[darksaints]

An interesting theory as to why we never evolved with wheels is the idea that an evolutionary improvement requires a viable intermediate state...something that works well enough in the transition from inferior to superior. It is worth noting that human inventions can evolve in much faster timelines than biological evolution, but no matter how fast they come, there does need to be a way to fulfill intermediate needs, or else there is no path forward.

What follows is my own personal views on current technological evolution, which may be wrong. Regardless:

Electric vehicles have been evolving extremely rapidly, and now they are viable enough for most privately owned passenger vehicle use cases. Through continuous evolutionary investment, they may make their way to some commercial vehicles, maybe even small planes. But the chasm is so extremely large for large commercial vehicles like airliners and cargo ships, that we would need massive (several orders of magnitude) technological improvements in energy density in order to even start considering them.

SOFCs are inferior to batteries and supercapacitors from an efficiency standpoint. They may never be the power system of choice for passenger cars or other small scale and lightly used systems. But the thing they have going for them is their ability to evolve as the ecosystem evolves. They can run on diesel fuel, JP8, even crude. They can run on biodiesel, or renewable ethanol or methanol. And they can run on pure hydrogen. They can even run on a mix of all of those fuels. At every path in the transition to hydrogen, there is a viable intermediate state. For this reason, I think you'll see fuel cell powered cargo ships and airliners long before you see battery powered.

[thaumasiotes]

> An interesting theory as to why we never evolved with wheels is the idea that an evolutionary improvement requires a viable intermediate state

Not really; wheels aren't an improvement in the first place so there is no need to explain why they didn't develop. Note that it's easy to make robots that use wheels, and difficult to make robots that use legs, but we make legged robots anyway so that they'll be able to handle environments other than dedicated roads.

(More recently, we make flying robots, sidestepping the issue that we don't really know how to do legs well.)

[darksaints]

Okay, but evolution has given us some pretty expansive diversity in traits across the biological world. No single trait is pareto optimal, but relatively superior/inferior depending on context. Wheels have some pretty extreme efficiency advantages, useful for both speed as well as endurance. They come with disadvantages too, but there are plenty of animals who never need to leave environments where legs are optimal or even necessary for survival. There are some animals that will never leave grassy plains, for example. Yet none of them have evolved wheels either. We don't have marine animals that have evolved propellers, despite an edge in efficiency.

[XorNot]

Evolution is content with a very long iteration cycle and a very high failure rate.

Human engineering is much more efficient - building things we understand, we accomplish in decades what takes nature millions of years or is straight up not viable.

[codetrotter]

I sometimes think about evolution and its relation to human engineering, and I don’t know if it is a useful thought but, evolution created humans, and therefore, human creation is also in fact a product of evolution in nature itself.

In that way, evolution evolved itself by creating humans, and through us evolution is now happening at an accelerated rate in some aspects.

I try not to get all philosophical, because I know that other people, who are actual philosophers, have thought about these things already and I can’t compete with them but I can’t help but think about such things anyway.

[modo_mario]

Have you considered how these elements essentially detached from the body (it's why they'd be able to spin around) would grow and the like?

[drewbug]

"Many bacteria are equipped with a flagellum, a helical propeller that allows bacteria to travel."

[esotericn]

Humans didn't evolve with wheels because excepting the last few hundred (possibly thousand) years roads didn't exist.

How useful do you expect a set of wheels would be on the tundra? Or are you conceptualising a theoretical monster truck human? We'd be better off with tracks...