Aspects of Kant's ethics relating to philosophy of religion

Kant's doctrine of the postulates of the immortality of the soul and the existence of God has not always been appreciated in modern times; easily one can incline to the opinion that this doctrine is a throw-back into dogmatic metaphysics or an attempt to harmonize Kant's ethics with central tenets of the Christian religion. In the article it is argued that the postulates mentioned are not superfluous in ethical respect but an integral part of Kant's moral philosophy. Otherwise there would be a deficiency of reason in Kant's theory of duty. A rational being cannot in theory totally neglect the natural human desire of happiness. If there were no reason of believing in the possibility of virtue rewarded after death, one could not understand oneself as a rational actor in following strictly the rigid command of duty how perilous the situation might be without any prospect of advantage neither for oneself nor for other human beings. The doctrine of the postulates is not of practical but of theoretical importance. It points out to an external rational order in the destiny of human beings and is related to Kant's teleological philosophy of history and religion.