We must be careful to distinguish between the "insoluble difficulties" which arise out of the imperfection of language adequate to give a formal description of a thing, and which may lead us to suppose ourselves involved in contradictions, and the "insoluble difficulties" which may arise out of the impossibility of having a mental representation of that thing. The latter is the only difficulty about which we need concern ourselves; and the best way to test the supposed difficulty as an insuperable one is to take one of the illustrations used by Mr. Spencer--the idea of space. We measure a foot or a mile of space, and then compare it with the idea of endless or (to us) immeasurable space. Figures afford us the means of expressing in language a certain definite number of miles of space, but, beyond the highest figures of which we have definite forms of expression, we can not go in definite descriptions of space. But when we have exhausted all the expressions of number that our arithmetical forms of expression admit, does it follow that we can not conceive of extension beyond that number? On the contrary, the very measure which we are able to express in figures, to a certain extent, in regard both to space and time, gives us the idea of space and time, and shows us that there must be an extension of both beyond and forever beyond the portion of either which language will allow us definitely to describe. This to us immeasurable and indescribable extent of space or time becomes a thinkable idea, because we are all the while thinking of space or time, whether it is a measurable portion of either, or an immeasurable and endless existence.