history, and, in particular, his strikingly close connexion with Rousseau.
The essay 'Perpetual Peace'—Zum ewigen Frieden—was published in 1795—the year of the Treaty of Basel. By that treaty Prussia finished her first war of the French Revolution. Only a visionary could have seen in the Treaty of Basel the star of hope in the sky. The treaty was a link in a chain that discredited Prussia in the eyes of Europe; and to the historian of international relations the treaty is noteworthy, inasmuch as it involved a surrender by Frederick William III of the system of the Empire and the system of Europe.
The highest of all practical problems for the human race, Kant declared, is the establishment of a Civil Society universally administering right according to law.[1] How can we institute and establish a Society in which liberty, under external laws, is combined in the greatest possible measure with irresistible power? It is the most difficult of problems: its perfect solution is not to be looked for, so crooked is the wood out of which men are carved. It will be the latest to find a practical solution, for the pre-requisites are of an exacting character—correct appreciation of the nature of a possible constitution; vast experience drawn from the practice of the ages, and especially a good will favourably disposed towards the reception of the solution.[2] These are conditions that will not be easily satisfied in combination, and if they are satisfied at all it will be late in the course of time and after many attempts have been made in vain to solve the problem—that of establishing a true Civil Society. We have to reckon with the 'unsocial sociability' of men. Their disposition to enter
