What it means to be human

Here’s a set of ideas that changed my thinking about my own identity — about what determines who I am.

The ideas start with a thought experiment.

Feral humans

Imagine a catastrophic event which wipes out everyone over one year old. Many infants survive, and somehow are able to grow to become adults. The result is an entire species with zero knowledge preserved from before the catastrophe.

All knowledge and culture is lost. Would books be any good? Would laptops or the internet?

I can only imagine the remaining people behaving as if our current civilization never existed. I don’t think the things we leave behind — empty houses, unread libraries, abandoned cars—would make much difference to the new society.

Do you think these future humans would have a strong sense of their place in the world? Do you think they would quickly develop language, compassion, and sophisticated social protocols?

Data points

There is some real evidence, outside of thought experiments, that feral humans would fare poorly—that a cultural reboot is not something we would easily recover from.

There have been many reported cases of feral children being discovered and brought back into modern society. It’s tricky to draw specific conclusions from these cases as many have been shown to be hoaxes or otherwise unreliable. However, there appear to be a few common attributes of these people:

  • they have great difficulty learning a language once returned to society,
  • they react minimally to stimuli such as loud noises or differences between hot and cold, and
  • they mimic the behavior of animals they’ve spent time with, such as walking on all fours.

These clues suggest a vast gulf between our current civilization and what we would be without passing on our knowledge.

There is at least one reliable source whose experiences we can learn from: Helen Keller. She became deaf and blind at the age of 19 months. Historians speculate that her senses were lost due to scarlet fever or meningitis. For many years she grew up virtually unable to communication with the outside world.

When Keller was 7, a teacher named Anne Sullivan began showing her how to spell words traced on her hand. Keller proved an excellent student. She was never a feral child, but she provides a rare coherent insight into what a well-educated person might say about life before contact with modern society.

The truly remarkable passage below is from her book, The World I Live In, in a chapter called Before the Soul Dawn:

Before my teacher came to me, I did not know that I am. I lived in a world that was a no-world. I cannot hope to describe adequately that unconscious, yet conscious time of nothingness. I did not know that I knew aught, or that I lived or acted or desired. I had neither will nor intellect. I was carried along to objects and acts by a certain blind natural impetus. I had a mind which caused me to feel anger, satisfaction, desire. These two facts led those about me to suppose that I willed and thought. I can remember all this, not because I knew that it was so, but because I have tactual memory. It enables me to remember that I never contracted my forehead in the act of thinking. I never viewed anything beforehand or chose it. I also recall tactually the fact that never in a start of the body or a heart-beat did I feel that I loved or cared for anything. My inner life, then, was a blank without past, present, or future, without hope or anticipation, without wonder or joy or faith.

I read Keller’s book hoping to understand what consciousness might be like to someone without language. My most optimistic hope was to get a glimpse of an untainted alphabet of human thought — an idea pursued by Gottfried Leibniz in what he called the characteristica universalis. My most pessimistic fear was to find a world of muddled, simplistic reasoning.

What Keller describes is a mode of existence more desolate than I could have imagined. No personal identity. No rational thought. No sense of time. Not even love? Is it possible that love is learned?

What makes a species?

What do these sparse data points and this thought experiment have to do with reality?

It seems to me that we can view imparted knowledge as cultural DNA.

Modern life has millions of cultural alleles — little choices that, together, mold our perspective. Is your family full of doctors? What kind of education did your friends get? Were you taught to say “bless you” when someone sneezes? What shows or books or apps do your friends like?

These ideas are fuzzier and easier to change than standard genes. You have some choice about how you internalize them. Your personal take on a single allele may change over time. The cultural DNA you pass on is a more consciously curated set of ideas than your biological DNA.

Despite the difference in transmission and storage between cultural and biological DNA, we could use common ideas to study both. In particular, the mechanisms of evolution may apply to cultural alleles. Ideas survive and prosper based on their suitability for the environment they live in.

On the other side of the same connection, our current picture of human evolution feels incomplete without taking cultural DNA into account. Our biological hardware changes once a lifetime, yet our mind’s software never sits still. Since so much of who we are comes from what we think, it’s a mistake to focus purely on the hardware. Humanity is evolving — right now — and I don’t think we’re really paying attention.

Isn’t this just nature vs nurture?

In jotting my notes for this post, I struggled to articulate why this perspective shift felt profound to me. To solidify my own thinking, I had to realize the assumption I had that was being challenged: the idea that who I am depends primarily on my physical presence alone. Put another way, I used to think that if I were born in another country, or 50 years earlier or later, I would have been, on some level, the same person I am here and now.

I now believe this is egregiously false.

It’s a bit disturbing that the world around us determines so much of who we are. It’s tempting to dismiss the power of outside influence as insignificant. It would be nice if we could quantify the difference in importance between our biological and cultural DNA.

Although imperfect, here’s a quick question to find some objective numbers: how much information can we learn compared to what we are given in our biological DNA? We can look at both our brain capacity and our genetic capacity as stores of digital information — or at least explore numbers that attempt to capture the digital information equivalents. I’ll use bytes as the fundamental unit, since this lets us think directly in terms of file sizes or computer memory.

In a Scientific American post, psychology professor Paul Reber describes the human brain’s effective digital capacity at around 2.5 petabytes. That’s 2.5 million gigabytes. Yevgeniy Gregoryev provides a value of 1.5 gigabytes for the amount of information stored in the human genome. The difference is staggering:

A single human brain has the capacity to store over 1,000,000 genomes.

If my initial thought experiment and data points seem unworthy of a meaningful perspective shift, I hope this number might change your mind. We’re not a 50/50 nature/nurture creature. Who we are emerges from the world left by the generations before us; those after us are built of the ideas we pass on.

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