Denis Diderot

Conversation Between DíAlembert and Diderot

Translated by Ian Johnston, Vancouver Island University, Nanaimo, British Columbia, Canada

[The following translation (2014), which has been prepared by Ian Johnston, Emeritus Professor at Vancouver Island University, is a revised version of an earlier translation (originally posted in 2002). Students, teachers, artists, and members of the general public may download and distribute this text. They may also freely edit it to suit their purposes. All commercial use of the translation, however, is prohibited without the permission of the translator. Please contact Ian Johnston for details. This work is the first section of a three-part dramatic conversation. For the Table of Contents of all three parts, please consult the following link: RÍve d'Alembert.

In the following translation the explanatory endnotes have been added by the translator.]

Conversation Between DíAlembert and Diderot

DíALEMBERT: I grant that a Being which exists somewhere yet corresponds to no single point in space, a Being which has no spatial dimensions yet occupies space, which is wholly complete in each part of this space, which is essentially different from material stuff yet is united with it, which is affected by matter and moves it without moving itself, which acts on matter yet is subject to all its changes, a Being about which I havenít the slightest conceptionóa Being with such a contradictory nature is difficult to accept. But there are other obscurities waiting for anyone who rejects such a Being. For in the last analysis, if this sensitivity which you put in its place is a universal and essential quality of matter, then a stone must feel.(1)  

DIDEROT: Well, why not?

DíALEMBERT: Thatís hard to believe.

DIDEROT: Yes, for the man who cuts the stone, carves, and grinds it without hearing it cry out.

DíALEMBERT: I really wish youíd tell me what difference you establish between a man and a statue, between marble and flesh.

DIDEROT: Not much. One can make marble with flesh and flesh with marble.

DíALEMBERT: But one is not the other.

DIDEROT: Just the way what you call living energy is not the same as latent energy.

DíALEMBERT: I donít understand you.

DIDEROT: Let me explain. The transporting of a body from one place to another is not motionóitís only its effect. Motion is equally present both in the transported body and in the one which remains motionless.

DíALEMBERT: That way of seeing it is new.

DIDEROT: Nonetheless, itís true. If you remove the obstacle which prevents the local movement of a stationary body, it will be shifted. If by sudden rarefaction you get rid of the air which surrounds the enormous trunk of this oak tree, then the water it contains will suddenly expand and blow it up into a hundred thousand fragments. Iím saying the same thing is true for your own body.

DíALEMBERT: All right. But whatís the relationship between motion and sensitivity? Could it by chance be the case that you recognize an active sensitivity and a latent sensitivity, just as there is an active and latent force? An active force which manifests itself by displacement, and a latent force which manifests itself by pressure, an active sensitivity which is characterized by certain observable actions in an animal and perhaps in a plant, and a latent sensitivity which we would confirm by its transformation into a condition of active sensitivity.

DIDEROT: Splendid. Youíve got it.

DíALEMBERT: Thus, the statue only has a latent sensitivity, and man, animals, and perhaps even plants are endowed with an active sensitivity.

DIDEROT: Thereís no doubt about this difference between the block of marble and fleshy tissue. But you do understand that thatís not the only difference.

DíALEMBERT: Of course. Whatever resemblance there may be between the exterior form of the man and the statue, there is no connection between their internal organic structures. The chisel of the most expert sculptor canít make even an epidermis. But thereís an extremely simple process for making latent energy transform itself to active energy. Itís an experiment which is repeated a hundred times a day right before our eyes; whereas, I donít see how one can make a body move from a state of latent sensitivity into a state of active sensitivity.

DIDEROT: Thatís because you donít want to see it. The phenomenon is common enough.

DíALEMBERT: Please tell me what this common enough phenomenon is.

DIDEROT: Iíll tell you because you donít mind the shame of being told. It happens every time you eat.

DíALEMBERT: Every time I eat!

DIDEROT: Yes, because when youíre eating, what are you doing? Youíre removing the obstacles which stand in the way of the active sensitivity of what youíre eating. You assimilate the food into yourself. You make flesh out of it. You turn it into animal stuff. You make is capable of sensation. And what you do to food, Iíll do to marble whenever I like.

DíALEMBERT: And how will you do that?

DIDEROT: How? Iíll make it edible.

DíALEMBERT: Make marble edibleóthat doesnít seem easy to me.

DIDEROT: Itís up to me to show you how itís done. I take the statue which you see. I put it into a mortar and with some heavy blows with a pestle . . .

DíALEMBERT: Please go gentlyóitís a masterpiece by Falconet. If it were a piece by Huez or someone else . . .

DIDEROT: That means nothing to Falconet. The statueís paid for, and Falconet doesnít care much what people think of him now and not at all about his future reputation. (2)

DíALEMBERT: All right then, pulverize away.

DIDEROT: When the block of marble has been reduced to a very fine powder, I mix this powder with some humus or topsoil. I knead them together well. I water the mixture and let it rot for a year, two years, a centuryóthe time doesnít matter. When itís all been transformed into almost homogeneous matter, into humus, do you know what I do?

DíALEMBERT: Iím sure you won't be eating the humus.

DIDEROT: No, but there is a way of uniting that humus and myself, of appropriating itóa latus, as the chemist would say.

DíALEMBERT: And this latus is a plant?

DIDEROT: Very good. I sow some peas, beans, cabbages, and other leguminous plants in it. The plants nourish themselves on the earth, and I nourish myself on the plants.

DíALEMBERT: True or false, I like this transformation of marble into humus and of humus into the vegetable realm and of the vegetable realm into the animal realm, into flesh.

DIDEROT: In this way I make flesh or soul, as my daughter saysóactive, sensitive matter. And if I have not resolved the problem which you proposed to me, at least I have come a great deal closer. For you will concede to me that the distance from a piece of marble to a sentient being is a lot further than from a sentient being to a thinking being.

DíALEMBERT: I agree. But for all that a sentient being is still not the same as a thinking being.

DIDEROT: Before taking another pace forward, let me give you the history of one of the greatest mathematicians in Europe. What was he at first, this marvelous being? Nothing at all.

DíALEMBERT: How could he be nothing? Nothing comes from nothing.

DIDEROT: Youíre taking the words too literally. What I mean is that before his mother, the beautiful and scandalous Canoness Tencin, had attained the age of puberty and before the soldier La Touche was an adolescent, the molecules which were to form the first rudiments of my mathematician were scattered in the young and immature mechanical structures of both of them. They were filtered with the lymph and circulated with the blood until finally they settled in the reservoirs destined for their union, the sex glands of his mother and his father. And there this rare germ is formed, and there, according to common opinion, itís led along the fallopian tube into the womb, attaches itself to the womb by a long peduncle, and there grows in stages and develops into the fetal state. Then comes the moment when it leaves its dark prison, and, behold, he is born, exposed on the steps of Saint-Jean-le-Rond, which gave him his name. Taken from the Foundlingís Home, set on the breast of the good wife of a glazier, Madame Rousseau, nursed, grown large in body and mind, he becomes a writer, engineer, and mathematician. How did that all happen? By eating and other purely mechanical operations. Here in four words is the general formula: eat, digest, distil in vasti licito, et fiat homo secundum artem [in the proper container, and let a man be made by the usual art]. And anyone who explained to the Academy the progress of the formation of a man or an animal would only have to refer to material agents whose successive effects would be an inert being, a sentient being, a thinking being, a being solving the problem of the precession of the equinoxes, a sublime being, a marvelous being, a being who grows older, declines, dies, dissolves, and is returned to vegetative earth.(3)

DíALEMBERT: So you donít believe in pre-existing germ cells?


DíALEMBERT: Ah, Iím pleased to hear that.

DIDEROT: Itís against experience and reason. It contradicts the experience of anyone who could have wasted his time looking for these germ cells in the egg and in most animals before a certain age, and it contradicts reason which teaches us that the divisibility of matter has a natural limit, although there is no limit to such divisibility in our understanding, and which rejects the idea of an elephant completely formed in an atom and in this atom another fully shaped elephant, and so on ad infinitum.(4)  

DíALEMBERT: But without these pre-existing germ cells, the original generation of animals cannot be imagined.

DIDEROT: If youíre troubled by the question of whether the egg came before the hen or the hen before the egg, thatís because you assume that animals were originally what they are now. What foolishness! We donít know any more about what they were than we do about what theyíll become. The imperceptible earthworm which moves around in the mud is perhaps in the process of developing into a large animal, and an enormous animal, which astonishes us with its size, is perhaps in the process of developing into an earthworm and is perhaps a unique and momentary production of this planet.

DíALEMBERT: What did you mean by that?

DIDEROT: I was telling you . . . But that will make us digress from our original discussion.

DíALEMBERT: What does that matter? Weíll come back to it or we wonít.

DIDEROT: Will you allow me to leap ahead a few thousand years?

DíALEMBERT: Why not? Time means nothing to nature.

DIDEROT: Youíll consent that I extinguish our sun?

DíALEMBERT: Happilyóall the more so because it wonít be the first one to be extinguished.

DIDEROT: Once the sun goes out, what will happen? The plants will die, the animals will die, and there we have the earthólonely and quiet. Relight this star, and right away you re-establish the necessary cause of an infinite number of new generations, and I wouldnít venture to guarantee that with the succession of ages our plants and animals of today would be reproduced or not reproduced among these new generations.

DíALEMBERT: Why wouldnít the same scattered elements, once they start to reunite, bring back the same results?

DIDEROT: Because everything in nature is interconnected, and the man who assumes a new phenomenon or brings back a moment from the past is creating a new world once again.

DíALEMBERT: Thatís something a profound thinker could not deny. But to return to man, since the universal order wished him to exist. You recall you left me in that transition from a sentient being to a thinking being?

DIDEROT: I remember.

DíALEMBERT: To be frank, youíd do me a great favour to take me beyond that. Iím eager to start thinking.

DIDEROT: But if I didnít manage to succeed what would result, given the sequence of incontestable facts?

DíALEMBERT: Nothing, other than that weíd be stopped in our tracks at that point.

DIDEROT: And to move on further, would we be permitted to invent an agent with contradictory attributes, a word without meaning and unintelligible?


DIDEROT: Could you tell me what the existence of a sentient being is in relation to itself?

DíALEMBERT: Itís the consciousness of having been itself from the first moment of reflection until the present moment.

DIDEROT: And what is this consciousness founded on?

DíALEMBERT: On the memory of its actions.

DIDEROT: And without this memory?

DíALEMBERT: Without this memory thereíd be no "itself." Since it would not sense its existence except at the moment of receiving an impression, it would have no history of its life. Its life would be an interrupted series of sensations in which nothing was connected.

DIDEROT: Very good. Now, what is memory? Where does it arise?

DíALEMBERT: From a certain organic structure which grows, diminishes, and sometimes is lost completely.

DIDEROT: So then, if a being which feels and has this organic structure suitable for memory links together the impressions it receives and forms by this linking together a history of its life and acquires a consciousness of itself, then it denies, it affirms, it concludesóit thinks.

DíALEMBERT: Thatís what it seems to me. I have only one remaining difficulty.

DIDEROT: Youíre wrong. You still have a lot more difficulties.

DíALEMBERT: But one main one. It strikes me that we can think about only one thing at a time and in order to form a simple proposition (Iím not talking about those enormous chains of reasoning which include thousands of ideas in their development), we would say that itís necessary to have at least two things present, the object which seems to sit there under the eye of our understanding, while our understanding is busy with the quality which it will affirm or deny about that object.

DIDEROT: I share that concern. And itís led me sometimes to compare our organic fibres with sensitive vibrating strings. A sensitive vibrating string still oscillates and resonates a long time after one has plucked it. Itís this oscillation, this sort of inevitable resonance, which holds the present object, while our understanding is busy with the quality which is appropriate to it. But vibrating strings have yet another propertyóthey make other strings quiver. And thus an initial idea summons up a second, and these two a third, then all three a fourth, and so it goes, without our being able to set a limit to the ideas which are aroused and linked in a philosopher who meditates or listens to himself in silence and darkness. This instrument makes astonishing leaps, and one recalled idea sometimes is going to set in motion a harmonic at an incomprehensible interval. If the phenomenon is perceptible between resonating strings, inert and separated, how would it not take place between vital points linked together, between continuous and sensitive fibres?

DíALEMBERT: If thatís not true, itís at least very ingenious. But one would be tempted to think that youíre falling imperceptibly into a difficulty which you wished to avoid.

DIDEROT: Whatís that?

DíALEMBERT: You object to the distinction between the two substances, matter and spirit?(5) 

DIDEROT: I donít hide the fact.

DíALEMBERT: Yet if you look closely at this idea, youíre making the understanding of a philosopher an entity distinct from the instrument, a sort of musician who presses his ear against the vibrating strings and makes judgments about their consonance or dissonance.

DIDEROT: Itís possible I have prompted this objection. But perhaps youíd not have made it if youíd considered the difference between the philosophical instrument and the instrumental harpsichord. The philosophical instrument is sentientóhe is at the same time the musician and the instrument. As something sentient he has the momentary consciousness of the sound he is making; as an animal, he has the memory of that. This organic faculty, by linking the sounds he has within him, produces and keeps the melody there. Suppose there is a harpsichord with sensitivity and a memory. Tell me if it wonít know and repeat on its own the melodies you have executed on its keys. We are instruments endowed with sensibility and memory. Our senses are so many keys which are struck by nature surrounding us and which often strike themselves. And there we have, in my judgment, everything which goes on in an organic harpsichord like you and me. Thereís an impression that has its cause either inside or outside the instrument, a sensation which is born from this impression, a sensation which lasts, for it is impossible to imagine that it is made and extinguishes itself in an indivisible instant, another impression which follows this one, and which similarly has its cause either inside or outside the animal, a second sensation and voices which designate them by natural or conventional sounds.

DíALEMBERT: I see. And so if this sentient and animated harpsichord was now endowed with the faculty of feeding and reproducing itself, it would live and, either on its own or with its female partner, give birth to little keyboards, living and resonating.

DIDEROT: No doubt. In your view, is a lark, a nightingale, a musician, or a man anything else? And what other difference do you find between a canary and a canary music box?(6) You see this egg? Thatís what enables us to overturn all the schools of theology and all temples on the earth. What is this egg? An insensible mass before the germ cell is introduced into it, and after the germ cell is introduced, what is it still? An insensible mass. For this germ cell itself is nothing but an inert and basic fluid. How will this mass develop into a different organic structure, into sensibility and life? By heat. What will produce heat in it? Movement. What will be the successive effects of movement? Instead of answering me, sit down, and letís follow these effects with our eyes from moment to moment. First thereís a point which oscillates, a thread which grows and takes on colour, flesh forms, a beak, the tips of wings, eyes, and feet appear, a yellowish material which unwinds and forms intestines. Itís an animal. This animal moves, agitates itself, cries. I hear these cries through the egg shell. It is covered with down. It sees. The weight of its head, which moves back and forth, constantly brings its beak against the inner surface of its prison. And then it breaks the shell. It comes out, it walks, it flies, it responds to a stimulus, it runs off, it comes closer, it complains, suffers, loves, desires, rejoices. It has all your moods and goes through all your actions. Do you claim, with Descartes, that this is a purely imitative machine?(7) But small children will make fun of you, and philosophers will reply that if thatís a machine, then you are another machine. If you admit that between you and the animal there is merely a difference in organic structure, youíll be following good sense and reason, acting in good faith. But people will conclude from all this, in opposition to you, that from an inert material arranged in a certain manner, impregnated with another inert material, and subject to heat and movement, we get sensibility, life, memory, consciousness, passions, and thought. There are only two positions you can take. You can imagine that in the inert mass of the egg there is a hidden element which is waiting for the egg to develop in order to manifest its presence, or you can assume that this imperceptible element has insinuated itself into the egg through the shell at a time determined by the developmental process. But what is this element? Did it occupy space or not? How did it come or escape without moving? Where was it? What was it doing there or somewhere else? Was it created at the necessary moment? Was it already in existence waiting for a home? Was it the same stuff as this home or different? If it was the same, then it was material stuff. If it was different one cannot conceive of its inertia before the development of the egg or of its energy in the developed animal. Listen to yourself, and youíll be ashamed. Youíll feel that, in order not to admit a simple assumption which explains everythingósensitivity as a universal property of matter or a product of organic structureóyouíre rejecting common sense and jumping into an abyss of mysteries, contradictions, and absurdities.

DíALEMBERT: An assumption! Youíre happy to say that. But what if it was a quality essentially incompatible with matter?

DIDEROT: And where do you get the idea that sensibility is essentially incompatible with matter when you donít know the essence of anything, either of matter or of sensitivity? Do you understand better the nature of movement, its existence in a body, and its communication from one body to another?

DíALEMBERT: Without understanding the nature of sensitivity or that of matter, I see that sensitivity is a simple quality, unified, indivisible, and incompatible with a divisible object or substrate.

DIDEROT: Thatís metaphysical and theological mumbo jumbo. What? Donít you see that all qualities, all the sensible forms which make up matter are essentially indivisible? Thereís neither more nor less impenetrability. There is half a round body, but not half roundness. There is more or less motion, but movement is neither more nor lessóitís either there or it isnít. Thereís no such thing as a half or a third or a quarter of a head or an ear or a finger, any more than there is a half, a third, or a quarter of a thought. If in the universe there is not a single molecule which resembles another and in a molecule no point which resembles any other point, admit that the atom itself is endowed with a quality, an indivisible form. Concede that division is incompatible with the essential quality of forms, because it destroys them. Be a physical scientist and admit the production of an effect when you see it produced, even though you canít explain to yourself the connection between the cause and the effect. Be logical and donít substitute for a cause which exists and which explains everything another cause which cannot be conceived and whose connection with the effect is even harder to understand, something which produces an infinite multitude of difficulties and which solves none of them.

DíALEMBERT: Well, what if I give up this cause?

DIDEROT: Then thereís only one substance in the universe, in man and in animals. The canary musical box is made of wood, and man is made of flesh. The canary is made of flesh, and the musician is made of flesh organized differently, but the two of them have the same origin, the same formation, the same functions, and the same end.

DíALEMBERT: And how is the convention of sounds established with your two harpsichords?

DIDEROT: Since an animal is a sensing instrument perfectly similar to another, endowed with the same pattern, equipped with the same strings, plucked in the same manner by joy, sorrow, hunger, thirst, colic, admiration, and terror, it cannot make different sounds at the pole and the equator. Thatís why youíll find in all languages, living or dead, that interjections are almost the same. We have to derive the origin of all conventional sounds from need and proximity. The sensitive instrument or animal has learned from experience that when it emits a certain sound, there then follows some effect outside itself, that other sensing instruments similar to it or other related animals came close, went away, asked for something, offered something, injured, or caressed it, and these effects were linked in its memory and in that of the others to the formation of these sounds. Observe that in human intercourse there are only sounds and actions. And to concede the full strength of my system, notice also that it is subject to the same insurmountable difficulty that Berkeley proposed in arguing against the existence of material bodies.(8) There is a moment of delirium when the sensitive keyboard thought it was the only keyboard in the world and that all harmony in the universe was coming from it all by itself. 

DíALEMBERT: Thereís plenty to talk about there.

DIDEROT: Thatís true.

DíALEMBERT: For example, we donít understand very well in your system how we form syllogisms or how we draw conclusions.

DIDEROT: But we donít draw them at all. They are all derived by nature. The only thing we do is describe conjoined phenomena whose connection is either necessary or contingent, phenomena which we have learned by experience, necessary in mathematics, physics, and other rigorous sciences, and contingent in morality, politics, and other conjectural sciences.

DíALEMBERT: Is it true that the connection between phenomena is less necessary in one case than in another?

DIDEROT: No, but the cause is subject to too many particular vicissitudes which escape us, so that we cannot inevitably count on the effect which will follow. The certainty we have that a violent man will lose his temper when heís insulted is not the same as our certainty that a body which strikes a smaller body will set it in motion.

DíALEMBERT: What about analogies?

DIDEROT: An analogy in the most complex cases is only a three-part rule which takes place in the sensing instrument. If some phenomenon known in nature is followed by some other phenomenon known in nature, what will be the fourth phenomenon which follows from a third, either given by nature or imagined as an imitation of nature? If the lance of an ordinary warrior is ten feet long, what will be the length of Ajaxís lance? If I can throw a stone weighing four pounds, Diomedes should be able to shift a boulder. The strides of the gods and the leaps of their horses will be in the same proportion as the imaginary one between gods and men. Itís a fourth harmonic string, proportional to three others, with which an animal waits for the resonance which it always makes in itself but which does not always occur in nature. That doesnít matter much to the poetóbut itís still the truth. But itís another matter for the philosopher. He must then interrogate nature, which often gives him a phenomenon entirely different from what he had assumed. And then he perceives that the analogy has deceived him.

DíALEMBERT: Farewell, my friend. Good evening. Have a good night.

DIDEROT: Youíre teasing, but youíll dream on your pillow about this conversation, and if it doesnít make consistent sense, then too bad for you, because youíll be forced to adopt some even more ridiculous hypotheses.

DíALEMBERT: Youíre wrong. Iíll go to bed a skeptic, and Iíll get up a skeptic.

DIDEROT: A skeptic! Can one really be a skeptic?

DíALEMBERT: Well, another point? Youíre not going to maintain that Iím not a sceptic, are you? Who knows that better than me?

DIDEROT: Wait a minute.

DíALEMBERT: Hurry up. Iím keen to get to sleep.

DIDEROT: Iíll be brief. Do you think there is a single question ever discussed which a man remains both for and against with an equally strict reasonableness.

DíALEMBERT: No. That would be like the ass of Buridan.(9)

DIDEROT: Then in that case, thereís no scepticism, since, except for mathematical questions, which do not admit the least uncertainty, there is a for and an against in all questions. The balance is never equal, and it is impossible that it does not go down on the side which we believe the most probable.

DíALEMBERT: But in the morning I see probability on my right, and in the afternoon itís on my left.

DIDEROT: That is, youíre dogmatically in favour in the morning and dogmatically against in the afternoon.

DíALEMBERT: And in the evening, when I remember how quick this inconstancy is in my judgments, I believe none of them, neither those of the morning nor of the afternoon.

DIDEROT: That means you donít remember any more the relative persuasiveness of the two opinions between which you oscillated, and this persuasiveness appears too light for you to establish a fixed view, so you take the position of no longer occupying yourself with such problematical subjects, by abandoning the discussion to others and not disputing the question any more.

DíALEMBERT: That could be.

DIDEROT: But if someone took you to one side and questioned you, as a friend, and asked you, in conscience, which of these two positions is the one you find less difficult, in good faith would you have any difficulty in answering? Would you behave like Buridanís ass?

DíALEMBERT: I donít think so.

DIDEROT: Well there you are, my friend. If you think properly about it, youíll find that in everything our true opinion is not one where we have never vacillated but the one to which we most habitually return.

DíALEMBERT: I believe youíre right.

DIDEROT: So do I. Good night, my friend et memento quia pulvis es, et in pulverem revertis [and remember that you are dust and will return to dust]. 

DíALEMBERT: Thatís sad.

DIDEROT: And necessary. Give a man, I donít say immortality, but only twice his lifespan, and youíll see whatíll happen.

DíALEMBERT: What do you want to happen? But why should that matter to me? Let what can happen, happen. I want to sleep. Good night.


(1) Diderotís materialistic view of creation sees sensitivity (or sensation) actually or potentially present in all things, animate and inanimate. [Back to Text]

(2) …tienne Falconet (1716-1791): a leading French sculptor. Jean-Baptiste díHuez (1729-1793): a well-known French sculptor. [Back to Text]

(3) The details of this ďbeingĒ come from díAlembertís life. He was the illegitimate child of Claudine de Tencin (who had entered a convent and later left) and a military officer Louis-Camus Destouches (whom Diderot calls La Touche). Shortly after his birth, his mother abandoned him outside the church mentioned. DíAlembert went into a foundlingsí home and was later adopted. His father continued to provide generous support for his sonís education. DíAlembert took the name Jean Le Rond díAlembert after the church where he was abandoned (Saint-Jean-le-Rond) and went on to become an outstanding and celebrated mathematician and a leading figure in the Enlightenment. The collection of special cells from all over body in the sexual organs and the ďblendingĒ of those cells from the father and mother in the offspring was one of a number of theories of inheritance at the time. The precession of the equinoxes is a slow change in the orientation of the rotational axis of the earth (like the wobble on a top). DíAlembert refined the equations used to explain the phenomenon. [Back to Text]

(4) The ďpreformationĒ hypothesis held that the reproductive material consists of an infinite series of tiny adult forms one inside another (like a collection of Russian wooden dolls). [Back to Text]

 (5) Diderotís text says ďdistinction between two substances,Ē a reference to the belief that mind and matter are fundamentally different (as Descartes maintained). Diderot is committed to a thoroughgoing materialism. I have added ďmatter and spiritĒ to make this point clear. [Back to Text]

(6)Diderotís word for ďcanary music boxĒ is serinette, a small barrel organ used to teach canaries to sing certain tunes. Renť Descartes (1596-1650), the celebrated and influential French philosopher, maintained that mind and soul were distinct from body and that animals were without souls or mind and were merely mechanical. [Back to Text]

(7) Descartesí writings established the famous mind-body problem: if mind is essentially different from matter then where does it come from if all the rest of the world is material stuff and how can mind and matter interact if they are fundamentally different (for it is clear that they do interact). Diderot is addressing this problem by denying that mind and matter are different. [Back to Text]

(8) George Berkeley (1685-1753), an Irish bishop, proposed that since minds could not have direct contact with things but only with ideas of things, nothing in the world exists outside our own minds. In order to exist, things must be perceived. [Back to Text]

(9) Jean Burdian (c. 1300-c. 1358): a French priest whose name is associated with a paradox: if a rational ass is placed exactly half way between two identical piles of hay, it will starve to death because it has no reason to prefer one pile over the other. In some versions the ass is both hungry and thirsty and the choice is between a bale of hay and a bucket of water. [Back to Text]


Link to DíAlembertís Dream and Sequel to the Preceding Conversation.