Ancient philosophy will always hold its own among those who are worthy to judge it, because it forms... a system that is solid and well articulated like the body, whereas all these scattered members of modern philosophy form no system.

We must admit, with the same frankness, that we are ignorant whether matter has in itself the faculty of feeling, or only the power of acquiring it by those modifications or forms to which matter is susceptible; for it is true that this faculty of feeling appears only in organic bodies.This is then another new faculty which might exist only potentially in matter, like all the others which have been mentioned; and this was the hypothesis of the ancients, whose philosophy, full of insight and penetration, deserves to be raised above the ruins of the philosophy of the moderns.

We know in bodies only matter, and we observe the faculty of feeling only in bodies: on what foundation then can we erect an ideal being, disowned by all our knowledge?

There comes up another difficulty which more nearly concerns our vanity: namely, the impossibility of our conceiving this property [the faculty of feeling] as a dependence or attribute of matter.

We have now but to prove a third attribute: I mean the faculty of feeling which the philosophers of all centuries have found in this same substance. ...[T]he Cartesians have made, in vain, to rob matter of this faculty. But in order to avoid insurmountable difficulties, they have flung themselves into a labyrinth from which they have thought to escape by this absurd system "that animals are pure machines."An opinion so absurd has never gained admittance among philosophers... Experience gives us no less proof of the faculty of feeling in animals than of feeling in men.

The Christian Scholastics... might have shown that God Himself said that He had "imprinted an active principle in the elements of matter (Gen. i; Is. lxvi).

Descartes, a genius made to blaze new paths and to go astray in them, supposed with some other philosophers that God is the only efficient cause of motion, and that every instant He communicates motion to all bodies. But this opinion is but an hypothesis which he tried to adjust to the light of faith; and in so doing he was no longer attempting to speak as a philosopher or to philosophers. Above all he was not addressing those who can be convinced only by the force of evidence.

If we demonstrate this moving principle, if we show that matter, far from being as indifferent as it is supposed to be, to movement and to rest, ought to be regarded as an active, as well as a passive substance, what resource can be left to those who have made its essence consist in extension?

The ancients, persuaded that there is no body without a moving force, regarded the substance of bodies as composed of two primitive attributes. It was held that, through one of these attributes, this substance has the capacity for moving and, through the other, the capacity for being moved.

Before Descartes, some of the ancients made the essence of matter consist in solid extension. But this opinion, of which all the Cartesians have made much, has at all times been victoriously combated...