Of a truth, it is purely a matter of accident that an individual should have received from nature a larger or smaller amount of mental vigour. This amount, always an unknown quantity to him, is in no way dependent on him, and is just so much as nature has bestowed, not a fraction more. How, then, can any one prudently abandon himself to the guidance of his reason alone? Is not this the same as committing one's destinies to blind chance? Some may perhaps wonder at my saying that the amount of our own mental vigour "is always an unknown quantity to us, and in no way dependent on us;" yet, singular as it may appear, it is none the less a simple, undeniable fact.
The power of the instrument by which we know all other things always remains, and by the nature of the case must always remain, hidden from our knowledge. We cannot measure the power of our intelligence. How could we do so except by means of another intelligence? And if there are two intelligences in us (an absurd thing to say) by what will the power of the second be measured ?
Antonio Rosmini, Theodicy, volume 1, Signini et al, tr., p. 34.