It is in the common interest not only that crimes not be committed, but that they be rarer in proportion to the harm they do to society. Hence the obstacles which repel men from committing crimes ought to be made stronger the more those crimes are against the public good and the more inducements there are for committing them. Hence, there must be a proportion between crimes and punishments.

It is impossible to foresee all the mischiefs which arise from the universal struggle of the human emotions. They multiply at a compound rate with the growth of population and with the criss-crossing of private interests, which cannot be geometrically directed towards the public utility. In political arithmetic, we must substitute the calculus of probabilities for mathematical exactitude. {{Even a cursory look at history shows that disorder grows as the boundaries of empires expand. As patriotic sentiment correspondingly wanes, there is a growth in the motives for crime insofar as each individual has an interest in that very disorder: therefore, the need to stiffen the punishments continually increases.}}

That force which attracts us, like gravity, to our own good can be controlled only by equal and opposite obstacles. The effects of this force are the whole confused gamut of human actions: if these interfere with and obstruct one another, then the punishments, which we may call political obstacles, eliminate their evil effects, without destroying the moving cause, which is the very sensibility inalienable from man's nature.