46. It is a recognised axiom of natural philosophy, that nothing falls within the scope of the senses unless it is subjected to their observation, as for instance an object placed before the eyes, or an event posterior to the birth of human sense and intelligence. The former we can see and handle, and therefore the mind is qualified to pass a verdict upon it, since it can be examined by the senses of touch and sight. The latter, which is an event in time, produced or constituted since the origin of man, falls within the limits in which the discerning sense may claim to pass judgment, since it is not prior in time to our perception and reason. For our sight cannot perceive the invisible, since it only distinguishes the seen; our reason cannot project itself into the time when it was not, because it can only judge of that, to which it is prior in time. And even within these limits, the infirmity which is bound up with its nature robs it of absolutely certain knowledge of the sequence of cause and effect. How much less then can it go back behind the time when it had its origin, and comprehend with its perception things which existed before it in the realms of eternity?