In Meditations on First Philosophy, Descartes articulated his project toward finding indubitable knowledge by doubting all his beliefs. He did that by introducing an evil spirit devoted to deceiving humans (Descartes, 1984, p. 17). Some hundred years later, Buowsma challenged the role of the evil spirit in Descartes’ project by proposing two possible scenarios for the evil demon to produce illusions. He argued that none of these illusions work, as one is recognisable, so no longer will remain an illusion, and the other is not recognisable at all. If Buowsma is right, the aim of the demon’s tricks to plant the seed of scepticism in the human mind is not achievable (Bouwsm, 1949, p. 141).
Descartes’ intellectual journey toward certainty commenced with systemic doubt. He confessed that his knowledge is dubious because he had accepted many false opinions as true, and he concluded that all his thoughts are founded on shaky assumptions. Then he decided to demolish the whole structure of his knowledge and to reconstruct it on unshakeable principles. Descartes wisely escaped scrutinising his opinions one by one. Instead, he undermined the foundations of his beliefs so that the rest of his thoughts would collapse consequently (Descartes, 2008, pp. 13-14).
The first assumption he tackled was the validity of the knowledge acquired through senses. He argued that in sciences such as physics and medicine that study composite things, senses can be misleading. Although Descartes initially presumed that his understanding of arithmetical axioms and logical principles are indubitable, he considered the possibility that he is being deceived, not only about the testimony of the senses, but also about the truth of arithmetical axioms and logical principles (Descartes, 2008, p. 14).
As a religious person, Descartes rejected the possibility that God is deceiving him. However, he did not turn down the existence of a cunning evil demon devoted to deceiving by illusions and by interference with senses and understandings (Descartes, 2008, p. 16). Descartes argued that even if he grants the logical possibility of the existence of such an evil demon and thereby doubt the certainty of his fundamental beliefs, he cannot doubt that he is a thinking thing. Therefore, he took this certainty as the unshakable cornerstone of knowledge: “I am, I exist” (Descartes, 2008, p. 18).
In Bouwsma’s first scenario, the evil genius plans to deceive Tom by substituting everything with something else - in this phantasy case changing everything with paper. The evil genius thus attempts to manipulate everything and consequently mislead Tom to mistake them for what they are not. However, Tom acknowledged that everything around him has been changed to paper, even himself. This means that Tom is not misled by the evil genius whose aim was to deceive him. Instead, Tom recognises the differences between what he had been experienced before, e.g. flower and its properties, with the flower that has been made of paper (Bouwsm, 1949, pp. 142-143).
In other words, Tom cannot be deceived by the devil demon as long as he recognises the difference between reality and illusion - distinguishes paper flower paper from a flower in the phantasy case. As soon as Tom realises that flowers today just look like flowers but are made of other thing, the illusion is aborted and evil genius’s plan is destroyed. Consequently, Bouwsma argues that tricks of Descartes’ evil spirit can be successfully deceitful only if they remain unrecognised (Bouwsm, 1949, pp. 144-145).
In the second scenario, the evil genius plans to deceive Tom by leading him to mistake nothing for something. In this way, Tom sees, hears, smells and thinks just as anyone else does while there is nothing but illusions. For the evil genius to fulfil this plan, it is not enough to destroy everything but also necessary to manipulate Tom’s memory to mislead him (Bouwsm, 1949, pp. 146-147).
Tom, as planned, does not realise that there is nothing around at all. In other words, he had no external anchor and coherent sense in which he could be said to be deceived. However, Tom’s regular understanding of his surroundings is unpleasant to the evil genius and aroused the evil to convince Tom of a solipsistic world; what he initially has been deceived to believe otherwise. The evil genius attempts to make Tom suspicious by arguing for the unreliability of senses. The evil demon also advises that the whole world is a Thick illusion like the flowers before the mirror. Bouwsma challenges the role of evil spirit and seems to be saying that deception makes sense only in relation to the evil demon’s superhuman power that humans innately lack (Bouwsm, 1949, pp. 148-150).
Bouwsma is right in thinking that Descartes’s evil spirit has two exhaustive types of illusions, and either of them has no deceiving power on the human mind. Although the first type may raise scepticism for humans, it is eventually recognisable. In the second type, everything is destroyed so there is no reality beyond the human mind, and only one's memory is kept untouched. However, even in this type no one can recognise that an illusion has taken place. Therefore, the existence of the evil genius makes no difference in Descartes’ argument for finding certain knowledge (Bouwsm, 1949, p. 151).
In addition, supposing Bouswma succeeds in showing that it is even conceptually impossible for an agent to be deceived by an all-powerful evil demon, even so, he would not have undermined the Cartesian sceptic’s claim that the existence of the external world is not beyond a reasonable doubt. It would still be true that humans’ inference of the existence of the external from the testimony of the senses is not logical and at best is probable. The Cartesian evil demon is meant to illustrate that the falsity of claims about the existence of world beyond humans mind is a possibility. Even if successful, all that Bouwsma’s argument would have shown is that the ‘parable’ of the deceitful demon does not suit the Cartesian’s purposes.
Descartes, René, and Michael Moriarty. Meditations on First Philosophy with Selections from the Objections and Replies. Oxford: Oxford University Press, 2008.
Descartes, René, John Cottingham, Robert Stoothoff, and Dugald Murdoch. The Philosophical Writings of Descartes. Vol. II. Cambridge: Cambridge University Press, 1984.
Bouwsma, O. K. “Descartes' Evil Genius.” The Philosophical Review, no. 2 (1949): 141-51.