What is Kant’s doctrine of moral reasoning?

[Jurisprudence] Kant conceived the law of nature as a principle of human reason kind of rational system capable of rational deductions on ethical lines. According to him, the law of reason is a purely logical category not influenced by external factors or ends or empirical choices or experiences. Law of reason is a moral imperative-it is categorical, obligatory in the form of command directing the human will to do what is morally good for all times and places irrespective of ends.