[B]y the term “Universe,” … I mean to designate the utmost conceivable expanse of space, with all things, spiritual and material, that can be imagined to exist within the compass of that expanse.

Let us begin, then, at once, with that merest of words, “Infinity.” … It stands for the possible attempt at an impossible conception.

[Y]ou can easily understand how restrictions so absurd on their very face must have operated, in those days, to retard the progress of true Science, which makes its most important advances — as all History will show — by seemingly intuitive leaps.