This is our true state; this is what makes us incapable of certain knowledge and of absolute ignorance. We sail within a vast sphere, ever drifting in uncertainty, driven from end to end. When we think to attach ourselves to any point and to fasten to it, it wavers and leaves us; and if we follow it, it eludes our grasp, slips past us, and vanishes for ever. Nothing stays for us. This is our natural condition, and yet most contrary to our inclination; we burn with desire to find solid ground and an ultimate sure foundation whereon to build a tower reaching to the Infinite. But our whole groundwork cracks, and the earth opens to abysses.
Let us therefore not look for certainty and stability. Our reason is always deceived by fickle shadows; nothing can fix the finite between the two Infinites, which both enclose and fly from it.
If this be well understood, I think that we shall remain at rest, each in the state wherein nature has placed him. As this sphere which has fallen to us as our lot is always distant from either extreme, what matters it that man should have a little more knowledge of the universe? If he has it, he but gets a little higher. Is he not always infinitely removed from the end, and is not the duration of our life equally removed from eternity, even if it lasts ten years longer?
In comparison with these Infinites all finites are equal, and I see no reason for fixing our imagination on one more than on another. The only comparison which we make of ourselves to the finite is painful to us.
If man made himself the first object of study, he would see how incapable he is of going further. How can a part know the whole? But he may perhaps aspire to know at least the parts to which he bears some proportion. But the parts of the world are all so related and linked to one another, that I believe it impossible to know one without the other and without the whole.
Man, for instance, is related to all he knows. He needs a place wherein to abide, time through which to live, motion in order to live, elements to compose him, warmth and food to nourish him, air to breathe. He sees light; he feels bodies; in short, he is in a dependent alliance with everything. To know man, then, it is necessary to know how it happens that he needs air to live, and, to know the air, we must know how it is thus related to the life of man, etc. Flame cannot exist without air; therefore to understand the one, we must understand the other.
Since everything then is cause and effect, dependent and supporting, mediate and immediate, and all is held together by a natural though imperceptible chain, which binds together things most distant and most different, I hold it equally impossible to know the parts without knowing the whole, and to know the whole without knowing the parts in detail.
[The eternity of things in itself or in God must also astonish our brief duration. The fixed and constant immobility of nature, in comparison with the continual change which goes on within us, must have the same effect.]
And what completes our incapability of knowing things, is the fact that they are simple, and that we are composed of two opposite natures, different in kind, soul and body. For it is impossible that our rational part should be other than spiritual; and if any one maintain that we are simply corporeal, this would far more exclude us from the knowledge of things, there being nothing so inconceivable as to say that matter knows itself. It is impossible to imagine how it should know itself.
So if we are simply material, we can know nothing at all; and if we are composed of mind and matter, we cannot know perfectly things which are simple, whether spiritual or corporeal. Hence it comes that almost all philosophers have confused ideas of things, and speak of material things in spiritual terms, and of spiritual things in material terms. For they say boldly that bodies have a tendency to fall, that they seek after their centre, that they fly from destruction, that they fear the void, that they have inclinations, sympathies, antipathies, all of which attributes pertain only to mind. And in speaking of minds, they consider them as in a place, and attribute to them movement from one place to another; and these are qualities which belong only to bodies.