(This is a summary of a chapter in a book I often used in university classes: Thirteen Theories of Human Nature. Brackets indicate my comments.)
Aristotle (384-322 BCE) was a student of Plato’s and the tutor of Alexander the Great. Aristotle’s background in biological subjects made him more of an empiricist [truth discovered primarily by the senses] as compared to the mathematician Plato’s rationalism [truth discovered primarily by reason.] Aristotle attended Plato’s academy but founded his own school, the Lyceum, later in his life. [Both schools would exist, in some cases off and on, for between 500 and almost 1000 years.]
Aristotle wrote on an amazing range of topics including logic, metaphysics, physics, epistemology, astronomy, meteorology, biology, psychology, ethics, politics, law, and poetics. [We can say that Aristotle influenced more subjects for a longer period of time than any thinker in history. His scientific ideas were orthodoxy for 2000 years, his logic is still used, and his influence in many areas of philosophy is still felt.] For our purposes, we will focus on the Nicomachean Ethics, based on lecture notes taken by his students.
Metaphysical Background: Forms as Properties, and the Four Kinds of Question – Aristotle is not a classical theist like Augustine or Aquinas, but he does have a conception of an unmoved mover, a changeless cause/sustainer of the processes of the universe. Again this is not a personal god who cares about human beings or is the object of worship. [It is more like a power or energy that keeps things in motion by attracting them toward it.]
Aristotle rejects Plato’s belief in independently existing forms. There is something common to things that share a concept x, but that essence/form/pattern/structure is embedded in the thing itself. [Everything is a composite of form and matter. The form is the pattern or structure of a thing and the matter is what makes something an individual thing. Everything in the world is a formed matter; that is matter in a certain form. You never find matter without form—which would be like a primordial goo—and you never find form without matter—with the exception of the unmoved mover. Some forms are very primitive—a brick is basically just the shape of heated clay—while others are very complicated—like that of a human being.]
But in what sense is the essence of catness shared by all cats? Is this form a thing or a quality? Does a given form like health or goodness apply to all healthy or good things? Aristotle thought not. You can be healthy or good in different ways so he doubted that there was a unitary form of goodness. Pleasure, honor, and wisdom may all be good, but they are good in different ways hence there is no single form of goodness.
Another way of understanding his metaphysics is to consider the 4 causes, four questions we can ask about a thing in order to understand it: 1) material cause—what something is made of? 2) formal cause—what kind of thing is it? 3) efficient cause—what caused it to exist? And 4) final cause—what is its purpose or function? [This works well to understand human artifacts like statues or books, but the idea of a final cause is harder to determine for people, much less for inanimate objects. Aristotle is expressing a teleological view of reality—the idea that nature is goal-oriented. [This view has been undermined and rejected by modern science.] But Aristotle’s analytic nature laid the groundwork for the analysis prevalent in modern philosophy.]
Theory of Human Nature: The Soul as a Set of Faculties, Including Rationality – Plato was a dualist who believed that we are composed of two substances, a material body, and an immaterial mind. Aristotle rejects this. As a biologist, Aristotle recognized that living things include plants as well as human and non-human animals. [He says that plants have a vegetative structure (a way of functioning) which is primarily about taking in nutrients, reproducing, and the like. Non-human animals have this structure plus a sensitive structure that uses senses to interact with the environment and initiates desires. Human animals add to this a rational structure which makes them unique.] Each different thing then has a different structure or form. This is its formal cause in his language. Thus some things have a richer or more complex form than other things.
Thus the form of something does not exist independently; it is not an entity in itself. Rather it is the specific pattern or structure or form of a thing which defines how it exists and functions. [It is different to be structured like a rock, tree, dog, or human.] Thus for Aristotle, it makes no sense to talk of a soul or mind without a body, for the essence of a person is embedded and intertwined with their matter. You can’t take it out of the body. [And to think Roman Catholic natural law theory is Aristotelian through and through.]
The only exception is that divine intellectual functioning may take place without a body. Yet it is hard to see how this could be the case. For example, even if computers think without bodies their thought still depends on material components. A disembodied thought is conceptually problematic, although many Christians and Islamists who followed Aristotle welcomed the possibility. As for ordinary embodied human beings, Aristotle’s major distinction is between their rational component and their emotions and desires. He also distinguished between theoretical and practical reasoning.
Aristotle also held that humans are social and political creatures who have activities common to all. He also thought that we can only reach our full development in societies. However he does not think that women are rational creatures, and his remarks are quite disparaging toward them. Perhaps worst of all, Aristotle advocated a doctrine of natural slavery—the idea that some are natural slaves. He thinks this is the status of non-Greek barbarians. Still, we should not reject the rest of Aristotle’s thought because he was a misogynist, racist, and imperialist. [Aristotle’s doctrine of natural slavery heavily influenced the Catholic Spanish conquerors of the new world, many of whom used it to justify their horrific treatment of the people of the new world. For more see the disputations during that time, particularly those held at the University of Salamanca.]
Ideal and Diagnosis – Rather than diagnosing a flaw in human nature and proposing a remedy, Aristotle gives us an account of the end, purpose, or meaning of life and how one might achieve it. Rather than offer an otherworldly account of salvation, he offers one for this world—one more akin to Confucianism or Buddhism.
Aristotle begins by asking if there is one thing at which all action aims; if there is one thing all action seeks for its own sake. Aristotle says that eudaimonia is that thing. Eudaimonia is variously translated as happiness, flourishing, well-being, living well, fulfillment, or perfection. In his own words “the human good turns out to be activity in the soul [mind] in accordance with excellence.” In other words, the good life is activity that involves rationality and embodying excellence over an entire lifetime.
Anything, even inanimate things, can function excellently. A good pen or a good dog functions as they are supposed to. Humans have both excellences of intellect—theoretical and practical reason—and excellences of character—virtues (excellences) like practical wisdom, knowing what to do in real-life situations by having learned from experience, as well as temperance, courage, and justice. In general, he presents these virtues as “the mean between the extremes.” A life of virtue (excellences of character) is the ideal for human life. [Like Plato he emphasizes moral and intellectual virtue.]
In contrast to the state of virtue [knowing, wanting, and doing the right thing] stand brutishness (vice) [which is to not know, want, or do the good]; badness (incontinence) [which is to not want or do the good, although one may know it] and lack of self-control (continence) [which it to not do the good, although one may want and know it. Unlike Socrates, who thought knowledge was sufficient for virtue (KSV) and Plato, who recognized inner conflict, Aristotle recognized how weakness of will implies that KSV is false. Knowing the good doesn’t mean one will do it.
Realization or Prescription: Political Expertise and Intellectual Contemplation – A key is that vice and virtue result from habits, which themselves are the result of past actions and environment, including the social and political environment. [Aristotle says that political science is the science which studies the good for humans.] This leads us to Aristotle’s conception of government and society. In brief, Aristotle believed that societies can only survive and flourish if there is some basic agreement about issues of private morality. [The founders of the USA thought that individual moral and religious pluralism was allowable, as long as the public, secular good took precedence.]
In thinking about the ideal life, Aristotle contrasts lives of pleasure, honor, and intellectual reflection. Not surprisingly he felt the latter was superior. He thought that intellectual contemplation was the highest and best human activity. [Plato argued that intellectual pleasures are better than physical ones. He says you can confirm this by asking anyone who has experienced both types, and they will prefer intellectual pleasures.] But in arguing that intellectual contemplation is the best activity, Aristotle doesn’t seem to fully account for how much one’s station in life affects their ability to live well.