Note 314 — Chapter IV

We often hear of hereditary talents, hereditary vices, and hereditary virtues; but whoever will critically examine the evidence will find that we have no proof of their existence. The way in which they are commonly proved is in the highest degree illogical; the usual course being for writers to collect instances of some mental peculiarity found in a parent and in his child, and then to infer that the peculiarity was bequeathed. By this mode of reasoning we might demonstrate any proposition; since in all large fields of inquiry there are a sufficient number of empirical coincidences to make a plausible case in favour of whatever view a man chooses to advocate. But this is not the way in which truth is discovered; and we ought to inquire not only how many instances there are of hereditary talents, &c. but how many instances there are of such qualities not being hereditary. Until something of this sort is attempted, we can know nothing about the matter inductively: while, until physiology and chemistry are much more advanced, we can know nothing about it deductively.

These considerations ought to prevent us from receiving statements (Taylor's Medical Jurisprudence, pp. 644, 678, and many other books) which positively affirm the existence of hereditary madness and hereditary suicide; and the same remark applies to hereditary disease (on which see some admirable observations in Phillips on Scrofula, pp. 101–120, London, 1846); and with still greater force does it apply to hereditary vices and hereditary virtues; inasmuch as ethical phenomena have not been registered as carefully as physiological ones, and therefore our conclusions respecting them are even more precarious.