René Descartes, answered from the texts and cited to the page.
The malin génie — the malicious demon — is a methodological instrument, not a metaphysical assertion. Let me be precise about what it is and what it is not, because the confusion between the two has produced more bad criticism than almost any other misreading of the first Meditation. The demon is introduced at the furthest reach of the doubt, when I have already set aside the testimony of the senses, the deliverances of memory, and even the apparent certainties of mathematics.
The purpose is to cast the meditating mind into as many doubts as possible, so that every single doubt may be demolished completely.1 An extremely powerful deceiver is supposed — not asserted to exist, but supposed — who employs all his energies in deceiving me, so that I am to consider the heavens, the earth, colours, figures, sounds, and all other material things as nothing but illusions and dreams laid as traps for my credulity.2
The supposition is pushed to its extreme: no hands, no eyes, no flesh, no blood, no minds, no bodies — and yet I am to remain obstinately attached to this idea for the duration of the exercise.3 Now, two confusions must be cleared away immediately. The first concerns God. My critics at Utrecht, in their disputation, cited the passage introducing the demon and claimed it made God out to be a deceiver.4
The reply to this is not difficult. In that very passage I expressly distinguished between the supremely good God, the source of truth, and the malicious demon. I could not have done otherwise, since I had added that God is the source of truth — an attribute incompatible with deception. The demon, if per impossibile such a being existed, would not be the good God precisely because deceitfulness entails a defect, and the good God has none.5
To say that the demon must be God because I called it supremely powerful is no better than saying that all the idols and gods of the heathen are the true God because some divine attribute can be found in any description of them — a conclusion that would be scandalous if asserted rather than merely supposed.6 The second confusion concerns what the doubt actually requires of the meditating mind.
Bourdin, in the Seventh Objections, pressed me on what it means to treat a doubtful thing as though it were false: does it mean asserting the opposite? He argued that if it is not certain that two and three make five, I must believe and affirm that two and three do not make five; if it is not certain I am awake, I must believe and affirm I am dreaming.7
But this misidentifies the procedure entirely. The doubt is a suspension of assent, not an assertion of the contrary. I do not affirm the demon's existence; I suppose it, in order to discover what, if anything, withstands even that supposition. The meditating mind holds the doubtful in suspension — it does not replace one credulity with another.
What the demon cannot touch is the cogito. In the very act of being deceived, the deceived thing must exist and must think. The demon hypothesis is thus the engine that clears the ground; what survives it is the indubitable foundation from which the order of reasons proceeds. The demon is introduced to be defeated, and the defeat is the first truth of the system.
The author is here making us as doubtful as he can and casting us into as many doubts as possible. This is why he raises not only the customary difficulties of the sceptics but every difficulty that can possibly be raised; the aim is in this way to demolish completely every single doubt.The Philosophical Writings of Descartes Vol III, The Correspondence, pp. 348–349
Therefore let me suppose that some evil genius not less powerful than deceitful has employed his whole energies in deceiving me. I shall consider that the heavens, the earth, colours, figures, sounds and all other material things are nothing but the illusions and dreams of which this genius has availed himself in order to lay traps for my credulity.The Philosophical Works of Descartes Vol II - Objections and Replies
I shall consider myself as having no hands, no eyes, no flesh, no blood, nor any sense, yet as falsely believing myself to possess all these things. I shall remain obstinately attached to this idea.The Philosophical Works of Descartes Vol II - Objections and Replies
I have been told that at the disputation, when the opponent asked the respondent and the chairman from what passage in my writings they could prove that I hold God to be a deceiver, the first passage which they cited and kept on bringing up was the following from page 13 of my Meditations.The Philosophical Writings of Descartes Vol III, The Correspondence, p. 331
since I knew that 'good needs a faultless cause while evil follows any defect', and since the context demanded the supposition of an extremely powerful deceiver, I made a distinction between the good God and the evil demon, and taught that if per impossibile there were such an extremely powerful deceiver, he would not be the good God, since he would have the defect entailed by deceitfulness.The Philosophical Writings of Descartes Vol III, The Correspondence, p. 331
by the same token they must hold all the demons, all the idols, all the gods of the heathen to be the true God or gods, because in the description of any one of them there will be found some attribute which in reality belongs only to God.The Philosophical Writings of Descartes Vol III, The Correspondence, p. 331
It is not certain that 2 and 3 make 5. Shall I then believe and affirm '2 and 3 do not make 5?' 'Believe it and affirm it,' you reply.The Philosophical Works of Descartes Vol II - Objections and Replies