Such is the regularity we expect to find, if the actions of men are governed by the state of the society in which they occur; while, on the other hand, if we can find no such regularity, we may believe that their actions depend on some capricious and personal principle peculiar to each man, as free will or the like. It becomes, therefore, in the highest degree important to ascertain whether or not there exists a regularity in the entire moral conduct of a given society; and this is precisely one of those questions for the decision of which statistics supply us with materials of immense value.
For the main object of legislation being to protect the innocent against the guilty, it naturally followed that European governments, so soon as they became aware of the importance of statistics, should begin to collect evidence respecting the crimes they were expected to punish. This evidence has gone on accumulating, until it now forms of itself a large body of literature, containing, with the commentaries connected with it, an immense array of facts, so carefully compiled, and so well and clearly digested, that more may be learned from it respecting the moral nature of Man than can be gathered from all the accumulated experience of preceding ages.[22] But as it will be impossible in this Introduction to give anything like a complete statement of those inferences which, in the actual state of statistics, we are authorized to draw, I shall content myself with examining two or three of the most important, and pointing out the connexion between them.
[22] I say this advisedly: and whoever has examined these subjects must be aware of the way in which writers on morals repeat the commonplace and hackneyed notions of their predecessors; so that a man, after reading everything that has been written on moral conduct and moral philosophy, will find himself nearly as much in the dark as when his studies first began. The most accurate investigators of the human mind have hitherto been the poets, particularly Homer and Shakespeare; but these extraordinary observers mainly occupied themselves with the concrete phenomena of life; and if they analyzed, as they probably did, they have concealed the steps of the process, so that now we can only verify their conclusions empirically. The great advance made by the statisticians consists in applying to these inquiries the doctrine of averages, which no one thought of doing before the eighteenth century.