QuestionsIs the mind the brain?The egg: matter can think
Is the mind the brain?The mind comes from matter

The egg: matter can think

Denis Diderot 1713 · 1784Gather all human knowledge in the Encyclopédie.
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What it claims

Sensitivity and thought come from organised matter: there is only one substance, in the universe as in man.

Why

In an egg, inert matter becomes a being that feels and thinks; explaining this by a hidden non-material element explains nothing.

In short

"The egg: matter can think" is an argument by Denis Diderot (D'Alembert's Dream, 1769) on the question "Is the mind the brain?" (answer: the mind comes from matter). Its claim: Sensitivity and thought come from organised matter: there is only one substance, in the universe as in man. According to AskPhilosophy's logic check (Z3 solver), the conclusion does follow from its 4 premises. AskPhilosophy presents 4 objections, 3 of them with a documented reply, and the original text behind each premise, checked word for word.

D'Alembert's Dream, 1769
Valid

Look at an egg. At first, a mass that feels nothing. With a little warmth, out comes a chick that sees, cries, suffers, desires. For Diderot, there is no need to imagine a soul that entered the egg: organised matter is enough to produce sensitivity, then thought. He says so under his own name, but in a dialogue he never published.

P1In the egg, inert matter, with only warmth and motion, becomes a being that feels, remembers, desires and thinks.
P2To avoid this, one would have to suppose a non-material element hidden in the egg, of which we cannot say where it was, how it came, or whether it takes up space.
P3When we see an effect produced, we must accept it even without understanding the link; and not replace it with an inconceivable cause that creates more difficulties than it solves.
P4There are only two options: a hidden non-material element, or a sensitivity belonging to matter itself, once organised.
Therefore sensitivity and thought come from organised matter: there is only one substance, in the universe as in man.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
The argument is valid and each premise is essential. It has no hidden premise, but its strength rests on P3: a rule of method, which says to prefer the cause we see at work, even if we do not understand how it works. Dualists attack this rule (Leibniz) or P4 (Descartes: the mind cannot belong to a divisible thing).
Analogy. Raw dough becomes a cake in the oven. No one thinks a "spirit of the cake" entered the oven: heat reorganised the matter. Diderot says the same of the egg that becomes a chick, and of the child who becomes a scholar.

Objections

4

Each objection is a conversation: click to see who replies and where the debate stands.

D
D'Alembert (in the dialogue) attacks premise 4

If sensitivity is a general property of matter, then the stone must feel. That is hard to believe.

Diderot replies
Diderot In the dialogue
The stone has only an "inert" sensitivity, like a force that does not yet move. It becomes active when matter is assimilated and organised: by eating, you turn food into sensitive flesh; one could do the same with marble ground into soil.
Descartes 1641 · attacks premise 4

The body is always divisible, the mind is not: there is no half of a thought. An indivisible thing cannot be a property of a divisible thing; so the mind is not matter.

Diderot replies
Diderot In the Dream, against d'Alembert, who uses this argument
All qualities of matter are indivisible. There is half of a round body, but not half of roundness. So the indivisibility of thought does not prove that it belongs to something other than matter.
Leibniz (the mill) 1714 · attacks premise 3

Enlarge a thinking machine until you can walk into it like a mill: you will see only parts pushing one another, never a perception. If matter produced thought, we should be able to understand how. Accepting an effect with no conceivable link is not explaining it.

Diderot replies
Diderot In the Dream (answer to d'Alembert; Leibniz is not named)
How do you know that sensitivity is incompatible with matter? You know the essence neither of matter nor of sensitivity. We do not understand any better how motion passes from one body to another, and yet we accept it.
The "hard problem" of consciousness (Chalmers) 1995 · attacks premise 1

The egg shows that thought appears with organised matter, not that matter explains it. We can describe everything a brain does without explaining why there is something it feels like. Correlation is not production.

no reply
summary: their text is not yet in our corpus
No reply possible: objection raised in 1995, after the author's death (1784).