What we know is not capable of being otherwise; of things capable of being otherwise we do not know, when they have passed outsideour observation, whether they exist or not. Therefore the object of knowledge is of necessity. Therefore it is eternal; for things that are of necessity in the unqualified sense are all eternal; and things that are eternal are ungenerated and imperishable.
In things which we know, everyone will trust us ... and we may do as we please, and no one will like to interfere with us; and we are free, and masters of others; and these things will be really ours, for we shall turn them to our good.
The necessity of knowing a little about a great many things is the most grievous burden of our day. It deprives us of leisure on the one hand, and of scholarship on the other.
Moreover, the works already known are due to chance and experiment rather than to sciences; for the sciences we now possess are merely systems for the nice ordering and setting forth of things already invented; not methods of invention or directions for new works.
Metaphysical world.- It is true, there could be a metaphysical world; the absolute possibility of it is hardly to be disputed. We behold all things through the human head and cannot cut off this head; while the question nonetheless remains what of the world would still be there if one had cut it off.