Humans are tough. Slow to start. But when we get going; we keep going. In an endurance race, we can outrun horses. And most other land animals. We can do this regularly, often ably winning one day after another for a very long time. It seems that the human body has wonderfully adapted to the Earth in a way that makes us so successful.
And humans are great thinkers. We’ve invented and promoted machines. Using controlled sources of energy, we control machines to our great advantage. They carry us in the air, drill us holes through mountains and provide us views of the surface of other planets. But they, like humans, need energy.
Will robots replace humans? Or do we still have the advantage? A small, wheeled robot used to explore a room might start with an energy content of 10Wh/kg. A purpose built electric car begins with an energy content of about 2500Wh/kg. An adult human with an energy usage of 10.5MJ/day and the ability to live for 30 days without eating has an energy content of about 1500Wh/kg. From this, it seems that humans are closing in upon a mechanical replacement.
However, the biggest difference is that humans can obtain energy from a vast assortment of readily available foodstuffs. As long as the food remains available, humans can function. Robots on the other hand require very clean potential power. Usually in the form of electric current from batteries. If humans maintain control over this power then we won’t be replaced by robots. In the future, if there’s a shortage of mechanical energy, will humans still be tough enough for whatever opponent they encounter?