converting sunlight into poo

What is the purpose of life? Many have spent their lives befuddled by this question, believing it to be a large, abstract, and complex issue. In reality, it is none of these things. There is an answer, and the answer is quite simple.  Please allow me to explain.

The study of teleology (the study of the “purpose” of things) has been around for a very long time, going back to Plato and Aristotle and probably even earlier than that. Aristotle considered the question of why things are the way they are. In the popular philosopher’s lingo of times, he referred to this as the “cause” of things.  One might ask: “What is the reason that this apple is what it is?”  The answer would begin: “This apple is an apple because….” and so on.

Aristotle postulated that there are four ways that you can answer a question like this. That is, there are four types of cause (or “be-cause”):

The material cause of something is the physical stuff out of which it is made: the “raw materials” of a thing. The material cause of your chair is the wood and plastic that goes into its creation. The material cause of your heart is the muscle and other cells that make it up. The material cause of a painting is the paint and the canvas.

The formal cause of something is the shape or form that it takes that makes it what it is. The formal cause of your chair is the specific shape of the legs and the seat that allow you to rest on it in a sitting position. The formal cause of your heart is the shapes and action of the valves and chambers. The formal cause of a painting is the shapes and patterns of colors that create the image that you see.

The efficient cause is the immediate physical process that brought it into being. The efficient cause of the chair was the person or machine that built the chair. The efficient cause of your heart is the metabolic growth process during your development as an embryo. The efficient cause of the painting is the act of painting by the painter.

The final cause is the purpose, end, aim, or goal of something. The final cause of the chair is to allow someone to sit. The final cause of an apple is…. well, we’ll discuss that in a bit. The final cause of a painting is whatever the painter wanted to express, or whatever feeling or reaction the painter wanted to elicit. It is whatever the motivation for the painting was.

By making these distinctions, Aristotle was pointing out that there are multiple ways of answering questions like, “Why is this apple green?” You could name the chemical compounds in the apple that absorb red light and reflect green light.  You could describe the structure of the surface of the apple and the way that surface interacts with light. You could explain the development of the apple and how its greenness came about over time. Or you could talk about the advantage that the apple has by being green, and why it might have evolved that way.  All of these are very different answers to the “why” question, but all of them are in their own way completely correct.

What is interesting, however, is that while three of these causes are more-or-less objective–material cause, formal cause, and efficient cause–the last of these causes seems subjective. The idea of a “final cause” seems in some cases to even be nonsensical.  The “final cause” is what we usually think of when we ask about the purpose of something. When we are talking about a man-made thing, like a chair or a painting, all is well and good: we can talk about either the motivation of the one who created the thing or the use that people get out of it once it is made.  But does it even make sense to talk about the “final cause” of an apple?  Or an ocean?  Or the wind?

For hundreds of years, people gave an answer of “yes!” and argued that the final cause of natural objects came from God: whatever God’s purpose for a thing is, that is the thing’s final cause.  Just because we do not know God’s motivation for making something doesn’t mean he doesn’t have one. God has a purpose for all things.

This is the answer that people gave when asked about the “purpose” of illness, misfortune, a discouragingly narrow mountain pass, or indeed life itself: it does have a “final cause”, which is objective, because it is defined by God’s will and intentions. Even if we don’t know what it is, God knows, and that’s what matters.

Then along came the materialists and atheists, the evolutionists and the physical scientists. Of course, their immediate and instinctive reaction was to do away with the notion of “purpose” for natural objects altogether. Eschewing mysticism or the notion of “divine intent”, they simply proposed the radical negation: things like apples, bad weather, and life simply have no “purpose” at all. “Purpose” derives from the motivation of a creator; there is no creator for natural things; ergo, these things simply have no purpose. Case closed.

Although this “simple answer” is appealing in some ways, it also does not “ring true”…. even to many atheists.  In his 1970 book Chance and Necessity, atheist and molecular biologist Jacques Monod said that trying to censor the entire idea of “purpose” out of the natural world was simply perverse. He used the example of a pumping heart: clearly the pumps in the heart have a purpose, and that is to distribute blood through the body so that oxygen and nutrients can be transported to all of the cells. Although evolution is not a “willed” action and there is no creator to have imagined a “desired end result,” it is clear that the action of the pumps in the heart is neither random nor coincidental. It is prima facie obvious that the pumps of the heart have a purpose.

Therefore, we must find some way of talking about the purpose of the heart that does not invoke the mystical, the religious, or the mythic. In short: rather than “doing away with” the idea of natural items having a purpose, we must find a natural way of defining and explaining it.

Monod’s example of the functioning of the heart gives us a clue about where to look. Living things are different from non-living things in that they are autopoietic: their parts interact in a way that constantly polices their own structure, making repairs and maintaining certain relationships in balance. This process can be called “metabolism” the most general sense; that is, not just eating, digesting, and excreting, but rather the entire process of taking in energy in and using that energy to create and maintain the structure of the organism and provide energy for any changes in structure (otherwise known as “behavior”) that are required.

Through evolution, living things have found more and more complex and inventive ways of performing this function: taking in energy, using that energy to create and maintain their own structure, and getting rid of any by-products through excretion. This is true from the humble single-celled organism all the way up to the most complex living things that we know of, and is even an accurate description of entire ecosystems. Indeed, one could look at the entire interwoven web of life on the planet as a large machine that over time has evolved to perform a singular function very, very well: use energy from the sun to police and maintain its own structure, to make more of itself, and produce waste.

Of course, different individual living things have adapted in different ways to different features of the environment. In a sense, you could talk about different types of living things each having their own purpose. In the same way that you could talk about the purpose of a heart being different from the purpose of a liver, you could talk about the different “purposes” of different organisms in an ecosystem.

However, the question regarding life in general is extremely straight-forward, and by now should be crystal clear: there is only one common and uniform action that is performed by every single organism, and indeed by the entire living ecosystem of the planet earth as a whole.

That function is the conversion of sunlight into poo.

That’s right, when you look at life as a general phenomenon–that is to say, not your life or my life or a cat’s life, by life itself–there is one operation that it has been doing since life first began. Evolution has generated vast and varied and complex ways for life to perform this action. Over time, this action has become refined and elaborated upon across countless generations of billions of species. But the phenomenon of life on earth has relentlessly, since the beginning, performed the singular function of converting sunlight into waste (poo).

That is even the main selection pressure that drives the evolution of all life: how well does it convert energy into poo? How efficiently, and how quickly is it able to convert energy into poo?  The more completely and quickly and thoroughly an organism is able to convert sunlight into poo, the better it does in the evolutionary game.

So, if there is anything that could be said to be the “purpose of life” at all–that is to say, not the purpose of any individual life but the purpose of the general phenomenon of life itself–then it must be this.

The purpose of life is to convert sunlight into poo.

So, please go and spread the good word. Tell a friend. Any time you get into a conversation about deeper philosophy, make sure to bring up this simple and elegant point. The problem of the “purpose of life” has, in fact, been solved.  The purpose of life is simple and easy to understand. It is to change sunlight into poo.

Now, the question of the meaning of life…. that’s a different matter altogether.

Converting sunlight into poo