If this be not allowed a valid objection, all conjectures are alike, and all equally philosophical.

I own it appears to me that in the train of our present observations, there are no more genuine indications that man will become immortal upon earth than that he will have four eyes and four hands, or that trees will grow horizontally instead of perpendicularly.
It will be said, perhaps, that many discoveries have already taken place in the world that were totally unforeseen and unexpected.

This I grant to be true; but if a person had predicted these discoveries without being guided by any analogies or indications from past facts, he would deserve the name of seer or prophet, but not of philosopher.
The wonder that some of our modern discoveries would excite in the savage inhabitants of Europe in the times of Theseus and Achilles, proves but little.

Persons almost entirely unacquainted with the powers of a machine cannot be expected to guess at its effects.

I am far from saying, that we are at present by any means fully acquainted with the powers of the human mind; but we certainly know more of this instrument than was known four thousand years ago; and therefore, though not to be called competent judges, we are certainly much better able than savages to say what is, or is not, within its grasp.