lations. The eye knows nothing of sounds, of tastes, or of smells; each sense is shut up within itself.[1] Reason alone enables us to know the objective nature and the unchangeable relations of things; it is thus the only faculty by which moral distinctions can be cognized.[2]
It is clear from Cudworth's argument that reason is declared to be the faculty by which moral distinctions are perceived, because it alone is regarded as capable of discovering principles which are eternal and immutable. Cudworth feels that if moral laws are to be unconditionally valid, they must be dictates of reason. The rationalists of this period, however, are not content to remain at this stage. In their anxiety to establish morality on an absolutely firm foundation, they obliterate all distinction between the moral and the rational, between Right and Truth. Samuel Clarke is the representative of this point of view in its fully developed form.
According to Clarke, it is self-evident to a rational being that there are different necessary and eternal relations which different things bear to one another, and that from these relations there necessarily arises a fitness and unfitness in the application of different things to one another. It is also self-evident that in these circumstances an obligation is laid upon the rational being to act in I accordance with these eternal relations and fitnesses.[3] Reason, therefore, not only enables us to ascertain what is, but also to recognize how we ought to act. "By the reason of his mind, man cannot but be compelled to own and acknowledge that there is really such an Obligation indispensably incumbent upon him."[4] But the rational being, qua rational, not only perceives what he ought to do; he is also impelled to act in accordance with his sense of obligation. Reason is a motive power; it furnishes the impulse by means of which moral principles are realized in action. "And by this Understanding or Knowledge of the natural and necessary relations, fitnesses, and proportions of things, the Wills likewise of all Intelligent Beings are constantly directed, and must needs be deter-
