Purpose

A question I get quite frequently whenever talking about an exotic organism is "But what's its purpose?" It's almost exclusively asked by people who aren't too familiar with the natural sciences -- or rather, by people who aren't expecting the natural world to be as starkly weird as it really is. Usually I think it means the person is curious and surprised but doesn't really know what questions to ask; I also get the impression that some people who don't have much love for the natural world are a bit offended at the chutzpah of some species to be so flagrantly useless.

The question hinges on what exactly the person means by 'purpose'. Again, oftentimes they don't know themselves. The answer comes down to this for all living things: it doesn't need one, other than to survive and reproduce, and this is one of the most important things to keep in mind when thinking as a naturalist. The best way to respond to the question is, I find, to guide the person to asking the questions they would as a naturalist.

In the sense of 'purpose' as a goal the species is working for, it's always survival, propagation of the genes. But here, it's important to get rid of the idea of this as a conscious plan: many organisms have nothing resembling a consciousness -- remember, this question is valid for all living things, plant or animal or fungus or whatever. In this specific sense, the purpose of a dolphin is no different than the purpose of a slime mold. Animals with a complex sensory awareness of their environment are a relatively small group, and those with the intelligence (to use the word in its broadest sense) to consider the future are a small subset of that. In fact, "intelligence" is only useful for a species to the degree that it enhances the ability to reproduce more often than it dies; thinking that a species works to survive because it's relatively smart is exactly backwards. And generally speaking, each organism has its own methods of surviving, and you can talk about these unusual adaptations, or how they resemble those of unrelated species.

The question could also mean what role the species has ecologically. This is a much more interesting question. How something gets its food, how it avoids being food, how it reproduces, what other species it depends on and how, what environmental conditions it takes advantage or or protects itself from... there is much more variety in this type of response. You can talk about adaptations, and the counter-adaptations of other interdependent species. This is the meaning of 'purpose' that leads to the most other questions, and is one of the first questions a naturalist asks when investigating an organism. When someone doesn't really know what they mean by the word, I try to respond in this sense.

It can also mean what use the organism has to humans, another very good question to ask. This could be economically or medically, or whether its edible or not, or dangerous, for example. However, for a naturalist, this is just one detail out of many. Many people will try to gauge the value of a species in this sense, but for a naturalist that's exactly like judging a species for, say, being camouflaged, or having compound eyes. Clearly it's an important question for one species (ours), but to think like a naturalist means to ignore the fact the you personally belong to that species. That's a conscious process: no naturalist actually believes they're above human concerns, but if Homo sapiens is your only reference point, you're going to miss out on many interesting things that are simply outside our experience. Not to mention there are certainly many species that we just haven't realized have some value to humans: it's impossible to say before we understand what value an organism has to others, or to itself. And again, even if an organism has zero use for humans, this is definitely not the same as saying it has no value -- and this response leads us to questions of the intrinsic value of the natural world, or what value it has that we as humans do not assign to it. Generally I don't emphasize this sense of 'purpose' unless the species in question has some surprising human value; the genes that cause some jellies to fluoresce are used in heart research, for example, which I think is a great example of how what looks like a "useless" species can literally save human lives in an interesting way.

Sometimes people are really asking about the divine purpose of an organism. I try to respond to this in one of two ways: either this question comes down to the human value, or the ecological role. But the question of what value an organism has to God is completely outside what a naturalist investigates -- by definition, the divine (and even the question of whether there is such a thing) is separate from the natural. It's more than unanswerable: an unanswerable question would be one that we could thoroughly investigate (or at least imagine a way to investigate) without discovering anything. Unanswerable questions are interesting because sometimes they become answerable. But any question involving how God or the spiritual realm relates to an organism is unaskable, not because it's somehow out of bounds but because there's no way to ask the question in a way that we can actually investigate in the natural world.

So the question of 'purpose' is deceptively simple. The most important thing is to show the person how to restructure the question into the ones they're really interested in, I think, because one important responsibility a naturalist has is to show others how to use the most useful tools they have: asking questions, carefully observing the natural world for answers, and realizing what new questions that brings up.