> And as long as we can't get our energy without killing other living organisms It is perfectly possible to fuel a human only from biological sources that have

> And as long as we can't get our energy without killing other living organisms It is perfectly possible to fuel a human only from biological sources that have died a natural death. It's exactly the same as running a computer on fossil fuels, just without the millennia of waiting for sufficient accumulation that you need for building a whole industrial base in one short flash in the pan moment (compared to the millennia of accumulation). Actually, you don't even have to wait for organisms to die, you can even use fuels where the providing organisms live on, having just shed off a part they don't need anymore. No killing involved in eating an apple. And if you plant the seeds in an advantageous environment you are even taking an active role in their procreation, as the seeds that just drop into the shade of the parent tree won't thrive there.