Are Humans the Most “Evolved” Species?

Follow-up: Are Humans the Most “Complex” Species?

The most common trope in biology debates is anthropocentrism versus non-anthropocentrism: “Humans must be dethroned!” vs. “humans are special!” The traditional understanding of evolution is much like the diagram of a fish that crawls on land and becomes a reptile, then a mammal, then a chimp, and finally an upright, enlightened human. The diagram suggests that evolution has been working towards us. The new, countervailing voice says that such a view is human-biased, and that the diagram of nature is more like a wheel, with different intelligences radiating out [1]. After all, roaches and ants outnumber us in quantity and biomass, so what’s to say that we are “more evolved?”

Perhaps, like most dialectics, the answer lies somewhere in between. Anthropocentric bias has been so often on the wrong side of history that my intuition has been primed towards skepticism. However, the idea that we’re just as “good” as ants boggles another intuition. Obviously we’re more intelligent than ants, and obviously, we’re more complex, and yet it seems like a stretch to say we’re more evolved. Technically, every species is equally evolved because their DNA survived the same billions of years to arrive at the present. And smart people are leery of words like “evolved” because they sound too much like “good” and other value judgments, which is a good thing to be leery of if the goal is objectivity.

Perhaps word choice is the issue. Ray Kurzweil chooses the right words in The Age of Spiritual Machines. He prefers “order” to words like “complexity,” because complexity that doesn’t solve a problem is meaningless. Order is information that serves a purpose. By that definition, humans have the most order in the Animal Kingdom. Even so, saying as such is not much different than saying we’re the most intelligent. (One camp would even say we’re not the “most intelligent,” since crows have better memories than us, and other species have other intelligences greater than ours). There will always be a “most intelligent” species on any planet with life forms, but that still doesn’t mean it’s the most evolved.

But if there will always be a most intelligent species on the planet, and the diversity of species on a planet is always increasing, then the range of intelligence will always be wider than when life first started. The floor of order will always be roughly in the same spot, and the ceiling will always go up. Theoretically, the most intelligent species could go extinct, and then the second-most intelligent one would take its place, so it’s not strictly increasing. But, if humans went extinct, chimps would still be the high-water mark, and it’s likely they would radiate from there with a wider band of intelligence. Something more intelligent than chimps, or even humans, would eventually evolve. In the long-run, the global maximum for intelligence would rise.

In the Selfish Gene, Richard Dawkins talks about how human are expensive. We are born with fewer instincts than other animals, which is the result of our brain’s generalism. Being a generalist requires large, calorically-expensive brains, as well as lengthy parenting. Meanwhile, fawns start walking as soon as they leave the womb. That we are so expensive, and yet here we are, says something about our evolutionary durability. Does that mean we’re more evolved?

Maybe evolution is like a technology tree. Once DNA was invented, it never got antiquated. Once cellular organisms arrived, they never became obsolete. Similarly, once we developed object-oriented programming (OOP), it never went away. Even though OOP may be more high-level than machine code, the majority of code is still machine code. This comparison is analogous to humans being outnumbered by ants. The majority of written code is also from non-OOP languages, such as the C code that powers your phone’s operating system. But the majority of newly written code is in the OOP that undergirds the apps and services we use.

Any word that implies “better than” breaks down in objective debate. Science can never say we’re better than ants. But there is a high-water mark for technological sophistication in nature, and that high-water mark is always rising, and by that definition, humans are the most evolved.