon, and have a proper understanding of the most universal appetites and passions of matter, which apply to both regions and permeate the whole universe. Only then can we acquire clear information about things in the sky on the basis of what we can see from earth. Conversely, from what happens in the sky, we can learn a lot about motions on earth, of which we are now ignorant — not so much because of astrological influences, but more because of the passions they have in common. This is why I have declared that the physical part of astronomy [554] does not yet exist as a science. I shall call it ‘live astronomy’, by analogy with the difference between a live ox, and Prometheus’s stuffed one, which was only an ox in outward appearance.

Astrology is so crammed with superstition, that it is almost impossible to find anything sound in it. Yet I believe it should be corrected rather than completely rejected. . . . .I accept astrology as a part of physics; but I attribute to it no more than is allowed by reason and what is obvious to the senses, after the superstitions and lies have been eliminated. . . . .

[555] So it is more relevant for me to say what we should ultimately retain with our approval in astrology, and what, among those aspects we approve of, has yet to be achieved. It is this last (namely what has yet to be achieved) which I set out to deal with here; besides, as I have often said, I have no time for criticising what has been done. I believe that, of the generally accepted astrological doctrines, that of revolutions is certainly sounder than the rest. But it would be best if I laid down certain rules as a standard for weighing and assessing astrological doctrines, to see which should be retained as useful, and which should be rejected as vacuous. First, as I just said, let us keep the major revolutions, but goodbye to the lesser ones of horoscopes and houses. The former are like huge cannons, which can project their impact over a long distance; whereas the latter are like little bows, which cannot send their powers over any distance. Second, heavenly bodies cannot influence every type of body, but only the more rarefied ones, like the humours, air, and spirit. Nevertheless, there is one exception, namely the effect of the heat of the sun and stars, which can undoubtedly reach metals and many other things under the ground. Third, any influence of the heavenly bodies is more on collections of things [556] than on individuals. However, some individuals are also influenced indirectly, when they are the most susceptible individuals of the same species, and made of softer wax, so to speak — as when an airborne infection gets a hold on people whose bodies have the least resistance, and passes stronger ones by. The fourth is quite similar to the third, namely that heavenly influences are never instantaneous or confined to a precise place, but they have their effect by diffusion over wide areas. Consequently, predictions of the character of a whole year could be true; but predictions about individual days would rightly be considered vacuous. The last (which has also always been accepted by the more prudent astrologers) is that there is no fatal necessity in the stars, but that they incline rather than compel. I shall add one more thing, which will make it clear that I am on the side of astrology, provided it is reformed. This is that I am certain that the heavenly bodies contain various influences other than heat and light, and that they operate in accordance with the rules I have just laid down, and in no other way. But these influences lie hidden in the depths of physics, and they would require much more extensive treatment. So after careful consideration of what I have said, I have decided to include an astrology consistent with my principles as one of the sciences yet to be developed. And just as I called an astronomy which is founded on physical causes ‘live astronomy,’ so I shall call an astrology which is governed by my rules ‘sound astrology.’ . . . .

There are two distinct kinds of appetites and motions. Motions are either simple, which include the source of all natural actions, but modified by the schematisms of matter; or composite or produced, which the established philosophy starts out from, since it has too restricted a notion of natural body. However, composite motions (such as coming to be, ceasing to be, and the rest) should be considered as the products or totals of simple motions, rather than as primary motions in their own right. Simple motions are the motion of antitypy, which is usually called the motion which prevents something from penetrating the dimensions of a body. . . .

[561] Abstract physics consists of no more than the schematisms of matter, simple motions, totals or aggregates of motions, and measures of motion. Voluntary motion in animals; the motion which occurs in the actions of the senses; the motion of the imagination, appetite, and will; and the motion of the mind, of decision, and of the objects of the intellect — these I allocate to their own disciplines. However, I must repeat my warning that everything I have spoken about here should be dealt with as part of physics only in so far as their material and efficient causes are in question. They are handled again in metaphysics as far as their formal and final causes are concerned.. . . .

[564] Nevertheless, I must advise that it should be done in separate sections, so that each philosophical system is put together on its own, and running from beginning to end — not excerpts bundled together under topics, as Plutarch did. Every philosophical system supports itself as a whole, and its individual doctrines strengthen and illuminate each other. But when they are taken out of context, they sound strange and difficult to believe. When I read what Nero or Claudius did in Tacitus, it all seems quite plausible, because Tacitus puts their actions in the context of the times, the people, and the circumstances. But when I read about the same things in Suetonius Tranquillus, they seem totally fabulous and incredible, because virtually nothing is presented in chronological order, but under topics and subject headings. Much the same is the case with philosophical systems, when expounded as a whole, or when chopped up into separate little extracts.

Nor would I exclude modern theories and doctrines from this Digest of Philosophical Theses — for example, the philosophy of Theophrastus Paracelsus, which has been eloquently condensed into a consistent system by the Danish philosopher Severinus; or that of Telesio of Cosenza, who revived the philosophy of Parmenides, and turned the weapons of the Aristotelians against themselves; or that of Patrizi of Venice, who distilled the essence of Platonism; or of our fellow-countryman Gilbert, who reinstated the doctrines of Philolaus; or of anyone else, provided they are worthy. But since their works are available complete, only summaries need to be added to the rest.

This is all I have to say about physics and its appendices.

Here is an analogy. It would not be easy, and it would be quite pointless, to investigate the form of the sound which constitutes some given word, since the composition and transposition of letters results in an infinity of words; but it is understandable, and indeed quite easy, to investigate the form of the sound which expresses a simple letter (that is, what positions and movements of the organs of speech produce it); and once the forms of letters are known, they lead us directly to the forms of words. In exactly the same way, [566] it is a waste of time inquiring into the form of a lion, of an oak, or of gold — or even the form of water or of air. Instead, one should inquire into the form of the dense and the rarefied; the hot and the cold; the tangible and the spiritual; the volatile and the fixed — and other such schematisms and motions, most of which I listed when saying what should be dealt with in physics, and which I have usually called ‘forms of the first order’. Like the letters of the alphabet, there are not so many of them; and yet they are the source and material for the essences and forms of all substances. This is just what I am trying to do, and it is what constitutes and defines the part of metaphysics which I am now discussing.

Nor do they prevent physics from considering the same natures as well (as I have said), but only is so far as they are variable causes. For example, if we are enquiring into the cause of whiteness in snow or foam, the right answer is that it is a subtle mixture of air and water. But this is far from being the form of whiteness, since air similarly produces whiteness if it is also mixed with powdered glass or crystal, no less than if it is mixed with water. But it is only the efficient cause, which is nothing other than the carrier of the formal cause. But if the question is being asked in metaphysics, you will find something like the following: whiteness consists in two transparent bodies mixed together in such a way that there is a simple or equal ratio between the parts by virtue of which they are visible.

I find that this part of metaphysics has not yet been developed as a science. This is not surprising, since even a hundred years of research using the methods which have been used up till now would never result in the forms of things. The root of this evil (as of all evils) is people’s habit of letting their thoughts stray too quickly and too far from experience and individual things, in favour of abstractions; and they have given themselves over entirely to their own meditations, and arguments with others.

The second part of metaphysics is the inquiry into final causes. [569] I do not class it as a study which has been neglected, but misplaced, since it has usually been treated as part of physics instead of metaphysics. To me, it would not matter so much if it were merely a question of order, since order affects the clarification rather than the substance of the sciences. But this inversion of order has given rise to a significant defect, which has been a major disaster for philosophy. The treating of final causes in physics has replaced and eliminated the study of physical causes. To the huge detriment of the sciences, it has meant that people have accepted showy but shadowy causes, and have failed to make the effort to push forward the investigation of real and genuinely physical causes.

I find that this been done, not only by Plato, who was always firmly anchored to this shore, but also by Aristotle, Galen, and others, who very often ran aground on these shoals. Although it is perfectly acceptable in metaphysics, it is certain not acceptable in physics to appeal to causes such as the following: ‘the eyelids and eyelashes function as a hedge or fence in order to protect the eyes;’ or ‘the thickness of the hide of animals is in order to keep out heat and cold;’ or ‘nature uses bones as columns and beams in order to support the fabric of the body;’ or ‘trees sprout leaves so that their fruits will suffer less damage from the sun and the wind;’ or ‘clouds are formed in the sky so that they can water the soil with rain;’ or ‘the earth was made thick and solid so that animals could stand and live on it;’ and other such. Indeed, as I was beginning to say, such ways of speaking are like the mythical fish called the ‘remora’, which sticks to ships and stops them from moving; in the same way, they prevent the sciences from setting their sails, going in the right direction, and advancing further. Long ago they brought it about that research into physical causes was neglected and passed over in silence.

Nor does this fact call divine providence into doubt, or lessen it in any way, but rather confirms it, and makes it all the greater. In civil affairs, you would be admired for your great political skill if you could use other people’s efforts to achieve your own purposes and desires, but without letting them known your plans (so that they do what you want, but without realising that this is what they are doing). This is a much greater skill than if you communicate your plans to those responsible for carrying out your will. In the same way, the wisdom of God shines much more wonderfully when nature does one thing, and providence entices another, than if the marks of providence were impressed on each natural form and motion individually.

That is to say, after Aristotle had impregnated nature with final causes, and made claims like ‘nature does nothing in vain, and always does what it wants (provided there are no obstructions),’ and many others to the same effect, [571] there was no further need of God. But when Democritus and Epicurus preached their atoms, they were tolerated just so far by quite a few intelligent people. However, they were ridiculed by everybody when they said that the whole structure of the universe was formed by their random collisions. So much so, that far from physical causes leading people away from God and providence, instead, the philosophers who made it their business to discover them found no solution to the problem without finally resorting to God and providence.

This is all I have to say about metaphysics. I do not deny that the part which is concerned with final causes has been dealt with in books on physics as well as on metaphysics — in the latter correctly, but in the former incorrectly, because of the disadvantages this gives rise to.

I shall similarly divide the practical aspect of nature into two parts. This is necessary, because this division depends on the previous division of speculative philosophy. Physics and research into efficient and material causes produces mechanics; whereas metaphysics and research into forms produces magic. Research into final causes is sterile, and it gives birth to nothing, since it is, as it were, a virgin consecrated to God.

I am not overlooking the fact that, [572] as often as not, even mechanics is merely empirical and practical, without any dependence on physics. But in so far as it is done in this way, I have kept it separate from natural philosophy, and classified it as part of natural history. Here I am talking only about the mechanics which is combined with physical causes. However, there is an intermediate type of mechanics, which is not purely practical, but does not make contact with physics as such. All practical discoveries which humans have made, have either happened by chance, and subsequently been handed down by example; or they have been deliberately sought after. Things which have been discovered intentionally have either been unearthed in the light of causes and axioms, or they have emerged as the result of extending what has already been discovered, or of applying it to a different area, or of making new combinations. This is more the outcome of wit and wisdom than of philosophy. I by no means despise this part of the practical study of nature, and a little later I shall discuss it briefly, when I deal with ‘experience informed by learning’ under ‘logic’.

As for natural magic, (a term which crops up in many people’s books), it embraces various credulous and superstitious traditions and alleged experiences about the ‘sympathies’ and ‘antipathies’ of things, and about ‘occult’ and ‘specific’ properties. These are combined with observations which are mostly trivial, and which are to be wondered at more for the ingenuity with which the truth is concealed and masked, than for the thing itself. Indeed, you would not be wrong if you said that, in the case of the truth about nature, this is as far removed from the science we are seeking, as, in the case of historical fact, the legends about Arthur of Britain, or Hugo of Bordeaux, or other such shadowy heroes, are removed from Caesar’s Commentaries. It is obvious that Caesar actually achieved more than the authors of these legends dared invent for their heroes, and he did what he did without their mythical means. A good illustration of this sort of doctrine is the myth of Ixion, who wanted to have sex with Juno, the goddess of power, but in fact had it off with a fleeting cloud, and thus became the father of centaurs and chimeras. In the same way, those who are driven by a mad and ineffectual desire for things which they only think they discern through the fogs and clouds of their imaginations, instead of genuine achievements, will breed nothing but vain hopes, and deformed and monstrous spectres.

The effect of this frivolous and degenerate natural magic [574] on people is similar to that of sleeping pills, which not only send you to sleep, but also give you sweet and pleasant dreams while you are asleep. First it sends the human intellect into a stupor by singing a lullaby about specific properties, and occult virtues which are sent down as from heaven, and are to be known only through the whisperings of a secret tradition. This means that people are no longer aroused and stay awake to search out and track down genuine causes, but merely accept lazy and credulous opinions like these. Then it sneaks in innumerable lies, which are pleasing and just what people most want to believe — like dreams.

Similarly, it is difficult to believe that old age can be postponed, or that we can become younger. But someone might be able prolong life, or partly restore the vigour of youth, by diets, baths, ointments, special medicines, appropriate exercise, and the such like, based on a thorough knowledge of the nature of desiccation, and of the attrition of the solid parts of the body caused by the spirits; and on an understanding of the nature of digestion and nutrition, whether functioning well or badly; and also on being aware of the nature of the spirits, which are as it were the vital flames of the body, some of which tend to burn it up, and some of which tend to repair it. This is far more likely to achieve the desired outcome than tiny drops or shavings of some precious balm or quintessence.

Again, not everyone immediately or readily agrees that our fates can be read from the stars; and you might say that it is ridiculous to claim that the hour of one’s birth determines all one’s fortune in life, since the precise time depends on a range of natural contingencies; or that there is an auspicious time for conducting a specific piece of research.

However, the human race is so [575] lacking in self-control, and so immoderate, that people not only promise themselves the impossible, but they are confident that they can attain the most difficult achievements without any trouble or sweat, as if they were on holiday. This is all I have to say about magic. I have cleared the word of its pejorative connotations, and I have distinguished between the genuine kind, and that which is false and unworthy. . . .