Kant

* Categorical imperative: for Kant the idea of moral obligation comes from within ourselves and we experience it as the categorical imperative.

Being moral was a case of following this categorical imperative. A genuinely moral action would be one that was done on the maxim which we could will to be a universal law.

* Our moral experience shows that we are under an obligation to achieve goodness or virtue, and not merely an average level of morality but the highest standard possible.

* We also recognise that true virtue should be rewarded by happiness for it would not be a rationally satisfying state of affairs if happiness came to the unvirtuous or unhappiness to the virtuous. If people were good but were also in pain and misery, their virtue would still be valuable but nevertheless the total situation would not be the best possible.

* The desired state of affairs in which man is both virtuous and happy is called by kant the "summum bonum" (highest good).

* But while humans can achieve bvirtue, it is clearly outside their power to ensure thst virtue is rewarded or coincides with happiness. So there is a God who who has the power to bring virtue and happiness into harmony. Such proportioning does not take place before death, so Kant argued that there must be survival after death.

Note that Kant was not arguing that morality IS INVALID IF God's existence is denied. For Kant the fact that it is a duty or obligation is sufficient reason to do it. But he thought that God was needed if the goal of morality was to be realised.