“ In making such a reflection we are not opposing physical considerations to moral, but moral to physical; we are seeking to make the voice of reason heard, which drives us back from the extravagance of sentimentalism on common sense. ”
 Plato, The Republic. copy citation

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“When again in private life we see a whole family one by one dropping into the grave under the Ate of some inherited malady, and the parents perhaps surviving them, do our minds ever go back silently to that day twenty-five or thirty years before on which under the fairest auspices, amid the rejoicings of friends and acquaintances, a bride and bridegroom joined hands with one another? In making such a reflection we are not opposing physical considerations to moral, but moral to physical; we are seeking to make the voice of reason heard, which drives us back from the extravagance of sentimentalism on common sense. The late Dr. Combe is said by his biographer to have resisted the temptation to marriage, because he knew that he was subject to hereditary consumption. One who deserved to be called a man of genius, a friend of my youth, was in the habit of wearing a black ribbon on his wrist, in order to remind him that, being liable to outbreaks of insanity, he must not give way to the natural impulses of affection: he died unmarried in a lunatic asylum.” source