Kant makes the following remark on the purpose of reason: “For since reason is not sufficiently serviceable for guiding the will safely as regards its objects and the satisfaction of all our needs…its (reason’s) true function must be to produce a will which is good, not as a means to some further end”. According to this Kant perceives reason as a mean to produce good will, the unconditional good that ensure morals. His reasoning can be summarized as follow:1.Everything in nature work in a purposive manner. 2.It is not a purpose for reason to create a will satisfying all our needs. 3.Reason has influence on our will. With premise 1 and that reason exists, one derives that reason has a purpose. Given this and premise 2, 3, one may concludes that reason purposefully influence our will, but not for satisfying our needs. Kant claims that this purpose of reason is to produce good will. However premise 1 could be problematic, and if one is to follow Hume’s view of knowledge, that one ought to proportion trust in claims according to the strength of evidence, then 1 is clearly flawed. Despite how many things we have studied, we can only find purposes in finite number of things, never enough evidence to justify a claim infinite. If 1 is to limited to a number of things in nature, excluding reason, then the argument would not be valid. Alternatively we may simply define will guided solely by reason, free from inclination, as good will, although this will make the idea of a good will irreverent to experiences or common sense, for reason is considered a prior by Kant.
Under Kant’s definition of good will Abraham making attempt on Issac’s life is certainly not an act with good will, and hence an immoral act. Abraham’s act is unreasonable: he cannot provide a reason to others why he would try to kill his son, and in the end all he show through the event is obedience without using one’s own capacity to reason, effectively prevent any possibility for good will. Was there any reasoning for the universal which Abraham could use to justify his act, he should be able to communicate it to others, for reason is the same to all human. Would Abraham use reason to judge his action, he must see that one should not kill another person, for this cannot be an universal law: if everyone is to kill another person, there would be no human left to kill or to be killed.