A thought has been bothering me lately.

Humans are incredibly complex machines. We are the result of billions of years of evolution, and millions of years of increasingly sophisticated animal life. Our brains contain tens of billions of neurons. Our bodies can repair themselves, reproduce, move through unpredictable environments, regulate their own temperature, turn food into energy, fight infections, and somehow produce consciousness on top of all of that.

And yet, in an almost ridiculously short period of time, we have built machines that are already better than us at many things.

That feels strange.

Computers can remember vastly more information than I can. They calculate faster. They can search through quantities of information no human could read in a lifetime. And now artificial intelligence is beginning to challenge abilities that felt much more uniquely human: understanding language, recognizing images, writing software, reasoning through problems and creating things.

But I’ve started wondering: maybe humans were never particularly good at these things in the first place.

Evolution wasn’t trying to build the smartest possible human

It’s tempting to imagine evolution as an incredibly long engineering project. Give nature enough millions of years and eventually it produces this extraordinary general-purpose machine: us. But that’s not really how evolution works.

Evolution wasn’t sitting there trying to maximize intelligence, memory, strength or mathematical ability. It only needed organisms that were sufficiently capable of surviving and reproducing in their environment.

There probably wasn’t much evolutionary advantage to remembering ten million facts instead of ten thousand. Being able to multiply twelve-digit numbers in your head wouldn’t have helped much while looking for food.

Maybe our cognitive abilities are simply what worked for our particular way of surviving.

We didn’t need millions of years of engineering to beat the human brain at arithmetic because evolution never spent millions of years optimizing arithmetic. We built a machine specifically for it.

What if the same thing is true of our bodies?

Maybe we’re not that good at physical things either

Robotics still gives us plenty of reasons to feel special.

Watch a robot struggle with an unfamiliar object and then watch a four-year-old pick it up without thinking about it. Human dexterity is remarkable. So are our balance, locomotion and ability to operate in environments we’ve never seen before.

For a long time, those abilities have been extremely difficult to reproduce.

But I wonder whether we’re making the same mistake again. Maybe human movement isn’t close to some physical optimum. Maybe it’s simply what evolution needed to keep an animal alive.

We didn’t evolve to lift the maximum possible weight. A forklift easily beats us at that. We didn’t evolve to run at 100 miles per hour, fly, survive underwater for months or operate continuously without sleep.

Today we solve these problems with specialized machines. The remaining challenge is building one machine that can walk into an unfamiliar environment and perform thousands of different physical tasks with something approaching human adaptability. That’s still enormously difficult.

But AI has made me less comfortable saying, “Humans took millions of years to develop this, therefore machines will have an extraordinarily difficult time matching it.”

We have already seen how misleading that intuition can be.

So what is all our complexity doing?

If machines eventually become better at both cognitive and physical tasks, why is a human being so complicated?

Maybe part of the answer is that we’re comparing the wrong things. A robot can look surprisingly simple because much of what keeps it alive exists somewhere else.

Its electricity comes from a power plant. Its computation may happen in a data center. Replacement components come from factories. Raw materials come from mines. Software arrives over networks.

Humans carry an astonishing amount of infrastructure inside ourselves. We convert food into usable energy, regulate our chemistry, heal injuries and maintain our own cells. And, most remarkably, we reproduce.

At first, that seemed to me like a fundamental distinction. A human can create another human. A robot needs a factory.

But then I realized that isn’t entirely fair either.

Nature is our factory

Humans don’t actually reproduce independently. Take away our environment and we’re helpless.

We need oxygen, water, plants, animals, microorganisms, minerals and an enormous functioning ecosystem. Even the energy stored in the food we eat ultimately depends largely on processes happening outside our bodies.

In other words, we have a supply chain too. We just didn’t build it. Nature did.

A future robot might depend on mines, electrical grids, factories and semiconductor fabrication plants. We might say, “See? It can’t reproduce by itself.”

But a human depends on plants, animals, soil, water and an atmosphere. We don’t normally count those things because they were already here when we arrived.

Perhaps nature is our factory, and a factory is simply a machine’s nature.

Imagine machines eventually becoming capable of extracting raw materials, generating energy, maintaining factories, repairing one another and producing new machines without human involvement.

Would we call that reproduction? Or would we continue calling it manufacturing simply because it looks different from our own reproduction?

I’m not sure the distinction is as obvious as it first appears.

Why do we eat, anyway?

Our method of obtaining energy seems incredibly cumbersome. We grow living things, eat them, break them apart chemically and extract energy from them. This requires digestive systems, teeth, organs, waste removal and a huge supporting biological infrastructure.

Why not get energy directly from sunlight? Or electricity?

Evolution has to work with the energy sources available at the time. An organism evolving without sunlight or a usable supply of electricity has to get its energy another way. Evolution cannot simply redesign it from scratch when new possibilities become available.

It modifies what already exists. Once life develops one successful way of obtaining energy, future organisms inherit that machinery. Every modification has to remain viable at every intermediate step.

Evolution therefore doesn’t necessarily produce the design an engineer would choose if starting from a blank sheet of paper. It produces something that works and can be reached from what came before.

We’re incredibly complex, but we’re also incredibly fragile. Change our internal temperature enough and we die. Deprive us of oxygen for a short period and we’re in serious trouble. A relatively small failure in one critical organ can bring the entire system down.

Maybe complexity and robustness aren’t the same thing.

Maybe we’re so complicated partly because evolution kept modifying what was already there. Every step still had to work.

And then there are emotions

There is one part of humans that I find much harder to fit into this picture: emotions. Fear, love, anger, pleasure, loneliness, curiosity, attachment, grief.

Evolutionary explanations exist for why emotions can be useful. Fear encourages an organism to avoid danger. Attachment can help parents care for children.

But explaining why emotional behavior is useful isn’t quite the same as explaining subjective experience. Why does any of it feel like something?

Would machines need emotions in the first place? If a machine already has a goal, could reasoning about what helps or threatens that goal be enough?

Even in humans, this isn’t clear to me. Why do we need to feel afraid rather than simply recognize a danger, understand its consequences and decide to avoid it?

What happens when survival stops being our job?

Most of our abilities evolved because organisms had survival problems to solve. Find energy. Avoid danger. Find shelter. Compete. Cooperate. Reproduce. Protect offspring.

Human civilization has gradually outsourced many of those problems to technology. AI and robotics could push that process much further.

Imagine machines eventually producing our food, building our houses, treating diseases, transporting us, manufacturing products and performing most economically useful work better than we can.

What would happen to us?

If so much of our evolution was shaped by the need to survive and reproduce, how would humans evolve when machines take care of most of those needs?

Could we become simpler? Taken to an absurd extreme, could we end up back where life began, as single cells supported by an enormous machine-built environment?

Then I think about music, games, stories, love and curiosity. People already spend so much time on things that seem to be about the experience itself. We want to feel moved by a song, get lost in a story, enjoy a game or feel close to someone.

And that brings me back to emotions. Music, games and stories seem connected to how they make us feel. I can imagine machines taking over the work of survival, but I still don’t know where that leaves this part of being human.

I’d love to travel 300 years into the future just to see what life has become—if we make it there.