"Do you believe nothing which is not capable of being tested by the ordinary rules which govern experience in things natural? How then do you know that you yourself exist? How do you know that the perceptions of your senses are not mere delusions, and that there is anything outside you answering to what your mind conceives? Have you a mind? and if you have not, what is it that enables you to think and reason, and fear, and hope? Are these conditions of your being the mere results of your material organism, like the headache which springs from indigestion, or the high spirits engendered by too much wine? Are you something better than a vegetable highly cultivated, or than your brothers of the lower animals? and, if so, what is it that differentiates your superiority? Why do things outside you obey your will? Who gave you a will? and, if so, what is it? I think you must allow that intellect is a thing almost divine, if there be anything divine; and I think also you must allow that it is not a thing to be propagated as we propagate well-made and high-bred cattle. Whence came Alexander the Great? Whence Charlemagne? And whence the First Napoleon? Was it through a mere process of spontaneous generation that they sprang up to alter by their genius and overwhelming will the destinies of the world? Whence came Homer, Shakespeare, Bacon? Whence came all the great historians? Whence came Plato and all the bright lights of divine philosophy, of divinity, of poetry? Their influence, after all, you must allow to be quite as wide and enduring as any produced by the masters of those positive material sciences which you worship. Do you think that all these great minds--for they are minds, and their work was not the product of a merely highly organised material frame--were the outcome of some system of material generation, which your so-called science can subject to rule, and teach men how to produce by growth, as they grow vegetables?"