My basis is supported by the authority of the greatest moralist of modern times; for such, undoubtedly, J. J. Rousseau is,—that profound reader of the human heart, who drew his wisdom not from books, but from life, and intended his doctrine not for the professorial chair, but for humanity; he, the foe of all prejudice, the foster-child of nature, whom alone she endowed with the gift of being able to moralise without tediousness, because he hit the truth and stirred the heart.

What It Means

This is a placeholder explanation generated by the low-overhead model. It interprets "My basis is supported by the authority of the greatest moralist of modern times; for such, undoubtedly, J. J. Rousseau is,—that profound reader of the human heart, who drew his wisdom not from books, but from life, and intended his doctrine not for the professorial chair, but for humanity; he, the foe of all prejudice, the foster-child of nature, whom alone she endowed with the gift of being able to moralise without tediousness, because he hit the truth and stirred the heart." in the context of "Part III, Ch. VIII, 9, p. 230" to mean that wisdom is timeless.