Having for their object the Science of Man, present difficulties exceedingly great, and, to merit confidence, must be collected upon a scale far too … - Adolphe Quetelet

The tables of criminality for different ages, given in my published treatise, merit at least as much faith as the tables of mortality, and verify themselves within perhaps even narrower limits; so that crime pursues its path with even more constancy than death. ...it is still betwixt the ages of twenty-one and twenty-five, that, all things being equal, the greatest number of persons are to be found in that position [of a criminal].

The progressive development of moral and intellectual man has scarcely occupied their [scientists] attention; nor have they noted how the faculties of his mind are at every age influenced by those of the body, nor how his faculties mutually react.

The more advanced the sciences have become, the more they have tended to enter the domain of mathematics, which is a sort of center towards which they converge. We can judge of the perfection to which a science has come by the facility, more or less great, with which it may be approached by calculation.