SPINOZA: Matter and Mind

Reference: The Story of Philosophy

This paper presents Chapter IV Section 4.2 from the book THE STORY OF PHILOSOPHY by WILL DURANT. The contents are from the 1933 reprint of this book by TIME INCORPORATED by arrangement with Simon and Schuster, Inc.

The paragraphs of the original material (in black) are accompanied by brief comments (in color) based on the present understanding.  Feedback on these comments is appreciated.

The heading below is linked to the original materials.


IV.2 Matter and Mind

But what is mind, and what is matter? Is the mind material, as some unimaginative people suppose; or is the body merely an idea, as some imaginative people suppose? Is the mental process the cause, or the effect, of the cerebral process?—or are they, as Malebranche taught, unrelated and independent, and only providentially parallel? 

Is the mind material, or is the body merely an idea?

Neither is mind material, answers Spinoza, nor is matter mental; neither is the brain-process the cause, nor is it the effect of thought; nor are the two processes independent and parallel. For there are not two processes, and there are not two entities; there is but one process, seen now inwardly as thought, and now outwardly as motion; there is but one entity, seen now inwardly as mind, now outwardly as matter, but in reality an inextricable mixture and unity of both. Mind and body do not act upon each other, because they are not other, they are one. “The body cannot determine the mind to think; nor the mind determine the body to remain in motion or at rest, or in any other state,” for the simple reason that “the decision of the mind, and the desire and determination of the body … ,are one and. the same thing.” And all the world is unifiedly double in this way; wherever there is an external “material” process, it is but one side or aspect of the real process, which to a fuller view would be seen to include as well an internal process correlative, in however different a degree, with the mental process which we see within ourselves. The inward and “mental” process corresponds at every stage with the external and “material” process; “the order and connection of ideas is the same as the order and connection of things.” “Thinking substance and extended substance are one and the same thing, comprehended now through this, now through that, attribute” or aspect. “Certain of the Jews seem to have perceived this, though confusedly; for they said that God and his intellect, and the things conceived by his intellect, were one and the same thing.”

Mind (thought) and matter (motion) are but one process. Mind and body do not act upon each other because they are not other, they are one.

If “mind” be taken in a large sense to correspond with the nervous system in all its ramifications, then every change in the “body” will be accompanied by—or, better, form a whole with—a correlative change in the “mind.” “Just as thoughts and mental processes are connected and arranged in the mind, so in the body its modifications, and the modifications of things” affecting the body through sensations, “are arranged according to their order”; and “nothing can happen to the body which is not perceived by the mind,” and consciously or unconsciously felt. Just as the emotion as felt is part of a whole, of which changes in the circulatory and respiratory and digestive systems are the basis; so an idea is a part, along with “bodily” changes, of one complex organic process; even the infinitesimal subtleties of mathematical reflection have their correlate in the body. (Have not the “behaviorists” proposed to detect a man’s thoughts by recording those involuntary vibrations of the vocal cords that seem to accompany all thinking?) 

Every change in the “body” is accompanied by a correlative change in the “mind” and vice versa.

After so trying to melt away the distinction between body and mind, Spinoza goes on to reduce to a question of degree the difference between intellect and will. There are no “faculties” in the mind, no separate entities called intellect or will, much less imagination or memory; the mind is not an agency that deals with ideas, but it is the ideas themselves in their process and concatenation. Intellect is merely an abstract and short-hand term for a series of ideas; and will an abstract term for a series of actions or volitions: “the intellect and the will are related to this or that idea or volition as rockiness to this or that rock.” Finally, “will and intellect are one and the same thing; for a volition is merely an idea which, by richness of associations (or perhaps through the absence of competitive ideas), has remained long enough in consciousness to pass over into action. Every idea becomes an action unless stopped in the transition by a different idea; the idea is itself the first stage of a unified organic process of which external action is the completion. 

The difference between intellect and will is a question of degree. Intellect is merely an abstract and short-hand term for a series of ideas; and will an abstract term for a series of actions or volitions.

What is often called will, as the impulsive force which determines the duration of an idea in consciousness, should be called desire,—which “is the very essence of man.” Desire is an appetite or instinct of which we are conscious; but instincts need not always operate through conscious desire.* Behind the instincts is the vague and varied effort for self-preservation (conatus sese preservandi); Spinoza sees this in all human and even infra-human activity, just as Schopenhauer and Nietzsche were to see the will to live or the will to power everywhere. Philosophers seldom disagree. 

*Spinoza is alive to the power of the “unconscious,” as seen in somnambulism; and notes the phenomena of double personality. 

The very essence of man is desire—an appetite or instinct—underlying which is the vague effort for self-preservation. It expresses itself as an impulsive force, often called will.

“Everything, in so far as it is in itself, endeavors to persist in its own being; and the endeavor wherewith a thing seeks to persist in its own being is nothing else than the actual essence of that thing”; the power whereby a thing persists is the core and essence of its being. Every instinct is a device developed by nature to preserve the individual (or, as our solitary bachelor fails to add, the species or the group.) Pleasure and pain are the satisfaction or the hindrance of an instinct; they are not the causes of our desires, but their results; we do not desire things because they give us pleasure; but they give us pleasure because we desire them; and we desire them because we must.

Every instinct is a device developed by nature to preserve the individual, the group or the species. Pleasure and pain are the satisfaction or the hindrance of an instinct.

There is, consequently, no free will; the necessities of survival determine instinct, instinct determines desire, and desire determines thought and action. “The decisions of the mind are nothing save desires, which vary according to various dispositions.” “There is in the mind no absolute or free will; but the mind is determined in willing this or that by a cause which is determined in its turn by another cause, and this by another, and so on to infinity.” “Men think themselves free because they are conscious of their volitions and desires; but are ignorant of the causes by which they are led to wish and desire.” Spinoza compares the feeling of free will to a stone’s thinking, as it travels through space, that it determines its own trajectory and selects the place and time of its fall. 

The necessities of survival determine instinct, instinct determines desire, and desire determines thought and action. There is, consequently, no free will.

Since human actions obey laws as fixed as those of geometry, psychology should be studied in geometrical form, and with mathematical objectivity. “I will write about human beings as though I were concerned with lines and planes and solids.” “I have labored carefully not to mock, lament, or execrate, but to understand, human actions; and to this end I have looked upon passions … not as vices of human nature, but as properties just as pertinent to it as are heat, cold, storm, thunder and the like to the nature of the atmosphere.” It is this impartiality of approach that gives to Spinoza’s study of human nature such superiority that Froude called it “the most complete by far which has ever been made by any moral philosopher.” Taine knew no better way of praising Beyle’s analysis than to compare it with Spinoza’s; while Johannes Müller, coming to the subject of the instincts and emotions, wrote: “With regard to the relations of the passions to one another apart from their physiological conditions, it is impossible to give any better account than that which Spinoza has laid down with unsurpassed mastery,”—and the famous physiologist, with the modesty which usually accompanies real greatness, went on to quote in extenso the third book of the Ethics. It is through that analysis of human conduct that Spinoza approaches at last the problems which give the title to his masterpiece. 

Spinoza’s approach to the understanding of human nature is completely objective and his description is unsurpassed.


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  • vinaire  On November 10, 2021 at 5:39 AM

    The concept of mental matrix is totally consistent with Spinoza’s philosophy.


  • vinaire  On November 10, 2021 at 5:40 AM

    Hubbard’s philosophy is all about free will of thetan. It contradicts Spinoza’s philosophy.


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