Aristotle proposes using the mind in accordance with virtue to live a happy life. Kant proposes practical reason, not impulses or desires, to achieve the proper state of human existence.
Aristotle states that happiness isn’t physical pleasure, but harmonizing the mind with virtue. What feels the best for the most is virtue. The intellectual and emotional parts of the mind create intellectual and moral types of virtue. This virtue is expressed from the mind by voluntary action.
Aristotle proposes choosing the "Golden Mean" between too much emotion and too much action. Courage is virtuous when it balances between cowardice and rashness, extravagance and indifference. Justice occurs when each person gets what he deserves. Any departure from the mean is injustice.
Aristotle states that a life of ultimate happiness and fulfillment is a life of solitary contemplation. However, he suggests that this state of being can’t be realized by mere mortals. He argues that the greatest happiness can be achieved by following moral values to live a busy life of politics and public splendor.
Kant’s moral philosophy proposes that practical reason in accordance with moral imperatives should drive right actions. Duty should guide right action. Acting according to what is willed to be universal law is the “Categorical Imperative” that should guide behavior. Human beings are ends rather than the means to achieving the happiest possible life.