Before we start our discussion on Ethical Theories of Aristotle (384 – 322 BCD) and Kant (1724 – 1804) and discuss the nature of reason and its role in ethics we should determine what is the word ''ethics'' itself?
The first definition of ethics is produced as the presence of values and customs instantiated in the lives of particular groups of human beings is referred to as the ethics of these groups. Philosophers may concern themselves with describing these systems, but this is normally considered as the task of anthropology. Secondly, the term ''ethics'' is used to refer to one in particular of these systems, ‘morality’, which involves notions such as rightness and wrongness, guilt and shame etc.
Plato used the word ''politics'' for ethical inquiry whereas Aristotle described it in the form of some questions as what is justice. what is virtue? What is a good human being? What is an ideal life? How should one live? Etc. Aristotle was soon able to make distinction between two classes of human excellence or virtue - the first one called the intellectual and other class was called ethical.
Ethical is the application of practical reason. According to Aristotle humanity is distinct in our power to reason alone and morality is not an inborn quality, in fact, it is learnt by human beings from a chain of events. Perception or idea is stored as memory and groups of memory are stuck together to form a series of subjective experience that provides us the general understanding of World existing around us, which Aristotle explained as Morality. Morality is the set of rules that apply to the world, as we know it. Aristotle later on referred ethics ''typical or customary'' as in dwelling places of humans or animals but he was more concerned with examining what is customary or characteristics in the life of an individual and specifically the distinctive characteristics of individual or the state of his soul which is directive to act in specific ways.
Aristotle starts developing the concept of ethics by taking into account two important aspects of human conduct directly related to pleasure and pain.
(1) Temperance - which is related to food, drinks and sex.
(2) Courage - which is related to fear of bodily injury or death.
Thereafter he examines Passion and says that when we experience passion - we are passive hence we undergo a change that acts on us. That change is partly to our body and partly to our soul. Kant disagrees with this theory as saying this ''not-evident'' - although Kant did claim Aristotle''s first claim to be true but by an entirely different mechanism. Kant says all moral judgments must be examined by a priori. The conceptions of morality can not be discovered through experience or exercise of reason alone - these are completely independent of World around us.
Kant says that principles having effects on human behavior must be synthetic instead of analytic, a priori instead of posteriori and rational instead of epical for ethics and they can not be derived from experience. As moral judgments are independent of the world as it exists, they should be regarded as priori. Kant then suggested that happiness might indeed conflict with something beyond itself, reason and that inclination and duty may provide conflicting consideration. According to Kant, the moral worth of an action lies not in its expected effect but from the duty upon which moral actions are engendered. The duty of individual is determined by Rational Principles which Kant calls the Categorical Imperative i.e. one should act only in accordance with duty and one knows that doing such and such is one''s duty if and only if one is willingness to allow everyone to do such and such and one feels that doing such and such should be an unconditional universal law binding on the will of every rational person. A categorical imperative is a command, which does possess universality and as such is not rests. Some examples are suicide, promise to repay a debt, ignoring one''s talent and not helping others and similarly other negative attitudes of human personality. In Hypothetical Imperative, it''s a command in the form of hypothetical proposition and normally mentions some specific reason - for example if you wish to pass the exam then you should study regularly. According to Kant such imperatives can not be applied to morality as they may be predicated solely upon subjective inclination and not universal duty. Kant''s principle of respect for persons, have had a major role to play in the teaching of applied and professional ethics over the past several years.
Ethics plays an important role in every aspect of human life. Every department of life and its functionality is based on morality and its respective professional ethics. This is the professional ethics, which builds up the confidence between doctor and patient, lawyer and its clients, buyer and seller, journalism, nursing, business, sports, almost all areas of life.