THE work entitled ‘The Passions of the Soul’ was written in French during the winter of 1645-6, four years before its author’s death. It was the last work published by Descartes, who, indeed, expressed himself as very unwilling to appear again in print; the publication of the work was probably due to the urgent entreaties of Clerselier, Chanut, and other friends. Baillet, his biographer, says Descartes never published without regretting it, and certainly his publishers did not encourage him to do so, for complaints were constant as to the small sale of his books. The ‘Passions’ was sent to Queen Christina of Sweden, with whom Descartes had carried on a correspondence on the subjects allied to those discussed in this book. The first sketch had been sent to his other royal friend, Princess Elizabeth of Palatine in April, 1646, and she suggested some slight alterations upon it. The manuscript was placed in Clerselier’s hands in August, 1649 and was printed in Amsterdam in the end of November by Louis Elzevir, while Henry le Gras issued it at the same time in Paris. The author was at this period in Sweden, where he died, but he had probably revised the proofs before leaving Holland. He received copies of the book before his death, which was accelerated by the early morning lessons given in the depth of winter to Queen Christina at Stockholm.
E. S. H.
PART FIRST. OF THE PASSIONS IN GENERAL, AND INCIDENTALLY OF THE WHOLE NATURE OF MAN.
ARTICLE I.
That what in respect of a subject is passion, is in some other regard always action.
There is nothing in which the defective nature of the sciences which we have received from the ancients appears more clearly than in what they have written on the passions; for, although this is a matter which has at all times been the object of much investigation, and though it would not appear to be one of the most difficult, inasmuch as since every one has experience of the passions within himself, there is no necessity to borrow one’s observations from elsewhere in order to discover their nature; yet that which the ancients have taught regarding them is both so slight, and for the most part so far from credible, that I am unable to entertain any hope of approximating to the truth excepting by shunning the paths which they have followed. This is why I shall be here obliged to write just as though I were treating of a matter which no one had ever touched on before me; and, to begin with, I consider that all that which occurs or that happens anew, is by the philosophers, generally speaking, termed a passion, in as far as the subject to which it occurs is concerned, and an action in respect of him who causes it to occur. Thus although the agent and the recipient [patient] are frequently very different, the action and the passion are always one and the same thing, although having different names, because of the two diverse subjects to which it may be related.
ARTICLE II.
That in order to understand the passions of the soul its functions must be distinguished from those of body.
Next I note also that we do not observe the existence of any subject which more immediately acts upon our soul than the body to which it is joined, and that we must consequently consider that what in the soul is a passion is in the body commonly speaking an action; so that there is no better means of arriving at a knowledge of our passions than to examine the difference which exists between soul and body in order to know to which of the two we must attribute each one of the functions which are within us.
ARTICLE III.
What rule we must follow to bring about th is result.
As to this we shall not find much difficulty if we realise that all that we experience as being in us, and that to observation may exist in wholly inanimate bodies, must be attributed to our body alone; and, on the other hand, that all that which is in us and which we cannot in any way conceive as possibly pertaining to a body, must be attributed to our soul.
ARTICLE IV.
That the heat and movement of the members proceed from the body, the thoughts from the soul.
Thus because we have no conception of the body as thinking in any way, we have reason to believe that every kind of thought which exists in us belongs to the soul: and because we do not doubt there being inanimate bodies which can move in as many as or in more diverse modes than can ours, and which have as much heat or move (experience demonstrates this to us in flame, which of itself has much more heat and movement than any of our members), we must believe that all the heat and all the movements which are in us pertain only to body, inasmuch as they do not depend on thought of all
ARTICLE V.
That it is an error to believe that the soul supplies the movement and heat to body.
By this means we shall avoid a very considerable error into which many have fallen; so much so that I am of opinion that this is the primary cause which has prevented our being able hitherto satisfactorily to explain the passions and the other properties of the soul. It arises from the fact that from observing that all dead bodies are devoid of heat and consequently of movement, it has been thought that it was the absence of soul which caused these movements and this heat to cease; and thus, without any reason, it was thought that our natural heat and all the movements of our body depend on the soul: while in fact we ought on the contrary to believe that the soul quits us on death only because this heat ceases, and the organs which serve to move the body disintegrate.
ARTICLE VI.
The difference that exists between a living body and a dead body.
In order, then, that we may avoid this error, let us consider that death never comes to pass by reason of the soul, but only because some one of the principal parts of the body decays; and we may judge that the body of a living man differs from that of a dead man just as does a watch or other automaton (i.e. a machine that moves of itself), when it is wound up and contains in itself the corporeal principle of those movements for which it is designed along with all that is requisite for its action, from the same watch or other machine when it is broken and when the principle of its movement ceases to act.
ARTICLE VII.
A brief explanation of the parts of the body and some of its functions.
In order to render this more intelligible, I shall here explain in a few words the whole method in which the bodily machine is composed. There is no one who does not already know that there are in us a heart, a brain, a stomach, muscles, nerves, arteries, veins, and such things. We also know that the food that we eat descends into the stomach and bowels where its juice, passing into the liver and into all the veins, mingles with, and thereby increases the quantity of the blood which they contain. Those who have acquired even the minimum of medical knowledge further know how the heart is composed, and how all the blood in the veins can easily flow from the vena cava into its right side and from thence pass into the lung by the vessel which we term the arterial vein, and then return from the lung into the left side of the heart, by the vessel called the venous artery, and finally pass from there into the great artery, whose branches spread throughout all the body. Likewise all those whom the authority of the ancients has not entirely blinded, and who have chosen to open their eyes for the purpose of investigating the opinion of Harvey regarding the circulation of the blood, do not doubt that all the veins and arteries of the body are like streams by which the blood ceaselessly flows with great swiftness, taking its course from the right cavity of the heart by the arterial vein whose branches are spread over the whole of the lung, and joined to that of the venous artery by which it passes from the lung into the left side of the heart; from these, again, it goes into the great artery whose branches, spread throughout all the rest of the body, are united to the branches of the vein, which branches once more carry the same blood into the right cavity of the heart. Thus these two cavities are like sluices through each of which all the blood passes in the course of each circuit which it makes in the body. We further know that all the movements of the members depend on the muscles, and that these muscles are so mutually related one to another that when the one is contracted it draws toward itself the part of the body to which it is attached, which causes the opposi
te muscle at the same time to become elongated; then if at another time it happens that this last contracts, it causes the former to become elongated and it draws back to itself the part to which they are attached. We know finally that all these movements of the muscles, as also all the senses, depend on the nerves, which resemble small filaments, or little tubes, which all proceed from the brain, and thus contain like it a certain very subtle air or wind which is called the animal spirits.
ARTICLE VIII.
What is the principle of all these functions!
But it is not usually known in what way these animal spirits and these nerves contribute to the movements and to the senses, nor what is the corporeal principle which causes them to act. That is why, although I have already made some mention of them in my other writings, I shall not here omit to say shortly that so long as we live there is a continual heat in our heart, which is a species of fire which the blood of the veins there maintains, and that this fire is the corporeal principle of all the movements of our members.
ARTICLE IX.
How the movement of the heart is carried on.
Its first effect is to dilate the blood with which the cavities of the heart are filled; that causes this blood, which requires a greater space for its occupation, to pass impetuously from the right cavity into the arterial vein, and from the left into the great artery; then when this dilation ceases, new blood immediately enters from the vena cava into the right cavity of the heart, and from the venous artery into the left; for there are little membranes at the entrances of these four vessels, disposed in such a manner that they do not allow the blood to enter the heart but by the two last, nor to issue from it but by the two others. The new blood which has entered into the heart is then immediately afterwards rarefied, in the same manner as that which preceded it; and it is just this which causes the pulse, or beating of the heart and arteries; so that this beating repeats itself as often as the new blood enters the heart. It is also just this which gives its motion to the blood, and causes it to flow ceaselessly and very quickly in all the arteries and veins, whereby it carries the heat which it acquires in the heart to every part of the body, and supplies them with nourishment.
ARTICLE X.
How the animal spirits are produced in the brain.
But what is here most worthy of remark is that all the most animated and subtle portions of the blood which the heat has rarefied in the heart, enter ceaselessly in large quantities into the cavities of the brain. And the reason which causes them to go there rather than elsewhere, is that all the blood which issues from the heart by the great artery takes its course in a straight line towards that place, and not being able to enter it in its entirety, because there are only very narrow passages there, those of its parts which are the most agitated and the most subtle alone pass through, while the rest spreads abroad in all the other portions of the body. But these very subtle parts of the blood form the animal spirits; and for this end they have no need to experience any other change in the brain, unless it be that they are separated from the other less subtle portions of the blood; for what I here name spirits are nothing but material bodies and their one peculiarity is that they are bodies of extreme minuteness and that they move very quickly like the particles of the flame which issues from a torch. Thus it is that they never remain at rest in any spot, and just as some of them enter into the cavities of the brain, others issue forth by the pores which are in its substance, which pores conduct them into the nerves, and from there into the muscles, by means of which they move the body in all the different ways in which it can be moved.
ARTICLE XI.
How the movements of the muscles take place.
For the sole cause of all the movements of the members is that certain muscles contract, and that those opposite to them elongate, as has already been said; and the sole cause of one muscle contracting rather than that set against it, is that there comes from the brain some additional amount of animal spirits, however little it may be, to it rather than to the other. Not that the spirits which proceed immediately from the brain suffice in themselves to move the muscles, but they determine the other spirits which are already in these two muscles, all to issue very quickly from the one of them and to pass into the other. By this means that from which they issue becomes longer and more flaccid, and that into which they enter, being rapidly distended by them, contracts, and pulls the member to which it is attached. This is easy to understand provided that we know that there are but very few animal spirits which continually proceed from the brain to each muscle, but that there are always a quantity of others enclosed in the same muscle, which move there very quickly, sometimes by only turning about in the place where they are, — that is, when they do not find any passage open from which to issue forth from it — and sometimes by flowing into the opposite muscle; and inasmuch as there are little openings in each of these muscles by which the spirits can flow from one to the other, and which are so arranged that when the spirits that come from the brain to one of them have ever so little more strength than those that proceed to the other, they open all the entrances by which the spirits, of the other muscle can pass into this one, and at the same time close all those by which the spirits of this last can pass into the other. By this means all the spirits formerly contained in these two muscles very quickly collect in one of them and then distend and shorten it, while the other becomes elongated and flaccid.
ARTICLE XII.
How outside objects act upon the organs of the senses.
We have still to understand the reasons why the spirits do not flow always from the brain into the muscles in the same fashion, and why occasionally more flow towards some than towards others. For in addition to the action of the soul which is truly in our case one of these causes, as I shall subsequently explain, there are two others which depend only on the body, and of these we must speak. The first consists in the diversity of movements which are excited in the organs of sense by their objects, and this I have already explained fully enough in the Dioptric: but in order that those who see this work may not be necessitated to read others, I shall here repeat that there are three things to consider in respect of the nerves, i.e. first of all their marrow or interior substance, which extends in the form of little filaments from the brain, from which it originates, to the extremities of the other members to which these filaments are attached; secondly the membranes which surround them, and which, being conterminous with those which envelope the brain, form the little tubes in which these little filaments are enclosed; and finally the animal spirits which, being carried by these same tubes from the brain to the muscles, are the reason of these filaments remaining there perfectly free and extended, so that the least thing that moves the part of the body to which the extremity of any one of them is attached, causes by that same means the part of the brain from which it proceeds to move, just as when one draws one end of a cord the other end is made to move.
ARTICLE XIII.
That this action of outside objects may lead the spirits into the muscles in diverse ways.
And I have explained in the Dioptric how all the objects of sight communicate themselves to us only through the fact that they move locally by the intermission of transparent bodies which are between them and us, the little filaments of the optic nerves which are at the back of our eyes, and then the parts of the brain from which these nerves proceed; I explained, I repeat, how they move them in as many diverse ways as the diversities which they cause us to see in things, and that it is not immediately the movements which occur in the eye, but those that occur in the brain which represent these objects to the soul. To follow this example, it is easy to conceive how sounds, scents, tastes, heat, pain, hunger, thirst and generally speaking all objects of our other external senses as well as of our internal appetites, also excite some movement in our nerves which by their means pass to the brain; and in addition to the fact that these diverse movements of the brain cause diverse perceptions to become evident to our soul, they can a
lso without it cause the spirits to take their course towards certain muscles rather than towards others, and thus to move our limbs, which I shall prove here by one example only. If someone quickly thrusts his hand against our eyes as if to strike us, even though we know him to be our friend, that he only does it in fun, and that he will take great care not to hurt us, we have all the same trouble in preventing ourselves from closing them; and this shows that it is not by the intervention of our soul that they close, seeing that it is against our will, which is its only, or at least its principal activity; but it is because the machine of our body is so formed that the movement of this hand towards our eyes excites another movement in our brain, which conducts the animal spirits into the muscles which cause the eyelids to close.
ARTICLE XIV.
That the diversity which exists between the animal spirits may also cause a diversity in the course they take.
The other cause which serves to conduct the animal spirits differently into the muscles, is the unequal agitation of these spirits and the diversity of their parts. For when some of their parts are more coarse and more agitated than others, they pass further forward in a straight line into the cavities and pores of the brain, and by this means are conducted into other muscles than those they would enter if they had less force.
ARTICLE XV.
The causes of their diversity.
And this inequality may proceed from the diverse matters of which they are composed, as we see in the case of those who have drunk much wine — that the vapours of this wine entering quickly into the blood, rise from the heart to the brain, where they become converted into animal spirits, which, being stronger and more abundant than those ordinarily there, are capable of moving the body in many strange fashions. This inequality of spirits may also proceed from diverse dispositions of the heart, liver, stomach, spleen, and all other parts which contribute to their production; for we must here notice principally certain little nerves inserted in the base of the heart, which serve to enlarge and diminish the entrances of its cavities, whereby the blood dilating there more or less forcibly, produces spirits disposed in diverse ways. We must also notice that although the blood which enters the heart comes there from all other parts of the body, it nevertheless often happens that it is more forcibly driven from some parts than from others, because the nerves and muscles which lead to these particular parts press or agitate it to a greater extent; and that, according to the diversity of the parts from which it conies the most, it dilates variously in the heart and then produces spirits which have different qualities. Thus, for example, that which comes from the lower part of the liver where is the gall, dilates in another fashion in the heart than that which comes from the spleen, and this one again differently from what comes from the veins of the arms or legs, and this finally quite otherwise than the juice of the food when, having newly issued from the stomach and bowels, it at once passes by the liver to the heart.