Book one of Aristotle’s Nicomachean Ethics is devoted to investigation of the nature of the good. As a former student of Plato, Aristotle used his teacher’s view towards the subject as the starting point of inquiry. However, his approach was different than Plato’s because he established the notion of direction of arguments being important for their outcomes. Aristotle’s idea was that arguments should lead up to fundamental principles but not proceed from them. This concept of directionality is also important in establishing a logical conclusion that there should be universal science in examining the good. Since in practice, Aristotle argued, such science does not exist and the good cannot be universal. He further extended his argument against Plato’s view of the universal good by inquiring whether a longer lasting good is more of a good than a temporary one. These three arguments are important in a broader context since they present a foundational structure for his concepts of morality and ethics in human life.
Aristotle’s first critique of Plato’s view of the good is that Plato failed to recognize that forms could be subject to development. This development involves the notions of priority and posteriority, since, according to Aristotle, concepts of quality and relatedness must be derived from substance of objects first. In that sense the good has to be first described for what it constitutes of and only then one can investigate its particular qualities. In general, comparing the qualities of different objects would reveal their “relatedness”, which suggests that good is not a single and universal entity, but rather a relationship encompassing various goods of different qualities. Therefore, Aristotle’s critique contrasts with Plato’s view of the good because it implies opposite direction for the approach of defining the good. In Plato’s Republic, the good was presented as the universal and unchangeable truth illuminating some representations of the forms. In that sense the good was independent and higher in hierarchy to the subjects it is related to. This signifies Plato’s top-down approach, where elements of human life are determined by the good and not the other way around. However, as described before, in Aristotle’s view, “good cannot be universal, common to all cases, and single” because various definitions of the good derive from different categories of substance.
Aristotle further argued against Plato’s view of a single good noting that existence of the universal good would mean that there should be “a single science dealing with all things.” Aristotle’s critique seems valid by an analogy: for if intelligence is good in the soul, as sight is good in the body, then the universal science of the good should be similar in relation to the good in both soul and body. If such a science does not exist then it must be true that such a relationship is not universal. Therefore, if Plato’s conception of the universal good is correct, then such science should necessarily exist by pure logic. In that case it is natural to ask if this science actually exists. Aristotle argues that it does not, since “in actual fact there are many sciences dealing even with the goods that fall into a single category.” This was problematic for Plato’s notion of the good because every science should have only one function, like every sailor, doctor or any human being has his own proper function. Therefore, if the good has many functions it is either divisible or these functions are not distinct. But if every good is derived from the single universal good, as claimed by Plato, then they all would share similar qualities and, therefore, would share the same function and would not be distinct. In that sense, it is mathematically precise and logical for Aristotle to conclude that good is divisible and many sciences exist in relation to different goods.
Aristotle’s final argument took on the endurance of good, since Plato argued that the “good-as-such” is more of the good because it is everlasting. Aristotle tried to object this difference by an analogy to whiteness: “whiteness which lasts for a long time is no whiter than whiteness which lasts only for a day”; therefore, goodness is no more of a good if it lasts longer. However, I think, this analogy is correct only if we assume that whiteness and universal good share the same kind of goodness. But if Aristotle truly believed that there is no universal good, then such an analogy would not be very meaningful because humans would be subject to different kind of good than colors, animals and other things. More precisely, good for humans would be necessarily some sort of mediation between pain and pleasure, since happiness, which is a part of Aristotle’s definition of a human good, could not be achieved without experiencing both of them. Hence, proper analogy should be considered in terms of how much pain good inflicts and how much pleasure it delivers. Having made the distinction the question of permanence becomes easier: if bad lasts longer, then it inflicts more pain, therefore, less of it is preferred to more. Similarly, if good lasts longer, then it delivers more pleasure and more of it is preferred to less. Thus, it logically follows that good which is everlasting will be more of a good, because it will deliver more pleasure and would be preferred by everyone. Hence, it seems that Aristotle’s notions of pleasure and pain, in fact, help to support Plato’s view that the duration of good is important determinant of the quality of goodness.
To sum up Aristotle provided a strong critique of Plato’s view of the good. His arguments are largely based on mathematical and logical reasoning, which Plato acknowledged as means of understanding true forms of things. However, it is also important to use this reasoning properly so that substances and qualities would correspond to proper analogies. On the other hand, in the case of everlasting good it might have been beneficial for Aristotle to acknowledge that longer lasting good is more of a good, since life of a human being is a continuous process and, on moral grounds, humans should be rewarded with becoming “more good” if they act morally and justly throughout their lives, equally as wrongdoers should be punished for their misdeed and faults.