Chapter III (4)
Renaissance Francis Bacon EnglishDivision of the Invention of Arguments into Promptuary, or Places of Preparation, and Topical, or Places of Suggestion. The Division of Topics into General and Particular. An Example of Particular Topics afforded by an Inquiry into the Nature of the Qualities of Light and Heavy
THE invention of arguments is not properly an invention; for to invent, is to discover things unknown before, and not to recollect or admit such as are known already. The office and use of this kind of invention seems to be no more than dexterously to draw out from the stock of knowledge laid up in the mind such things as make to the present purpose; for one who knows little or nothing of a subject proposed, has no use of topics or places of invention, while he who is provided of suitable matter, will find and produce arguments, without the help of art and such places of invention, though not so readily and commodiously; whence this kind of invention is rather a bare calling to memory, or a suggestion with application, than a real invention. But since the term is already received, it may still be called invention, as the hunting in a park may be called hunting no less than that in the open field. But not to insist upon the word, the scope and the end of the thing itself, is a quick and ready use of our thoughts, rather than any enlargement or increase of them.
There are two methods of procuring a stock of matter for discourse; viz., 1, either by marking out, and indicating the parts wherein a thing is to be searched after, which is what we call the topical way; or 2, by laying up arguments for use, that were composed beforehand, relating to such things as frequently happen and come in dispute; and this we call the promptuary way: but the latter can scarce be called a part of science, as consisting rather in diligence than any artificial learning. Aristotle on this head ingeniously derides the Sophists of his time, saying, they acted like a professed shoemaker, who did not teach the art of shoemaking, but set out a large stock of shoes, of different shapes and sizes. But it might be replied, that the shoemaker who should have no shoes in his shop, and only make them as they were bespoke, would find few customers. Our Saviour speaks far otherwise of divine knowledge, saying, “Therefore every scribe which is instructed into the kingdom of heaven, is like unto a man that is an householder, which brings forth out of his treasure things new and old.”
We find also that the ancient rhetoricians gave it in precept to the orators to be always provided of various commonplaces, ready furnished and illustrated with arguments on both sides; as for the intention of the law against the words of the law; for the truth of arguments against testimonies, and vice versa. And Cicero himself, being taught by long experience, roundly asserts, that a diligent and experienced orator should have such things as come into dispute, ready labored and prepared, so as that in pleading there should be no necessity of introducing anything new or occasional, except new names, and some particular circumstances. But as the first opening of the cause has a great effect in preparing the minds of the audience, the exactness of Demosthenes judged it proper to compose beforehand, and have in readiness, several introductions to harangues and speeches; and these examples and authorities may justly overrule the opinion of Aristotle, who would have us change a whole wardrobe for a pair of shears. This promptuary method, therefore, should not be omitted; but as it relates as well to rhetoric as to logic, we shall here touch it but slightly; designing to consider it more fully under rhetoric.
We divide topical inventions into general and particular. The general is so copiously and diligently treated in the common logics, that we need not dwell upon its explanation: we only observe by the way, that this topical method is not only used in argumentation and close conference, but also in contemplation, when we meditate or revolve anything alone. Nor is its office only confined to the suggesting or admonishing us of what should be affirmed or asserted, but also what we should examine or question; a prudent questioning being a kind of half-knowledge; for, as Plato justly observes, a searcher must have some general notion of the thing he searches after, otherwise he could never know it when he had found it; and, therefore, the more comprehensive and sure our anticipation is, the more direct and short will be the investigation. And hence the same topics which conduce to the close examining into our own understandings, and collecting the notices there treasured up, are likewise assistant in drawing forth our knowledge. Thus, if a person, skilful in the point under question, were at hand, as we might prudently and advantageously consult him upon it; in like manner, we may usefully select and turn over authors and books, to instruct and inform ourselves about those things we are in quest of.
But the particular topical invention is much more conducive to the same purposes, and to be esteemed a highly fertile thing. Some writers have lately mentioned it, but it is by no means treated according to its extent and merit. Not to mention the error and haughtiness which have too long reigned in the schools, and their pursuing with infinite subtilty such things as are obvious, without once touching upon those that lie remote, we receive this topical invention as an extremely useful thing, that affords certain heads of inquiry and investigation appropriated to particular subjects and sciences. These places are certain mixtures of logic and the peculiar matter of each science. It is an idle thing, and shows a narrow mind, to think that the art of discovering the sciences may be invented and proposed in perfection from the beginning, so as to be afterward only exercised and brought into use; for men should be made sensible that the solid and real arts of invention grow up and increase along with inventions themselves; so that when any one first comes to the thorough examination of a science, he should have some useful rules of discovery; but after he has made a considerable progress in the science itself, he may, and ought, to find out new rules of invention, the better to lead him still further. The way here is like walking on a flat, where, after we have gone some length, we not only approach nearer the end of our journey, but also have a clearer view of what remains to be gone of it; so in the sciences, every step of the way, as it leaves some things behind, also gives us a nearer prospect of those that remain: and as we report this particular topical invention deficient, we think proper to give an example of it in the subject of gravity and levity.
Let inquiries be made what kind of bodies are susceptible of the motion of gravity; what of levity; and if there be any of a middle or neutral nature.
After the simple inquiry of gravity and levity, proceed to a comparative inquiry; viz., which heavy bodies weigh more, and which less, in the same dimensions; and of like ones, which mount upward the swifter, and which the slower.
Inquire what effect the quantity of the body has in the motion of gravity. This at first sight may appear a needless inquiry, because motion may seem proportionable to quantity; but the case is otherwise. For although in scales quantity is equal to the gravity, yet where there is a small resistance, as in the falling of bodies through the air, quantity has but little force to quicken the descent; but twenty pounds of lead, and a single pound, fall nearly in the same time.
Inquire whether the quantity of a body may be so increased as that the motion of gravity shall be entirely lost, as in the globe of the earth, which hangs pendulous without falling. Query, therefore, whether other masses may be so large as to sustain themselves? For that bodies should move to the centre of the earth is a fiction; and every mass of matter has an aversion to local motion, till this be overcome by some stronger impulse.
Inquire into the effects and nature of resisting mediums, as to their influencing the motion of gravity; for a falling body either penetrates and cuts through the body it meets in its way, or else is stopped by it. If it pass through, there is a penetration, either with a small resistance, as in air, or with a greater, as in water. If it be stopped, it is stopped by an unequal resistance, where there is a preponderancy, as when wood is laid upon wax; or by an equal resistance, as when water is laid upon water, or wood upon wood of the same kind; which is what the schools pretend, when they idly imagine that bodies do not gravitate in their own places. And all these circumstances alter the motion of gravity; for heavy bodies move after one way in the balance, and after another in falling: and, which may seem strange, after one way in a balance suspended in the air, and after another in a balance plunged in water; after one way in falling through water, and after another when floating upon it.
Inquire into the effects of the figure of the descending body, in directing the motion of gravity: suppose of a figure broad and thin, cubical, oblong, round, pyramidal, etc.; and how bodies turn themselves while they remain in the same position as when first let go.
Inquire into the effects of the continuation and progression of the fall or descent itself, as to the acquiring a greater impulse or velocity, and in what proportion and to what length this velocity is increased; for the ancients, upon slender consideration, imagined that this motion, being natural, was always upon the increase.
Inquire into the effects of distance, or the near approach of a body descending to the earth, so as to fall swifter, slower, or not at all, supposing it were to be out of the earth’s sphere of activity, according to Gilbert’s opinion; as also the effects of plunging the falling body deeper into the earth, or placing it nearer the surface; for this also varies the motion, as is manifest to those who work in mines.
Inquire into the effects of the difference of bodies, through which the motion of gravity is diffused and communicated; and whether it is equally communicated through soft and porous bodies, as through hard and solid ones. Thus if the beam of a scale were one half of wood, and the other half of silver, yet of the same weight; inquire whether this would not make an alteration in the scales: and again, whether metal laid upon wool, or a blown bladder, would weigh the same as in the naked scale.
Inquire into the effects of the distance of a body from the point of suspension in the communication of the motion of gravity; that is, into the earlier or later perception of its inclination or depression: as in scales, where one side of the beam is longer, though of the same weight with the other, whether this inclines the beam; or in siphons, where the longer leg will draw the water, though the shorter, being made wider, contains a greater weight of water.
Inquire into the effects of intermixing or coupling a light body and a heavy one, for lessening the gravity of bodies; as in the weight of creatures alive and dead.
Inquire into the ascents and descents of the lighter and heavier parts of one entire body: whence curious separations are often made, as in the separation of wine and water, the rising of cream from milk, etc.
Inquire what is the line and direction of the motion of gravity, and how far it respects the earth’s centre, that is, the mass of the earth; or the centre of its own body, that is, the appetite of its parts. For these centres are properly supposed in demonstrations, but are otherwise unserviceable in nature.
Inquire into the comparative motion of gravity, with other motions, or to what motions it yields, and what it exceeds. Thus in the motion they call violent, the motion of gravity is withheld for a time; and so when a large weight of iron is raised by a little loadstone, the motion of gravity gives way to the motion of sympathy.
Inquire concerning the motion of the air, whether it rises upward, or be as it were neutral, which is not easy to be discovered without some accurate experiments; for the rising up of air at the bottom of water, rather proceeds from a resistance of the water, than the motion of the air, since the same also happens in wood. But air mixed with air makes no discovery; for air in air may seem as light, as water in water seems heavy: but in bubbles, which are air surrounded with a thin pellicle of water, it stands still for a time.
Let the bounds of levity be inquired after; for though men make the centre of the earth the centre of gravity, they will perhaps hardly make the ultimate convexity of the heavens the boundary of levity; but rather, perhaps, as heavy bodies seem to be carried so far, that they rest, and grow as it were immovable; light bodies are carried so far, that they begin a rotation or circular motion.
Inquire the cause why vapors and effluvia are carried so high as that called the middle region of the air, since the matter of them is somewhat gross, and the rays of the sun cease alternately by night.
Inquire into the tendency of flame upward, which is the more abstruse, because flame perishes every moment, unless perhaps in the midst of larger flames; for flames broken from their continuity are of small duration.
Inquire into the motion and activity of heat upward; as when heat in ignited iron sooner creeps upward than downward. And thus much by way of example of our particular topical inquiry. We must, for a conclusion, admonish mankind to alter their particular topics in such manner, as after some considerable progress made in the inquiry, to raise topic after topic, if they desire to ascend to the pinnacle of the sciences. For my own part, I attribute so much to these particular topics, that I design a particular work upon their use, in the more eminent and obscure subjects of nature; for we are masters of questions, though not of things. And here we close the subject of invention.