Reason instructs us that all our ideas must have some foundation of truth, for it could not be that the All-Perfect and the All-True should otherwise have put them into us; and because our reasonings are never so evident or so complete when we sleep as when we wake, although sometimes during sleep our imagination may be more vivid and positive, it also instructs us that such truth as our thoughts have will assuredly be in our waking thoughts rather than in our dreams.
V.—WHY I DO NOT PUBLISH “THE WORLD"
I have always remained firm in my resolve to assume no other principle than that which I have used to demonstrate the existence of God and of the soul, and to receive nothing which did not seem to me clearer and more certain than the demonstrations of the philosophers had seemed before; yet not only have I found means of satisfying myself with regard to the principal difficulties which are usually treated of in philosophy, but also I have remarked certain laws which God has so established in nature, and of which He has implanted such notions in our souls, that we cannot doubt that they are observed in all which happens in the world.
The principal truths which flow from these I have tried to unfold in a treatise ("On the World, or on Light"), which certain considerations prevent me from publishing. This I concluded three years ago, and had begun to revise it for the printer when I learned that certain persons to whom I defer had disapproved an opinion on physics published a short time before by a certain person [Galileo, condemned by the Roman Inquisition in 1633], in which opinion I had noticed nothing prejudicial to religion; and this made me fear that there might be some among my opinions in which I was mistaken.
I now believe that I ought to continue to write all the things which I judge of importance, but ought in no wise to consent to their publication during my life. For my experience of the objections which might be made forbids me to hope for any profit from them. I have tried both friends and enemies, yet it has seldom happened that they have offered any objection which I had not in some measure foreseen; so that I have never, I may say, found a critic who did not seem to be either less rigorous or less fair-minded than myself.