assimilate what is proper for them, and reject what is hurtful; or when a sponge attracts water, and expels air, etc.; for in all cases, no one body placed near to another can change that other, or be changed by it, unless a reciprocal perception precede the operation. A body always perceives the passages by which it insinuates; feels the impulse of another body, where it yields thereto; perceives the removal of any body that withheld it, and thereupon recovers itself; perceives the separation of its continuity, and for a time resists it; in fine, perception is diffused through all nature. But air has such an acute perception of heat and cold, as far exceeds the human touch, which yet passes for the measure of heat and cold. This doctrine, therefore, has two defects: one, in that men have generally passed it over untouched, though a noble subject; the other, that they who did attend to it have gone too far, attributed sense to all bodies, and made it almost a sin to pluck a twig from a tree, lest the tree should groan, like Polydorus in Virgil. But they ought carefully to have searched after the difference between perception and sense; not only in comparing sensible with insensible things, in the entire bodies thereof, as those of plants and animals, but also to have observed in the sensible body itself, what should be the cause that so many actions are performed without any sense at all. Why the aliments are digested and discharged, the humors and juices carried up and down in the body; why the heart and pulse beat; why the viscera act as so many workshops, and each performs its respective office; yet all this, and much more, be done without sense. But men have not yet sufficiently found of what nature the action of sense is, and what kind of body, what continuance, what repetitions of the impression are required to cause pain or pleasure. Lastly, they seem totally ignorant of the difference between simple perception and sense, and how far perception may be caused without sense. Nor is this a

8 Virg. Æneid, iii.

controversy about words, but a matter of great importance. Wherefore let this doctrine be better examined, as a thing of capital, and very extensive use: for the ignorance of some ancient philosophers in this point, so far obscured the light of reason, that they thought there was a soul indifferently infused into all bodies; nor did they conceive how motion of election could be caused without sense, or sense exist without a soul.

That the form of light should not have been duly inquired into, appears a strange oversight, especially as men have bestowed so much pains upon perspective: for neither has this art, nor others afforded any valuable discovery in the subject of light. Its radiations, indeed, are treated, but not its origin; and the ranking of perspective with mathematics has produced this defect, with others of the like nature, because philosophy is thus deserted too soon. Again, the doctrine of light, and the causes thereof, have been almost superstitiously treated in physics, as a subject of a middle nature, between natural and divine; whence certain. Platonists would have light prior to matter itself: for they vainly imagined that space was first filled with light, and afterward with body; but the Scriptures plainly say, that the mass of heaven and earth was dark before the creation of light. And as for what is physically delivered upon this subject, and according to sense, it presently descends to radiations, so that very little philosophical inquiry is extant about it. And men ought here to lower their contemplations a little, and inquire into the properties common to all lucid bodies, as this relates to the form of light; how immensely soever the bodies concerned may differ in dignity, as the sun does from rotten wood, or putrefied fish. We should likewise inquire the cause why some things take fire, and when heated throw out light, and others not. Iron, metal, stones, glass, wood, oil, tallow, by fire yield either a flame, or grow red-hot. But water and air, exposed to the most intense heat they are capable of, afford no light, nor so much as shine. That it is not the property of fire

alone to give light; and that water and air are not utter enemies thereto, appear from the dashing of salt water in a dark night, and a hot season, when the small drops of the water, struck off by the motion of the oars in rowing, seem sparkling and luminous. We have the same appearance in the agitated froth of the sea, called sea-lungs. And, indeed, it should be inquired what affinity flame and ignited bodies have with glow-worms, the Luciola, the Indian fly, which casts a light over a whole room; the eyes of certain creatures in the dark; loaf-sugar in scraping or breaking; the sweat of a horse hard ridden, etc. Men have understood so little of this matter, that most imagine the sparks, struck between a flint and steel, to be air in attrition. But since the air ignites not with heat, yet apparently conceives light, whence owls, cats, and many other creatures see in the night (for there is no vision without light), there must be a native light in air; which, though weak and feeble, is proportioned to the visual organs of such creatures, so as to suffice them for sight. The error, as in most other cases, lies here, that men have not deduced the common forms of things from particular instances, which is what we make the proper business of metaphysics. Therefore let inquiry be made into the form and origins of light; and, in the meantime, we set it down as deficient. And so much for the doctrine of the substance of the soul, both rational and sensitive, with its faculties, and the appendages of this doctrine.

FIFTH BOOK

CHAPTER 1

Division of the Use and Objects of the Faculties of the Soul into Logic and Ethics. Division of Logic into the Arts of Invention, Judgment,

T

Memory and Tradition.

HE doctrine of the human understanding, and of the human will, excellent king, are like twins; for the purity of illumination, and the freedom of will, began and fell together: nor is there in the universe so intimate a sympathy, as that between truth and goodness. The more shame for men of learning, if in knowledge they are like the winged angels, but in affections like the crawling serpents, having their minds indeed like a mirror; but a mirror foully spotted.

The doctrine of the use and objects of the mental facul ties has two parts, well known and generally received; viz., logic and ethics. Logic treats of the understanding and reason, and ethics of the will, appetite, and affections; the one producing resolutions, the other actions. The imaginations, indeed, on both sides, performs the office of agent, or ambassador, and assists alike in the judicial and ministerial capacity. Sense commits all sorts of notions to the imagination, and the reason afterward judges of them. In like manner reason transmits select and approved notions to the imagination before the decree is executed: for imagination always precedes and excites voluntary motion, and is therefore a common instrument both to the reason and the will, only it has two faces: that turned toward reason bearing the effigy of truth; but that toward action the effigy of goodness: yet they are faces:

But the imagination is more than a mere messenger; as being invested with, or, at least, usurping no small authority, besides delivering the message. Thus, Aristotle well observes, that the mind has the same command over the body, as the master over the slave; but reason over the imagination, the same that a magistrate has over a free citizen, who may come to rule in his turn. For in matters of faith and religion, the imagination mounts above reason. Not that divine illumination is seated in the imagination, but, as in divine virtues, grace makes use of the motions of the will; so in illumination it makes use of the motions of the imagination; whence religion solicits access to the mind, by similitudes, types, parables, dreams, and visions. Again, the imagination has a considerable sway in persuasion, insinuated by the power of eloquence: for when the mind is soothed, enraged, or any way drawn aside by the artifice of speech, all this is done by raising the imagination; which, now growing unruly, not only insults over, but, in a manner, offers violence to reason, partly by blinding, partly by incensing it. Yet there appears no cause why we should quit our former division: for in general, the imagination does not make the sciences; since even poetry, which has been always attributed to the imagina. tion, should be esteemed rather a play of wit than a science. As for the power of the imagination in natural things, we have already ranged it under the doctrine of the soul; and for its affinity with rhetoric, we refer it to the art of. rhetoric.

This part of human philosophy which regards logic, is disagreeable to the taste of many, as appearing to them no other than a net, and a snare of thorny subtilty. For as knowledge is justly called the food of the mind, so in the desire and choice of this food, most men have the appetite of the Israelites in the wilderness, who, weary of manna, as a thin though celestial diet, would have gladly returned to

• Aristotle's Politics, i. 5, 6.