Chapter V

Motion is the prime and fundamental idea in Hobbes’s philosophy. It runs through all his writings, and enters into almost every explanation which he has given of anything. He treated sense and sensation at length as a part of physics in his “Elements of Philosophy,” and in almost all his different works he touches more or less on this subject. His psychology has the merit of being pretty distinct; as sensation and thought both proceed from motion, their explanation is not a difficult matter. Concerning sense, he says: “I have shown that no motion is generated but by a body contagious and moved: whence it is manifest that the immediate cause of sense or perception consists in this, that the first organ of sense is touched or pressed. For when the uttermost part of the organ is pressed, it no sooner yields but the part next within it is pressed also; and, in this manner, the pressure or motion is propagated through all the parts of the organ to the innermost. And thus, also, the pressure of the uttermost part proceeds from the pressure of some remote body, and so continually till we come to that from which, as from its fountain, we derive the phantasm or idea that is made in us by our sense. And this, whatever it be, is what we commonly call the object. Sense, therefore, is some internal motion in the sentient, generated by some internal motion of the parts of the object, and propagated through all the media to the innermost part of the organ.... Moreover, I have shown that all resistance is endeavour opposite to another endeavour, that is to say, reaction...; so that when that endeavour inwards is the last action in the act of sense, then from the reaction, however little the duration of it be, a phantasm or idea has its being; which, by reason that the endeavour is now outwards, does always appear as something placed without the organ.” ... Then we get this definition: “Sense is a phantasm made by the reaction and endeavour outwards in the organ of sense, caused by an endeavour inwards from the object, remaining for some time more or less.” How much importance he attached to motion in the derivation of sensation, ideas, and thought is indicated in the following passages: “Now [that] all mutation or alteration is motion or endeavour (and endeavour also is motion), in the internal parts of the thing that is altered, as has been proved.... Sense, therefore, in the sentient, can be nothing else but motion in some of the internal parts of the sentient, and the parts so moved are parts of the organs of sense.” Again, “the original of life being in the heart, that motion in the sentient, which is propagated to the heart, must necessarily make some alteration or diversion of vital motion, namely, by quickening or slackening, helping or hindering the same. Now, when it helps, it is pleasure; when it hinders, it is pain, trouble, grief, and so on.... Now vital motion is the motion of the blood, perpetually circulating (as has been shown from many infallible signs and marks by Dr. Harvey, the first observer of it) in the veins and arteries. Which motion, when it is hindered by some other motion, made by the action of sensible objects, may be restored again, either by bending or setting straight the parts of the body; which is done when the spirits are carried now into these, now into other nerves, till the pain, as far as is possible, be quite taken away. But if vital motion be helped by motion made by sense, then the parts of the organ will be disposed to guide the spirits in such manner as conduces most to the preservation and augmentation of that motion, by the help of the nerves. And in animal motion this is the very first endeavour, and found even in the embryo; which while it is in the womb, moves its limbs with voluntary motion, for the avoiding of what troubles it, or for the pursuing of what pleases it. And this first endeavour, when it tends towards such things as are known by experience to be pleasant, is called appetite, that is, an approaching; and when it shuns what is troublesome, aversion, or flying from it.”¹ He goes on to associate appetite and will, and shows that the same thing is called both will and appetite. More briefly, he says that all ideas and thought originate from sensation, thus: “The original of them all is that which we call sense, for there is no conception in a man’s mind which has not at first, totally, or by parts, been begotten upon the organs of sense. The rest are derived from that original.” Again, originally, all conceptions proceed from the action of the thing itself, whereof it is the conception: now when the action is present, the conception it produces is also called sense; and the thing by whose action the same is produced, is called the object of the sense.² Hobbes stated the conditions of sensation and perception very well. In order to make them clear, he distinguished the subject and object of sense, the former being the perceiving person, and the latter the thing perceived; and it is more correct to say that we see the sun than that we see the light; because light and colour, heat, sound, and other qualities, are not properly objects, but ideas in the mind. He further stated that there must always be a variety and difference among the objects of perception, and discriminated other points.

¹ _Elements of Philosophy_, Past IV., Chapter XXV., Section 2;
Sections 2, 12, 13.

² _Leviathan_, Part I., Chapter I.; _Human Nature_, Chapter
II., Section 2.

In further explaining his views of mind, he calls imagination “a decaying sense,” by which he means the impressions, images, or ideas of external objects remaining in the mind after the sensations which caused them were past. His exposition of the subject is this:――“That when a thing lies still, unless somewhat else stir it, it will lie still for ever, is a truth that no man doubts of. But that when a thing is in motion, it will eternally be in motion, unless somewhat else stay it, though the reason be the same, namely, that nothing can change itself, is not so easily assented to.” ... Therefore, “when a body is once in motion, it moves, unless something else hinder it, eternally; and whatever hinders it, cannot in an instant, but in time, and by degrees; and as we see in the water, though the wind cease, the waves give not over rolling for a long time after; so also it happens in that motion which is made in the internal parts of a man, then, when he sees, dreams, and so on. For after the object is removed, or the eye shut, we still retain an image of the thing seen, though more obscure than when we see it. And this is it the Latins call imagination, from the image made in seeing.... But the Greeks call it a fancy, which signifies appearance, and is as proper to one sense as to another. Imagination, therefore, is nothing but decaying sense; and is found in men, and in many other living creatures, as well sleeping as waking.

“The decay of sense in men waking is not the decay of the motion made in sense but an obscuring of it, in such manner as the light of the sun obscures the light of the stars.... For as at a great distance of place, that which we look at appears dim and without distinction of the smaller parts, so also, after great distance of time, our imagination of the past is weak, and we lose, for example, of cities we have seen, many particular streets, and of actions, many particular circumstances. This decaying sense, when we would express the thing itself, I mean fancy itself, we call imagination; but when we would express the decay, and signify that the sense is fading, old, and past, it is called memory.” So that imagination and memory are but one thing with different names.¹

¹ _Leviathan_, Part I., Chapter II.; see also _Human Nature_,