What the engineer is to the mathematician, the active statesman is to the contemplative statesman.

It is indeed most important that legislators and administrators should be versed in the philosophy of government, as it is most important that the architect, who has to fix an obelisk on its pedestal, or to hang a tubular bridge over an estuary, should be versed in the philosophy of equilibrium and motion.
But, as he who has actually to build must bear in mind many things never noticed by D'Alembert and Euler, so must he who has actually to govern be perpetually guided by considerations to which no allusion can be found in the writings of Adam Smith or Jeremy Bentham.

The perfect lawgiver is a just temper between the mere man of theory, who can see nothing but general principles, and the mere man of business, who can see nothing but particular circumstances.

Of lawgivers in whom the speculative element has prevailed to the exclusion of the practical, the world has during the last eighty years been singularly fruitful.
To their wisdom Europe and America have owed scores of abortive constitutions, scores of constitutions which have lived just long enough to make a miserable noise, and have then gone off in convulsions.

But in the English legislature the practical element has always predominated, and not seldom unduly predominated, over the speculative.