The Philosophy of Spinoza

by Benedictus de Spinoza

Here therefore particularly is it to be observed how easily we are deceived when we confuse universals with individuals, and the entities of reason and abstractions with realities.

With regard to the fourth objection, I say that I entirely grant that if a man were placed in such a state of equilibrium he would perish of hunger and thirst, supposing he perceived nothing but hunger and thirst, and the food and drink which were equidistant from him. If you ask me whether such a man would not be thought an ass rather than a man, I reply that I do not know; nor do I know what ought to be thought of a man who hangs himself, or of children, fools, and madmen.

The Independence of Mind and Body

All modes of thought have God for a cause in so far as He is a thinking thing, and not in so far as He is manifested by any other attribute. That which determines the mind to thought, therefore, is a mode of thought and not of extension, that is to say, it is not the body. Again, the motion and rest of the body must be derived from some other body, which has also been determined to motion or rest by another, and, absolutely, whatever arises in the body must arise from God, in so far as He is considered as affected by some mode of extension, and not in so far as He is considered as affected by any mode of thought, that is to say, whatever arises in the body cannot arise from the mind, which is a mode of thought. Therefore, the body cannot determine the mind to thought, neither can the mind determine the body to motion nor rest, nor to anything else, if there be anything else.

This proposition will be better understood from what has been said, that is to say, that the mind and the body are one and the same thing, conceived at one time under the attribute of thought, and at another under that of extension. For this reason, the order or concatenation of things is one, whether nature be conceived under this or under that attribute, and consequently the order of the actions and passions of our body is coincident in Nature with the order of the actions and passions of the mind.

Although these things are so, and no ground for doubting remains, I scarcely believe, nevertheless, that, without a proof derived from experience, men will be induced calmly to weigh what has been said, so firmly are they persuaded that, solely at the bidding of the mind, the body moves or rests, and does a number of things which depend upon the will of the mind alone, and upon the power of thought. For what the body can do no one has hitherto determined, that is to say, experience has taught no one hitherto what the body, without being determined by the mind, can do and what it cannot do from the laws of Nature alone, in so far as Nature is considered merely as corporeal. For no one as yet has understood the structure of the body so accurately as to be able to explain all its functions, not to mention the fact that many things are observed in brutes which far surpass human sagacity, and that sleep-walkers in their sleep do very many things which they dare not do when awake; all this showing that the body itself can do many things from the laws of its own nature alone at which the mind belonging to that body is amazed.

Again, nobody knows by what means or by what method the mind moves the body, nor how many degrees of motion it can communicate to the body, nor with what speed it can move the body. So that it follows that when men say that this or that action of the body springs from the mind which has commanded over the body, they do not know what they say, and they do nothing but confess with pretentious words that they know nothing about the cause of the action, and see nothing in it to wonder at.

But they will say, that whether they know or do not know by what means the mind moves the body, it is nevertheless in their experience that if the mind were not fit for thinking the body would be inert. They say, again, it is in their experience that the mind alone has power both to speak and be silent, and to do many other things which they therefore think to be dependent on a decree of the mind.

But with regard to the first assertion, I ask them if experience does not also teach that if the body be sluggish the mind at the same time is not fit for thinking? When the body is asleep, the mind slumbers with it, and has not the power to think, as it has when the body is awake. Again, I believe that all have discovered that the mind is not always equally fitted for thinking about the same subject, but in proportion to the fitness of the body for this or that image to be excited in it will the mind be better fitted to contemplate this or that object. But my opponents will say, that from the laws of Nature alone, in so far as it is considered to be corporeal merely, it cannot be that the causes of architecture, painting, and things of this sort, which are the results of human art alone, could be deduced, and that the human body, unless it were determined and guided by the mind, would not be able to build a temple. I have already shown, however, that they do not know what the body can do, nor what can be deduced from the consideration of its nature alone, and that they find that many things are done merely by the laws of Nature which they would never have believed to be possible without the direction of the mind, as, for example, those things which sleep-walkers do in their sleep, and at which they themselves are astonished when they wake. I adduce also here the structure itself of the human body, which so greatly surpasses in workmanship all those things which are constructed by human art, not to mention what I have already proved, that an infinitude of things follows from Nature under whatever attribute it may be considered.

With regard to the second point, I should say that human affairs would be much more happily conducted if it were equally in the power of men to be silent and to speak. But experience shows over and over again that there is nothing which men have less power over than the tongue, and that there is nothing which they are less able to do than to govern their appetites, so that many persons believe that we do those things only with freedom which we seek indifferently; as the desire for such things can easily be lessened by the recollection of another thing which we frequently call to mind; it being impossible, on the other hand, to do those things with freedom which we seek with such ardor that the recollection of another thing is unable to mitigate it.