In his works, he sought to synthesise the thought of St. Augustine and Descartes, in order to demonstrate the active role of God in every aspect of the world.

Most importantly, in the third book, which discussed pure understanding, he defended a claim that the ideas through which we perceive objects exist in God.

Here, he made it explicit that the generality of the laws whereby God regulated His behaviour extended not only to His activity in the natural world but also applied to His gift of grace to human beings.

Arnauld's supporters managed to persuade the Roman Catholic Church to place Nature and Grace on its Index of Prohibited Books in 1690, and it was followed there by the Search nineteen years later.

Other critics with whom Malebranche entered into significant discussion include another fellow Cartesian, Pierre Sylvain Regis, as well as Dortous de Mairan.

Like René Descartes, Malebranche held that humans attain knowledge through ideas – immaterial representations present to the mind.

His great innovation was to explain how these same divine ideas could also serve as the immediate objects of human minds in sensual perception.

Malebranche's solution was to suggest that, whereas the mind's intellectual conception of these ideas is pure and direct, its sensual perception of them will be modified by "sensations".

He is noted particularly for his view that we see all things in God and for his adoption of psycho-physical parallelism and 'occasionalism' to deal with the problem of interaction between mind and body.

(This may be a misrepresentation of Malebranche's view; see the first chapter of The Search for Truth, where he specifies that while we cannot but desire the good in general, we are free to apply that love to particulars, and can do so in a disordered fashion that leads to sin.

Malebranche's doctrine, which could be found in contemporary commentaries on Aristotle, and which first appeared in certain Arab philosophers, is therefore called "occasionalism".

Newton had already developed his position some thirty years earlier, but Malebranche probably would not have been aware of it until it was finally published in the Opticks of 1704, or, more likely, in its Latin translation of 1706.

When Malebranche revised his 1699 paper for inclusion as the Sixteenth Elucidation of the 1712 edition of The Search After Truth, he inserted a number of references to "Newton's excellent work".

Malebranche introduced l'Hôpital to Johann Bernoulli, with the ultimate result being the publication of the first textbook in infinitesimal calculus.

According to Malebranche, "an infinite series of plants and animals were contained within the seed or the egg, but only naturalists with sufficient skill and experience could detect their presence" (Magner 158–9).

He was, however, held in widespread high regard within his own lifetime and for some time afterwards, and the influence of certain of his ideas can be discerned in the works of several important figures.

[5] In note H to his "Zeno of Elea" article, Bayle discussed Malebranche's views on material substance with particular approval.

Descartes had also maintained that matter was not directly perceivable, but he had argued that the veracity of God could support a proof of its certain existence.

Berkeley, influenced both by Bayle and directly by Malebranche himself, simply took the final step to a full denial of the existence of material substance.

(Arthur Collier, who was also influenced directly by Malebranche, and by Norris, made the same move at around the same time as Berkeley did, but, it would appear, entirely independently of him.)

David Hume supported and drew upon Malebranche's negative arguments to show that no genuine causal connections could be conceived between distinct mundane entities.

Likewise, Locke felt that Malebranche's metaphysical speculations lacked a proper foundation, and, though ingenious, were ultimately unintelligible.

"[9] Much as Locke predicted, Malebranche's reputation outside France (where he always enjoyed high esteem) did begin to diminish during the 18th century, and remained low thereafter.

have begun to argue that the originality and unity of his philosophical system merits him a place alongside such figures as Descartes, Spinoza, and Leibniz.

In addition, the Conversations chrétiennes were translated in 1695 as Christian Conferences... to which is added, Meditations on Humility and Repentance: this work has also been unavailable in English since the seventeenth century.