Arnauld, Antoine (1612–94)

2. Arnauld and Descartes

Arnauld’s attraction to Descartes’ philosophy began early. His objections to the Meditations are clearly offered in a constructive spirit by an ally who hopes to see the system move towards greater consistency. Descartes, in fact, found Arnauld’s comments to be the most reasonable and serious of all. Arnauld divided his objections into three parts: the first two dealing with ‘philosophical’ issues, the third concentrating on ‘points which may cause difficulty for theologians’. In the first part, ‘The Nature of the Human Mind’, he questions Descartes’ claim that, since it is possible to form a concept of oneself embodying nothing but the certain knowledge that one is a thinking thing, thought alone constitutes one’s essence. The most that can be concluded with certainty from such a premise, Arnauld insists, is ‘that I can obtain some knowledge of myself without knowledge of the body’; not, however, that there is a ‘real distinction in existence between mind and body’. In the second part, ‘Concerning God’, Arnauld raises his famous objection to the circularity of Descartes’ attempts to draw epistemic warrant from demonstrations of God’s existence: ‘I have one further worry, namely, how the author avoids reasoning in a circle when he says that we are sure that what we clearly and distinctly perceive is true only because God exists. But we can be sure that God exists only because we clearly and distinctly perceive this. Hence, before we can be sure that God exists, we ought to be able to be sure that whatever we perceive clearly and evidently is true’ (Arnauld 1641: 32).

In the final part, Arnauld’s most important remark concerns the consequences of Descartes’ metaphysics for the Catholic doctrine of Eucharistic transubstantiation. Descartes has emptied the material world of sensible qualities (colour, taste, smell and so on), leaving behind only extension and its properties, modes which necessarily inhere in a substance. His ontology thus appears to Arnauld to be inconsistent with faith, which has traditionally been aligned with the view that the substance of the bread of the Eucharist is either converted into, or annihilated and replaced by, Christ’s body, and only the accidents of the bread (colour, taste, smell) remain. Such a real existence of accidents, independent of any underlying substance, is ruled out on Cartesian principles. Descartes responded with one of his tentative reinterpretations of transubstantiation. Ironically, it would be on just this issue of the compatibility of Cartesian metaphysics with the Catholic dogma of the Eucharist that Arnauld would become Descartes’ most loyal and vociferous defender over the next fifty years. He generally approved of Cartesianism not just because it seemed closer to the truth than any other system – especially the Aristotelian – but also because its doctrines were the most supportive of Christian piety. Arnauld believed that Descartes ‘has demonstrated the existence of God better than anyone else’, and that his mind–body dualism has laid the surest foundation for the immortality of the soul.