I am aware of how abstruse all this reasoning must appear to the general run of readers—people who aren’t accustomed to going so deeply into the intellectual faculties of the mind, and so will be apt to reject as fanciful anything that doesn’t fit with common received notions and with the easiest and most obvious principles of philosophy. You do have to take some trouble to follow these arguments of mine, though it takes very little trouble to see to see ·how bad the rival accounts are·—to see the imperfection of every plain-man hypothesis on this subject, and how little light philosophy has so far been able to cast in these elevated and challenging inquiries. If you can once be fully convinced that
•Nothing in any object, considered in itself, can give us a reason for drawing a conclusion about anything other than that object, and
•Even after observing the frequent or constant conjunction of objects, we have no reason to draw any inference about any object other than those of which we have had experience,
these two principles will throw you so loose from all common systems that you will have no trouble accepting other theses that may appear very extraordinary. These principles proved to be sufficiently convincing when applied to our most certain reasonings from causation; but I venture to say that they become even more believable when applied to the conjectural or probable reasonings that are our present topic.