That kings should philosophise, or philosophers become kings, is not to be expected. But neither is it to be desired; for the possession of power is inevitably fatal to the free exercise of reason. But it is absolutely indispensable, for their enlightenment as to the full significance of their vocations, that both kings and sovereign nations, which rule themselves in accordance with laws of equality, should not allow the class of philosophers to disappear, nor forbid the expression of their opinions, but should allow them to speak openly. And since this class of men, by their very nature, are incapable of instigating rebellion or forming unions for purposes of political agitation, they should not be suspected of propagandism. APPENDIX I ON THE DISAGREEMENT BETWEEN MORALS AND POLITICS WITH REFERENCE TO PERPETUAL PEACE In an objective sense, morals is a practical science, as the sum of laws exacting unconditional obedience, in accordance with which we _ought_ to act. Now, once we have admitted the authority of this idea of duty, it is evidently inconsistent that we should think of saying that we _cannot_ act thus. For, in this case, the idea of duty falls to the ground of itself; “_ultra posse nemo obligatur_.” Hence there can be no quarrel between politics, as the practical science of right, and morals, which is also a science of right, but theoretical. That is, theory cannot come into conflict with practice. For, in that case, we would need to understand under the term “ethics” or “morals” a universal doctrine of expediency, or, in other words, a theory of precepts which may guide us in choosing the best means for attaining ends calculated for our advantage. This is to deny that a science of morals exists. Politics says, “Be wise as serpents”; morals adds the limiting condition, “and guileless as doves.” If these precepts cannot stand together in one command, then there is a real quarrel between politics and morals.[147] But if they can be completely brought into accord, then the idea of any antagonism between them is absurd, and the question of how best to make a compromise between the two points of view ceases to be even raised. Although the saying, “Honesty is the best policy,” expresses a theory which, alas, is often contradicted in practice, yet the likewise theoretical maxim, “Honesty is better than any policy,” is exalted high above every possible objection, is indeed the necessary condition of all politics. [147] Cf. Aristotle: _Politics_, (Welldon’s trans.) IV. Ch. XIV. “The same principles of morality are best both for individuals and States.”