Edward Bulwer Lytton 
The Caxtons [EPUB ebook] 

‘Sir-sir, it is a boy!’
‘A boy, ‘ said my father, looking up from his book, and evidently much puzzled: ‘what is a boy?’
Now my father did not mean by that interrogatory to challenge philosophical inquiry, nor to demand of the honest but unenlightened woman who had just rushed into his study, a solution of that mystery, physiological and psychological, which has puzzled so many curious sages, and lies still involved in the question, ‘What is man?’ For as we need not look further than Dr. Johnson’s Dictionary to know that a boy is ‘a male child, ‘-i.e., the male young of man, -so he who would go to the depth of things, and know scientifically what is a boy, must be able to ascertain ‘what is a man.’ But for aught I know, my father may have been satisfied with Buffon on that score, or he may have sided with Monboddo. He may have agreed with Bishop Berkeley; he may have contented himself with Professor Combe; he may have regarded the genus spiritually, like Zeno, or materially, like Epicurus. Grant that boy is the male young of man, and he would have had plenty of definitions to choose from.