Freedom of Will:
In the field of ethics, reason can not explain either the basis of morality or its postulates. Freedom of will is a fundamental postulate of ethics. In all the means volition is controlled by external nature then morality does not have any meaning. “Thou oughtst, therefore, thou canst.” This is what Kant’s words implied.
Immortality of Soul;
According to Kant, the second postulate of ethics is the immortality of the soul. Morality lies in winning the continuous struggle between desire and duty not this activity is so difficult that it seems well nigh impossible to complete it in one limited life.
Thus in the absence of many lives, the very impossibility of the attainment of the aim of morality is undermined. Consequently, it is indispensable to recognise that the soul does not perish with the body but rather continues by assuming other bodies.
Faith in the existence of God:
In Kant’s opinion the third moral postulate is the faith in the existence of God. In the world we see that the result of morality is not always good but rather it is often the bad people who flourish.
As Kant pointed, perfect good comes after the assimilation of virtue and happiness. Thus if a virtuous person suffers in this world and moral laws are true at the sometime, it is then necessary to concede that goodwill grant them happiness in another world.
Thus, God establishes complete good by adjusting between virtue and happiness and maintains morality by giving to man according to his desires. In this way, according to Kant there are three postulates of morality- freedom of will, immortality of soul and existence of God.
According to Kant, it is virtue which is the ultimate end. Morality is the supreme or highest good. In the words of Kant, “There is nothing in the world, or even out of it, that can be called good without qualification, except goodwill.” Goodwill is the one Jewel which shines and glories in its own light. According to Kant, virtue is good will. Thus the ultimate end is the doing of duty for the sake of duty. But according to Kant the complete moral aim is our own perfection and an addition to other people’s happiness. That is also the Corollary of Kant’s second moral maxim. This is the reason why Kant recognises the existence of God a moral postulate. .
Freedom of the Individual:
A man is free in the form of a moral being. Man is autonomous. Thus, his aim is to be self-controlled. Man is, on the one hand, a sensible being and an intellectual one on the other.
Reason and sensation are the highest and the lowest parts of man. The senses always cure man in their own direction and act as if blind, but his moral consciousness always reminds him of his intrinsic freedom from the passions.
Thus a struggle between the reason and the passions goes on. According to Kant, the morality of the volition will be as great as the intensity of the struggle. Freedom lies in acting in accordance with the internal intellectual soul having triumphed over the lower soul and this is also the aim of a moral life. Goodwill is a rational will. It applies its own law upon itself. Volition should proceed on categorical imperative. To proceed according to reason is freedom and dependence to follow emotion.