Soul Function

The basic premise of my book, How To Be An Excellent Human, is that human happiness is found in functioning well:

Functioning well means doing what we are good at and doing it in a good way, a way that promotes and enhances our ability to do it. When we function well, we experience happiness [and] fulfillment.(1)

This essay is an attempt to explain what I mean by that passage and to answer some objections. The idea that functioning well is important for human well-being goes all the way back to Plato and Aristotle. My account of the matter takes inspiration from their insights but differs in some details. I suppose you could call me a neo-Aristotelian.

In Book I of The Republic, Plato gives a brief account of how human happiness has to do with performing a specific function well.(2) A much fuller account is found in Aristotle, in the Nichomachean Ethics:

[A clearer account of happiness] might perhaps be given, if we could first ascertain the function of man. For just as for a flute-player, a sculptor, or an artist, and, in general, for all things that have a function or activity, the good and the ‘well’ is thought to reside in the function, so would it seem to be for man, if he has a function.(3)

Aristotle’s aim is to find the function of the human being. We’ll take up that idea shortly, but first we need to get clear on a few concepts. The first is happiness, which the Greeks called eudaimonia, often translated as “flourishing.” The second is soul, the Greek word for which is psyché (pronounced “psoo-khay”). We get words such as “psyche,” “psychology” and the like from this Greek root. The third is function or work, the word for which in Greek is ergon. We get the word “ergonomics” from this root. And the fourth is excellence, areté in Greek.


Eudaimonia literally means being accompanied by a good (eu) spirit (daimon). If one is accompanied by a eudaimon, a sort of guardian angel, then one’s life goes well; hence, the translation “happiness.” Nowadays we find the notion of guardian angels fanciful, but there is a spirit that does accompany each one of us at all times: our own spirit, our own soul. By extension of the Greek idea we can say that eudaimonia means wellness of soul.(4)


But what is soul? The word psyche is often translated as “soul,” but it does not mean a single enduring entity, such as Descartes’ res cogitans (thinking thing). It is not the entity said to live on after death in many religious theologies. The Greek word is derived from a root meaning to breathe and, by extension, to live. We can think of it as the animating spirit or vital breath of a living being.(5) Living beings, we can say, are ensouled. Instead of saying that a person has a soul, it would be more correct to say that he or she simply has soul, or perhaps soulness.

Soulness has two aspects, objective and subjective. Greek thinkers before Aristotle recognized two characteristics that distinguish what has soul in it from what does not: movement and sensation.(6) Objectively, from the outside, we observe that living things are animated; they grow and maintain their form through metabolism. and have their source of motion in themselves. Soul in this sense is the animating principle by virtue of which a living being is alive. Aristotle says that “what has soul in it … displays life.”(7)

Subjectively, from the inside, we observe our own life, and we find that the world appears to us, and that we engage with it. The world, we surmise, does not appear at all to nonliving things, but it does appear to living beings. We recognize that some elements of what we experience—trees, chairs, people and the like—are experienced by others as well; and others—thoughts, feelings, emotions and the like—are experienced directly by each of us alone. Soulness in this sense is a coherent world appearing to a particular point of view. Soulness is coherence of interiority. If that interior coherence is rich, full and harmonious, we call it happy and say that in such a state we flourish.

And what causes our interior state to be harmonious, fulfilled and happy? Both Plato and Aristotle say that such a happy state comes from doing our function well.


The term “function” (ergon, also translated as “work”) has been the subject of much analysis. It basically means what something does or what it is there for(8), what good it does.(9) It may also mean how it works.(10) Plato says that a thing’s function is what only it does or what it does better than anything else.(11)

There are two kinds of function, and unfortunately both Plato and Aristotle confuse them. The first is biological. For example, the function of the heart is to pump blood; the function of the eye is to see; legs and feet function to enable an organism to stand and move around. In all these cases the function of the part is to contribute to the ongoing life of the living being. Aristotle assumes that if there is a structure in an animal, it is there to do something. The part contributes to the well-being of the whole.

The second kind of function is instrumental, and instrumental functions most often involve a deliberate purpose. For instance, the function of a hammer is to drive nails. It does not drive nails on its own, but rather requires a human to pick it up and use it to do so. The human drives nails for some purpose, such as to build a house. The purpose of building a house is to provide shelter. And the purpose of shelter is to contribute to the ongoing life of the human being.

In both cases we end up with a contribution to life, but in the biological case the contribution is direct and need not involve any deliberate purpose, whereas in the instrumental case the contribution is indirect and does involve deliberate purpose.

As I said, Plato and Aristotle confuse the two meanings, sometimes referring to biological function and sometimes referring to instrumental function. In The Republic Plato gives the example of a pruning knife, the function of which is to trim branches. Other kinds of knives would work, but pruning is best done with a pruning knife, so that is what the pruning knife’s function is.(12) This is clearly an example of instrumental function. Aristotle at times uses similar examples. He says that a good horse is one that is good at running, at carrying its rider and at standing steady in the face of the enemy.(13) In this context a horse is a military instrument to be used by its rider. But in other places Aristotle speaks of biological function:

As eye, hand, foot, and in general each of the [bodily] parts evidently has a function, may one lay it down that man similarly has a function …?(14)

It is in the biological context that we can understand the function of the human.


The final concept we need to understand is areté, often translated as “virtue” but more properly rendered as “excellence.” (“Virtue” is used in its somewhat archaic sense of power or potency, as in “a potion with the virtue of removing warts.”) A thing is excellent if it does what it does in a very good way, that is, if it is effective at performing its function.(15) For instance, the function of a rabbit’s legs is to enable it to run. The better they are at this function, the better for the rabbit. Excellence promotes the animal’s well-being.

The Function Argument

Aristotle’s assertion is that an excellent human, one who performs the human function well, is a happy (eudaimon) human. But what is this human function?

In Aristotle’s view the human function is what human soul does, and not just what human soul does but what it alone can do or what it can do better than anything else. Aristotle contrasts human soul with two others, that of plants and that of (non-human) animals. Plants, animals and humans are all alive. All have soul. Soulness in plants enables them to take in nutrients, grow and reproduce. Soulness in animals enables them to do those things and, in addition, to perceive their world and, in most cases, move around. The soulness of humans is that humans do all that plants and animals do and even more. Humans have, in addition, the power to think rationally.(16)

The connection between functioning well and well-being is not magical and not arbitrary. A plant that absorbs nutrients well does better than one that absorbs nutrients poorly; that is, it has a better chance of surviving, thriving and reproducing. An animal that perceives its world and gets around in it well has a better chance of surviving, thriving and reproducing than one that does these things poorly. Similarly, human beings who think well have a better chance of surviving and thriving (for humans, reproducing is optional) than those who think poorly.

We humans partake of all three kinds of soulness, all three ways of sensing and engaging with the world, but the specific excellence of human soul, Aristotle says, is found in thinking rationally:

The function of man is an activity of soul which follows or implies a rational principle. … human good turns out to be [this] activity of soul in accordance with virtue [areté, excellence].(17)

By “in accordance with virtue” he means doing so well. In other words, when you think well, then you function well and flourish.

Aristotle says a lot more than this, of course. He discusses virtues such as courage and temperance, the need for sticking to a middle ground between excess and deficiency, the obvious influence on happiness of having friends and enough material goods to sustain yourself, and so forth. But he ends up saying that the life of pure study, such as is enjoyed by philosophers, is the best.(18)

Beyond Aristotle

Coming from a philosopher, perhaps this conclusion is not surprising. But is it correct? I think not. Leaving aside the difficulty of comparing lives, Aristotle seems to confuse what is best for a particular person and what is best for human beings generally.

Aristotle does recognize that there is more than one kind of thinking. Two of them are practical reason (phronesis), which is directed at accomplishing things in the world, and theoretical reason (theoria), which is aimed at disinterested understanding. The ability to think well in practical terms is obviously useful. But not everyone is suited for a life of theoretical contemplation.

Some of us are good at that sort of philosophical thinking. Some of us are good at other things: sports, music, crossword puzzles, mathematics, caretaking, fixing things, gardening and many more. But few of us are good at all of those things. On an individual level, each of us is well advised to find out what he or she is good at personally, or idiosyncratically, and to pursue and develop those talents. By and large, we will be happier doing what we are good at than doing something else. (Perhaps not universally. I know someone who is good at plumbing, but does not much enjoy it. In his case I suspect he is even better at other things.)

Aristotle wants to know the good for humans generally, for all humans considered just as humans. His conclusions are based on observation of the similarities and differences among living things. He was a sharp observer of the natural world, but modern scientific knowledge has far surpassed his elementary classifications. The distinctions between animals, plants and humans are not nearly so clear-cut as he thought. We know that some plants can sense quite keenly what is going on around them and even seem to have a form of intelligence.(19) Many can move, in most cases slowly compared to animals, although some, such as the Venus Flytrap, quite rapidly. And we now know that some animals—birds, octopuses, and chimpanzees, for instance—are far more intelligent than we had previously thought.(20) The ability to think is not limited to humans. Perhaps humans do it better than every other kind of being, but we are certainly not the only ones who do it.

But we humans do have an ability that goes well beyond what any other animal can do: we can turn our attention to ourselves. Even more than intelligence, the capacity for self-reflection—that we are able to turn our attention to our own experience, to take ourselves as an object of thought and perception—is what makes us uniquely human. Variously called self-knowledge, self-awareness, higher-order thought, and metacognition, the ability to take ourselves as objects of concern enables us, within limits, to develop ourselves and improve our functioning. I like to call this capacity second-order thinking, the first order being thinking directed at the world. The second order is thinking directed at oneself, and it, not thinking alone, is the uniquely human function. It enables us to improve and enhance all our other functions.(21)

Here is an example. One of the objections to the function argument is that it can be oppressive. One of the obvious functions of women is to have babies. Hence, the oppressive argument goes, they should be confined to that role. The Nazis advised women to stick to Kinder, Kirche und Küche (children, church and kitchen). Patriarchal prejudice punishes women who try to succeed in business, politics or any other role traditionally assigned to men. Not only is this attitude damaging to women, preventing them from reaching their full potential, it is a mistake. The mistake is to think that human nature is exhausted by its biological functions, that humans are only their biology. And it is our ability to think about ourselves that enables us to recognize the mistake.

Every human being is indeed a biological organism. Every biological organism has three goals built in, so to speak, to its very being: to survive, to thrive and to reproduce. So you might think that those are the built-in goals of every human. But they aren’t. Some of us do not choose to reproduce; some do not choose to thrive; and a few do not even choose to survive; instead, they commit suicide.

Of those who choose not to reproduce there are those who feel no sexual attraction to the opposite sex; and there are those who do, but for various reasons choose not to have children. Of those who choose not to thrive, there are those who are addicted to harmful behavior such as smoking cigarettes, and there are those who devote their efforts to a cause at some cost to their own well-being. I do not know how many types there are of those who commit suicide. For many of them, I suppose, life has become unbearably painful; and the urge to avoid pain, which is an element of the urge to thrive, overcomes the urge to survive.

Our animal nature is strong. Even those who choose not to reproduce cannot choose to be unaffected by the drive to reproduce; we all feel sexual urges. Even those who choose not to thrive cannot choose to have no desire for what is pleasant and nurturing. And those who commit suicide have to make a lot of effort to overcome the powerful urge for self-preservation.

What is it about humans that enables us to overcome these built-in biological drives and to pursue other ends instead? It is second-order thinking, our ability to think about ourselves.

Much more could be said about this human function, including how best to deploy it, and I do say more in my book. We humans have lots of other functions, skills and talents. We have a place in the broad scheme of things. There are ways our functioning is impaired, and there are ways to correct that impairment. The more we know about all these things—that is, the more we examine our lives, as Socrates recommended—the better our chances are for a flourishing life.


(1) Meacham, p. 6

(2) Plato, The Republic, 351e – 353d.

(3) Aristotle, Nichomachean Ethics, I.7, 1097b 22-29.

(4) Wikipedia, “Eudaimonia” and “Eudaimonism.”

(5) Bible Hub, “5590. psuché.”

(6) Aristotle, On The Soul, 2, 403b 25.

(7) Aristotle, On The Soul, 2, 413a 20.

(8) Wright, “Functions,” p. 146.

(9) Foot, Natural Goodness, p. 32.

(10) Korsgaard, “Aristotle’s Function Argument,” p. 138.

(11) Plato, The Republic, 353a.

(12) Plato, The Republic, 353a.

(13) Aristotle, Nichomachean Ethics, II.6, 1106a 20

(14) Aristotle, Nichomachean Ethics, I.7, 1097b 30.

(15) Wikipedia, “Areté (moral virtue).”

(16) Aristotle, On The Soul, 2-3, 413a 20 – 415a 10.

(17) Aristotle, Nichomachean Ethics, I.7, 1097a 5 – 15.

(18) Aristotle, Nichomachean Ethics, X.7-8, 1177a 10 – 1179a 30.

(19) Wikipedia, “Plant perception (physiology).”

(20) See for example Ackerman, The Genius of Birds, Montgomery, The Soul of an Octopus, and the many works of Franz de Waal.

(21) There are actually a number of functions that humans do better than other species. Long-distance running is one. Hairless bodies that sweated heat away enabled our ancestors to run down game animals that were faster than we were but could not keep going as long without overheating. Cooking is another. Cooked food is more digestible than raw; eating it freed up calories to grow our brain. Tools and language are other ones. Other animals use tools and have rudimentary language, but ours are far more developed. See Lieberman, The Story of the Human Body, and Wrangham, Catching Fire. Second-order thinking surpasses these functions by enabling us to augment and improve them.


Ackerman, Jennifer. The Genius of Birds. New York: Penguin Press, 2016.

Aristotle. Nichomachean Ethics. Tr. W.D. Ross. Introduction to Aristotle, Ed. Richard McKeon. New York: Random House Modern Library, 1947. Available online at

Aristotle. On the Soul. Tr. J.A. Smith. Introduction to Aristotle, Ed. Richard McKeon. New York: Random House Modern Library, 1947. Available online at

Bible Hub. “5590. psuché.” Online publication as of 28 February 2017.

Foot, Phillippa. Natural Goodness. Oxford: Oxford University Press, 2001.

Korsgaard, Christine M. “Aristotle’s Function Argument.” Online publication as of 3 December 2008.

Lieberman, Daniel E. The Story of the Human Body. New York: Random House Vintage Books, 2013.

Meacham, Bill. How To Be An Excellent Human. Austin: Earth Harmony, 2013. Available at

Montgomery, Sy. The Soul of an Octopus. New York: Atria, 2015.

Plato. The Republic. Tr. Paul Shorey. The Collected Dialogues of Plato. Ed. Edith Hamilton and Huntington Cairns. New York: Pantheon Books, 1963.

Wikipedia. “Areté (moral virtue).” Online publication as of 1 March 2017.

Wikipedia. “Eudaimonia.” Online publication as of 16 December 2008.

Wikipedia. “Eudaimonism.” Online publication as of 16 December 2008.

Wikipedia. “Plant perception (physiology).” Online publication as of 1 March 2017.

Wrangham, Richard. Catching Fire: How Cooking Made Us Human. New York: Basic Books, 2009.

Wright, Larry. “Functions.” The Philosophical Review, Vol. 82, No. 2 (Apr., 1973), pp. 139-168. Online publication as of 22 May 2012.

How To Be An Excellent Human

Mysticism, Evolutionary Psychology and the Good Life by Bill Beacham, Ph.D.

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