1) Human nature: According to me, the theory of utilitarianism which emphasized on reasoning about feelings of pleasure and pain is more accurate or useful in characterizing human nature more than the theory of Kant which emphasized on human rationality alone. It is more accurate because it explains things that are seen clearly and are basic in determining the nature of humans because with no pain there is a pleasure and with no pleasure there is a pain. When there is no pain, there is happiness, and when there is no pleasure, there is unhappiness.
Happiness is the only thing with inherent value, and it is determined by pain and pleasure, so it is not possible to remove pleasure and pain when discussing value. Because value is measured by happiness which is measured by the level of pain or pleasure hence, all these are connected and when one is eliminated the whole thing becomes impossible to explain and show something real.
2) Deity: It is helpful to a religion to understand as Kant did; that human minds are not capable of knowing God and our knowledge have limits because it is true and the sooner one accepts thing, the more important it is for him to look at what he can understand about God and not what he cannot because he will never understand. Kant’s view does not silence theologians it just moves the conversation to another level because even if we cannot understand God, we are obliged to teach and learn the knowledge we are capable of understanding about God.
3) Ethics: I find myself using the theory of Bentham & Mills of utilitarianism under various circumstances, for instance, I work hard every day to maintain the level of pleasure high and to keep it last long so as to continue being happy because when pleasure reduces there is pain which is unhappiness something everyone does not want. The other weaknesses which I noted on the theories are that the theories cannot answer each question asked about what it proves.
4) Kant killed metaphysics by changing it to the critique of pure reasoning. This killed metaphysics because no one concentrated on it and they had something new.
I agree that what is real is forever unknowable, and it will always be tainted by human categories, frameworks and ways of looking at reality. This is because no one understands what is real, and for them to study what is real they have to come up with theories which will be tested and if it gives good feedbacks they research more on it. When they do not find the answer, they criticize what is real instead of leaving the methods they used to search for it and use other methods without giving up. What is real will always be tainted because when people do not find it, and they know they are not capable of finding it they term it as a bad thing instead of accepting the limitations they have towards acquiring knowledge.