“If the study to which you apply yourself has a tendency to weaken your affections and to destroy your taste for those simple pleasures in which no alloy can possibly mix, then that study is certainly unlawful, that is to say, not befitting the human mind.”

“A human being in perfection ought always to preserve a calm and peaceful mind and never to allow passion or a transitory desire to disturb his tranquility. I do not think that the pursuit of knowledge is an exception to this rule. If the study to which you apply yourself has a tendency to weaken your affections and to destroy your taste for those simple pleasures in which no alloy can possibly mix, then that study is certainly unlawful, that is to say, not befitting the human mind. If this rule were always observed; if no man allowed any pursuit whatsoever to interfere with the tranquillity of his domestic affections, Greece had not been enslaved, Caesar would have spared his country, America would have been discovered more gradually, and the empires of Mexico and Peru had not been destroyed.”

“A mind of moderate capacity which closely pursues one study must infallibly arrive at great proficiency in that study.”

“Even where the affections are not strongly moved by any superior excellence, the companions of our childhood always possess a certain power over our minds which hardly any later friend can obtain. They know our infantine dispositions, ...; and they can judge of our actions with more certain conclusions as to the integrity of our motives.”

“... the companions of our childhood always possess a certain power over our minds which hardly any later friend can obtain.”

“If, instead of this remark, my father had taken the pains to explain to me that the principles of Agrippa had been entirely exploded and that a modern system of science had been introduced which possessed much greater powers than the ancient, because the powers of the latter were chimerical, while those of the former were real and practical, under such circumstances I should certainly have thrown Agrippa aside and have contented my imagination, warmed as it was, by returning with greater ardour to my former studies. It is even possible that the train of my ideas would never have received the fatal impulse that led to my ruin.”

“My father looked carelessly at the title page of my book, and said, "Ah! Cornelius Agrippa! My dear Victor, do not waste your time upon this; it is sad trash." If, instead of this remark, my father had taken the pains to explain to me, that the principles of Agrippa had been entirely exploded, and that a modern system of science had been introduced, which possessed much greater powers than the ancient, because the powers of the latter were chimerical, while those of the former were real and practical; under such circumstances, I should certainly have thrown Agrippa aside, and, with my imagination warmed as it was, should probably have applied myself to the more rational theory of chemistry which has resulted from modern discoveries”