[Footnote 103: This presumption, founded upon age alone, is as absurd in civil matters as in criminal. What can be more entirely ludicrous than the idea that all men (not manifestly imbecile) become mentally competent to make all contracts whatsoever on the day they become twenty-one years of age?--and that, previous to that day, no man becomes competent to make any contract whatever, except for the present supply of the most obvious wants of nature? In reason, a man's _legal_ competency to make _binding_ contracts, in any and every case whatever, depends wholly upon his _mental_ capacity to make _reasonable_ contracts in each particular case. It of course requires more capacity to make a reasonable contract in some cases than in others. It requires, for example, more capacity to make a reasonable contract in the purchase of a large estate, than in the purchase of a pair of shoes. But the mental capacity to make a reasonable contract, in any particular case, is, in reason, the only legal criterion of the legal competency to make a binding contract in that case. The age, whether more or less than twenty-one years, is of no legal consequence whatever, except that it is entitled to some consideration as _evidence of capacity_. It may be mentioned, in this connection, that the rules that prevail, that every man is entitled to freedom from parental authority at twenty-one years of age, and no one before that age, are of the same class of absurdities with those that have been mentioned. The only ground on which a parent is ever entitled to exercise authority over his child, is that the child is incapable of taking reasonable care of himself. The child would be entitled to his freedom from his birth, if he were at that time capable of taking reasonable care of himself. Some become capable of taking care of themselves at an earlier age than others. And whenever any one becomes capable of taking reasonable care of himself, and not until then, he is entitled to his freedom, be his age more or less. These principles would prevail under the true trial by jury, the jury being the judges of the capacity of every individual whose capacity should be called in question.] [Footnote 104: In contrast to the doctrines of the text, it may be proper to present more distinctly the doctrines that are maintained by judges, and that prevail in courts of justice.