Philosophical Dictionary, by Voltaire


§ I.

I have seen a somnambulist, but he contented himself with rising, dressing himself, making a bow, and dancing a minuet, all which he did very properly; and having again undressed himself, returned to bed and continued to sleep.

This comes not near the somnambulist of the “Encyclopædia.” The last was a young seminarist, who set himself to compose a sermon in his sleep. He wrote it correctly, read it from one end to the other, or at least appeared to read it, made corrections, erased some lines, substituted others, and inserted an omitted word. He even composed music, noted it with precision, and after preparing his paper with his ruler, placed the words under the notes without the least mistake.

It is said, that an archbishop of Bordeaux has witnessed all these operations, and many others equally astonishing. It is to be wished that this prelate had affixed his attestation to the account, signed by his grand vicars, or at least by his secretary.

But supposing that this somnambulist has done all which is imputed to him, I would persist in putting the same queries to him as to a simple dreamer. I would say to him: You have dreamed more forcibly than another; but it is upon the same principle; one has had a fever only, the other a degree of madness; but both the one and the other have received ideas and sensations to which they have not attended. You have both done what you did not intend to do.

Of two dreamers, the one has not a single idea, the other a crowd; the one is as insensible as marble, while the other experiences desires and enjoyments. A lover composes a song on his mistress in a dream, and in his delirium imagines himself to be reading a tender letter from her, which he repeats aloud:

Scribit amatori meretrix; dat adultera munus

In noctis spatio miserorum vulnera durant.

— Petronius, chap. civ.

Does anything pass within you during this powerful dream more than what passes every day when you are awake?

You, Mr. Seminarist, born with the gift of imitation, you have listened to some hundred sermons, and your brain is prepared to make them: moved by the talent of imitation, you have written them waking; and you are led by the same talent and impulse when you are asleep. But how have you been able to become a preacher in a dream? You went to sleep, without any desire to preach. Remember well the first time that you were led to compose the sketch of a sermon while awake. You thought not of it a quarter of an hour before; but seated in your chamber, occupied in a reverie, without any determinate ideas, your memory recalls, without your will interfering, the remembrance of a certain holiday; this holiday reminds you that sermons are delivered on that day; you remember a text; this text suggests an exordium; pens, ink, and paper, are lying near you; and you begin to write things you had not the least previous intention of writing. Such is precisely what came to pass in your noctambulism.

You believe yourself, both in the one and the other occupation, to have done only what you intended to do; and you have been directed without consciousness by all which preceded the writing of the sermon.

In the same manner when, on coming from vespers, you are shut up in your cell to meditate, you have no design to occupy yourself with the image of your fair neighbor; but it somehow or another intrudes; your imagination is inflamed; and I need not refer to the consequences. You may have experienced the same adventure in your sleep.

What share has your will had in all these modifications of sensation? The same that it has had in the coursing of your blood through your arteries and veins, in the action of your lymphatic vessels, or in the pulsation of your heart, or of your brain.

I have read the article on “Dreams” in the “Encyclopædia,” and have understood nothing; and when I search after the cause of my ideas and actions, either in sleeping or waking, I am equally confounded.

I know well, that a reasoner who would prove to me when I wake, and when I am neither mad nor intoxicated, that I am then an active agent, would but slightly embarrass me; but I should be still more embarrassed if I undertook to prove to him that when he slept he was passive and a pure automaton.

Explain to me an animal who is a mere machine one-half of his life, and who changes his nature twice every twenty-four hours.

§ II.
Letter on Dreams to the Editor of the Literary Gazette, August, 1764.


All the objects of science are within your jurisdiction; allow chimeras to be so also. “Nil sub sole novum” —“nothing new under the sun. Thus it is not of anything which passes in noonday that I am going to treat, but of that which takes place during the night. Be not alarmed; it is only with dreams that I concern myself.

I confess, gentlemen, that I am constantly of the opinion of the physician of M. Pourceaugnac; he inquires of his patient the nature of his dreams, and M. Pourceaugnac, who is not a philosopher, replies that they are of the nature of dreams. It is most certain however, with no offence to your Limousin, that uneasy and horrible dreams denote pain either of body or mind; a body overcharged with aliment, or a mind occupied with melancholy ideas when awake.

The laborer who has waked without chagrin, and fed without excess, sleeps sound and tranquil, and dreams disturb him not; so long as he is in this state, he seldom remembers having a dream — a truth which I have fully ascertained on my estate in Herefordshire. Every dream of a forcible nature is produced by some excess, either in the passions of the soul, or the nourishment of the body; it seems as if nature intended to punish us for them, by suggesting ideas, and making us think in spite of ourselves. It may be inferred from this, that those who think the least are the most happy; but it is not that conclusion which I seek to establish.

We must acknowledge, with Petronius, “Quid-quid luce fuit, tenebris agit.” I have known advocates who have pleaded in dreams; mathematicians who have sought to solve problems; and poets who have composed verses. I have made some myself, which are very passable. It is therefore incontestable, that consecutive ideas occur in sleep, as well as when we are awake, which ideas as certainly come in spite of us. We think while sleeping, as we move in our beds, without our will having anything to do either in the motive or the thought. Your Father Malebranche is right in asserting that we are not able to give ourselves ideas. For why are we to be masters of them, when waking, more than during sleep? If your Malebranche had stopped there, he would have been a great philosopher; he deceived himself only by going too far: of him we may say:

Processit longe flammantia mœnia mundi.

— Lucretius, i, 74.

His vigorous and active mind was hurled

Beyond the flaming limits of this world.

— Creech.

For my part, I am persuaded that the reflection that our thoughts proceed not from ourselves, may induce the visit of some very good thoughts. I will not, however, undertake to develop mine, for fear of tiring some readers, and astonishing others.

I simply beg to say two or three words in relation to dreams. Have you not found, like me, that they are the origin of the opinion so generally diffused throughout antiquity, touching spectres and manes? A man profoundly afflicted at the death of his wife or his son, sees them in his sleep; he speaks to them; they reply to him; and to him they have certainly appeared. Other men have had similar dreams; it is therefore impossible to deny that the dead may return; but it is certain, at the same time, that these deceased, whether inhumed, reduced to ashes, or buried in the abyss of the sea, have not been able to reserve their bodies; it is, therefore, the soul which we have seen. This soul must necessarily be extended, light, and impalpable, because in speaking to it we have not been able to embrace it: “Effugit imago par levibus ventis.” It is moulded and designed from the body that it inhabits, since it perfectly resembles it. The name of shade or manes is given it; from all which a confused idea remains in the head, which differs itself so much more because no one can understand it.

Dreams also appear to me to have been the sensible origin of primitive prophecy or prediction. What more natural or common that to dream that a person dear to us is in danger of dying, or that we see him expiring? What more natural, again, than that such a person may really die soon after this ominous dream of his friend? Dreams which have come to pass are always predictions which no one can doubt, no account being taken of the dreams which are never fulfilled; a single dream accomplished has more effect than a hundred which fail. Antiquity abounds with these examples. How constructed are we for the reception of error! Day and night unite to deceive us!

You see, gentlemen, that by attending to these ideas, we may gather some fruit from the book of my compatriot, the dreamer; but I finish, lest you should take me myself for a mere visionary.

Yours, John Dreamer.

§ III.
Of Dreams.

According to Petronius, dreams are not of divine origin, but self-formed:

Somnia quæ mentes ludunt volitantibus umbris,

Non delumbra deum nec ab æthere numina mittunt,

Sed sibi quisque facit.

But how, all the senses being defunct in sleep, does there remain an internal one which retains consciousness? How is it, that while the eyes see not, the ears hear not, we notwithstanding understand in our dreams? The hound renews the chase in a dream: he barks, follows his prey, and is in at the death. The poet composes verses in his sleep; the mathematician examines his diagram; and the metaphysician reasons well or ill; of all which there are striking examples.

Are they only the organs of the machine which act? Is it the pure soul, submitted to the empire of the senses, enjoying its faculties at liberty?

If the organs alone produce dreams by night, why not alone produce ideas by day? If the soul, pure and tranquil, acting for itself during the repose of the senses, is the sole cause of our ideas while we are sleeping, why are all these ideas usually irregular, unreasonable, and incoherent? What! at a time when the soul is least disturbed, it is so much disquieted in its imagination? Is it frantic when at liberty? If it was produced with metaphysical ideas, as so many sages assert who dream with their eyes open, its correct and luminous ideas of being, of infinity, and of all the primary principles, ought to be revealed in the soul with the greatest energy when the body sleeps. We should never be good philosophers except when dreaming.

Whatever system we embrace, whatever our vain endeavors to prove that the memory impels the brain, and that the brain acts upon the soul, we must allow that our ideas come, in sleep, independently of our will. It is therefore certain that we can think seven or eight hours running without the least intention of doing so, and even without being certain that we think. Pause upon that, and endeavor to divine what there is in this which is animal.

Dreams have always formed a great object of superstition, and nothing is more natural. A man deeply affected by the sickness of his mistress dreams that he sees her dying; she dies the next day; and of course the gods have predicted her death.

The general of an army dreams that he shall gain a battle; he subsequently gains one; the gods had decreed that he should be a conqueror. Dreams which are accomplished are alone attended to. Dreams form a great part of ancient history, as also of oracles.

The “Vulgate” thus translates the end of Leviticus, xix, 26: “You shall not observe dreams.” But the word “dream” exists not in the Hebrew; and it would be exceedingly strange, if attention to dreams was reproved in the same book in which it is said that Joseph became the benefactor of Egypt and his family, in consequence of his interpretation of three dreams.

The interpretation of dreams was a thing so common, that the supposed art had no limits, and the interpreter was sometimes called upon to say what another person had dreamed. Nebuchadnezzar, having forgotten his dream, orders his Magi to say what it was he had dreamed, and threatened them with death if they failed; but the Jew Daniel, who was in the school of the Magi, saved their lives by divining at once what the king had dreamed, and interpreting it. This history, and many others, may serve to prove that the laws of the Jews did not forbid oneiromancy, that is to say, the science of dreams.

§ IV.

In one of my dreams, I supped with M. Touron, who appeared to compose verses and music, which he sang to us. I addressed these four lines to him in my dream:

Mon cher Touron, que tu m’enchantes

Par la douceur de tes accens!

Que tes vers sont doux et coulans!

Tu les fais comme tu les chantes,

Thy gentle accents, Touron dear,

Sound most delightful to my ear!

With how much ease the verses roll,

Which flow, while singing, from thy soul!

In another dream, I recited the first canto of the “Henriade” quite different from what it is. Yesterday, I dreamed that verses were recited at supper, and that some one pretended they were too witty. I replied that verses were entertainments given to the soul, and that ornaments are necessary in entertainments.

I have therefore said things in my sleep which I should have some difficulty to say when awake; I have had thoughts and reflections, in spite of myself, and without the least voluntary operation on my own part, and nevertheless combined my ideas with sagacity, and even with genius. What am I, therefore, if not a machine?

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