It is therefore important to understand first off Aristotle's thoughts on human nature in order to understand his opinions on ethics and virtue. That human beings are social beings is something familiar to us nowadays as it was in Aristotle's time. Consequently, ethics and virtue were part of human nature and so every living being was supposed to live by what is righteous. This is another characteristic separating us from animals.
Thus, humans being sociable persons and living within a society, politics also had to implement rules and regulations that would help people. But it didn't necessarily mean that a man who did right things and lived by the rules was essentially virtuous because he was in fact constraint to do so. Therefore, to Aristotle, someone who did right things because of the wrong reasons was not at all virtuous. The virtuousness only applied if that person acted because of his own moral beliefs and lifestyle. Politics was then the institution that allowed people to "live well" which does not apply today anymore, since politics hardly has anything to do with morals. if, in ancient times, politics was considered a royal art or as the science of ruling, today such a vision is an utopia.
In the Nicomachean Ethics, Aristotle focuses on the progression of human beings towards reaching an ideal human pattern of existence related to human's own involvement in the process. But there is never an end to the process, meaning the human being is conditioned to always search for that ideal, a paradox I would say, since the process is continuous and the concept of something idealistic usually concerns a closure.
The choice is therefore at anyone's reach and it marks the decisive moment of materializing the moral intention, the rational process. Therefore, happiness has to be understood in relation to the soul's activity and acts of virtues. Aristotle reduces happiness to a mere act of confirmation and development of that which applies to human beings. And happiness requires intelligence as part of the thinking process. It is through our own rationality that we acquire virtue and happiness.
The supremacy of perfection was God, Aristotle believed. Perfection being the result of evolution, happiness cat be obtained in a step-by-step process along with one's evolution. According to it, matter adapts faster and faster, finally reaching towards perfection as God. Therefore, there is such a thing as intellectual happiness, as resulted from pure rationality. This was Aristotle's second view of virtue. But although intellectual happiness could relieve suffering, it never could have end it because happiness was by far an emotion that needed to be treated otherwise than objective.
Having responded so far to the first part of the question (what does Aristotle understand by ethics?), let us examine now how important his view of humanity is to ethics. Part of his understanding on human nature was about the good character and that people were born with such a capacity; it was therefore human nature to be good. But although a capacity, it took practice for man to develop his nature. And man did so through his actions or dispositions.
In his Nicomachean Ethics, Aristotle says all of the species have their own nature and that the only way for the species to "live well" is to fulfill their nature. As already mentioned, he concluded that man has both a rational part and an irrational part and that human beings are indisputable sociable human beings. Therefore, man taken together with all of his parts and all of his functions can only achieve happiness when having the ability to fulfill these drives. This then is Aristotle's opinion in regards to human nature and humanity.
What Aristotle teaches us is that humans have free will, the free will to initiate a process of development that eventually leads to one becoming virtuous. and, like everything else around us, we are influenced by what we do, by how we do it and by what our thoughts perceive of the surrounding environment. But man is of duality, he is also the subject of impulses and pleasures, thus often deviating from his course. It is here where virtue and ethics come into place, at the moment between the extremes where man has to acknowledge his righteous condition. Thus, we have to go against our nature to become virtuous, we must learn self-control to achieve moral standards.
Thus, Aristotle's view of humanity is quite important to ethics because it leaves people always with the possibility of choice. Furthermore, it implements a behavioural pattern which humans can use to understand their course of action and take over a new perspective. Many of Aristotle's theories apply today, as well, maybe even more today than it did in ancient times because humanity seems to be more and more in debt to a sense of responsibility towards its own actions and attitudes. And although moral values and beliefs circulate worldwide and one which is Western might not apply to Europe or Occident, the foundation is understood by every human being. People might be good by nature but they are only moral by practice. And yes, morality differs largely from what it meant say, fifty years ago, but this is why ethics is a science and this is why Aristotle said it was a teachable one, a form of art, because it is a duty of man to learn about…