Strictly speaking, I am unaware of any thing that has a right to the title of an "impossibility" except a contradiction in terms. There are impossibilities logical, but none natural. A "round square," a "present past," "two parallel lines that intersect," are impossibilities, because the ideas denoted by the predicates, _round, present, intersect_, are contradictory of the ideas denoted by the subjects, _square, past, parallel_. But walking on water, or turning water into wine, or procreation without male intervention, or raising the dead, are plainly not "impossibilities" in this sense.
In the affirmation, that a man walked upon water, the idea of the subject is not contradictory of that in the predicate. Naturalists are familiar with insects which walk on water, and imagination has no more difficulty in putting a man in place of the insect than it has in giving a man some of the attributes of a bird and making an angel of him; or in ascribing to him the ascensive tendencies of a balloon, as the "levitationists" do. Undoubtedly, there are very strong physical and biological arguments for thinking it extremely improbable that a man could be supported on the surface of the water as the insect is; or that his organisation could be compatible with the possession and use of wings; or that he could rise through the air without mechanical aid. Indeed, if we have any reason to believe that our present knowledge of the nature of things exhausts the possibilities of nature, we might properly say that the attributes of men are contradictory of walking on water, or floating in the air, and consequently that these acts are truly "impossible" for him. But it is sufficiently obvious, not only that we are at the beginning of our knowledge of nature, instead of having arrived at the end of it, but that the limitations of our faculties are such that we never can be in a position to set bounds to the possibilities of nature. We have knowledge of what is happening and of what has happened; of what will happen we have and can have no more than expectation, grounded on our more or less correct reading of past experience and prompted by the faith, begotten of that experience, that the order of nature in the future will resemble its order in the past.