Genomics PhD Ruxandra Teslo asks:

[H]umans have only about 30,000-35,000 genes, two times less than a fly. Yet we are clearly more complex than a fly. How [is] that possible?

Creativity. That is, the ability to create new knowledge.

Put simply, organisms are computers that can move; their genes are the software. (That’s not a metaphor – it’s literally true.) In any non-creative organism, the onus is on genes to provide ~100% of the knowledge the organism requires to survive. But a creative organism, by definition, can come up with new knowledge during its lifetime.

Since a fly cannot create new knowledge ‘on the fly’ (pun intended), it needs ~all the knowledge it requires – flight, walking, etc – preinstalled in its genes. Likewise, a baby giraffe walks only a few hours after birth. Ducklings can walk and swim shortly after birth.¹

To put it in the context of my Neo-Darwinian approach to the mind: one of our ancestors had a genetic mutation causing ideas to start replicating imperfectly inside his mind. This caused more evolution of knowledge to occur during this ancestor’s lifetime and took some of the onus off his genes. If an organism can create some knowledge itself then biological evolution doesn’t have to create that same knowledge anymore. Many species come out the womb ready to walk, but humans learn to walk themselves. So humans don’t need genes that would otherwise enable them to walk automatically.

Consider also that unfavorable genetic mutations are more numerous than favorable ones. Since creativity can make up for many unfavorable mutations, there was unprecedented selection pressure favoring creativity at roughly the rate at which unfavorable mutations occur. Creativity is a big deal from an evolutionary perspective. (Well, from ~any perspective, but especially from an evolutionary one.)

On top of that, using their creativity, humans create additional knowledge that genes wouldn’t have given them to begin with. Genes don’t code for nuclear reactors and spaceships, say. When a human comes up with a new idea, his knowledge has increased, but his genome has stayed the same.

Specifically, it’s the property physicist David Deutsch calls reach that is responsible for this big difference between the human genome and the genomes of all other species. The human genome codes for creativity, and creativity has more than enough reach to cover the knowledge of any other gene the genome could have contained (and even of all those it presumably could not have contained).

A multiplication table takes up more space on a piece of paper than a simple multiplication algorithm. Yet the algorithm gives you more results: it has greater reach. Comparing the number of genes is like comparing the number of lines of code: just because a program is longer doesn’t mean it does more. You need to compare reach instead.

Humans are the only creative animal. The human genome installs the basics, most importantly the creative algorithm, and then humans figure out the rest (and then some) during their lifetime.

So it’s not strange that humans have fewer genes than a fly. It’d be weird if they had more.

Teslo also asks:

Another perplexing finding was that most of the human genome was composed of so-called “junk DNA” — that is, DNA that did not code for any protein. The central dogma of Biology says that DNA codes for RNA, which in turn codes proteins, the molecules that carry out most of our cell’s functions. So what was all the DNA that was not coding for any protein doing there?

Well, maybe the central dogma is wrong. But let’s assume for a moment it’s correct.

Creativity explains this, too. Let’s take the example of walking again. Some of our creative ancestors presumably knew how to walk from birth: some of their genes pre-installed this knowledge in them. Then an erroneous mutation broke those genes, and with them, the inborn ability to walk. In any non-creative species, such a mutation would almost certainly lead to death, but in a creative species, it doesn’t have to: again, a creative organism can simply learn to walk. So error correction shifted from biological evolution to the organism itself. What had now become “junk DNA” could remain junk, and even grow and devolve further, without posing any serious risk to the remaining intact genes’ ability to spread. This process has been going on for hundreds of thousands of years, so our DNA has had plenty of time to accumulate junk.

In other words, the junk in our DNA is evidence of the fact that, for humans, error correction has largely shifted from biological evolution to the evolution of ideas inside human minds. A key Popperian insight (after philosopher Karl Popper) is that, when you want to know which of two processes creates more knowledge, you compare their error-correction rates.

From a cursory search online, biologists disagree about just how much of our DNA is “junk”. I’m no biologist, but to the extent that it does exist, junk DNA is not a mystery – on the contrary, epistemology predicts it. It also predicts that humans should have a greater percentage of junk in their DNA than all other species.

In any case, the answer to both questions is essentially the same.

Teslo raises these two questions in the wider context of figuring out why medicine and biology aren’t progressing faster. As you can see above, epistemology can solve biological questions. Maybe we need more epistemology.