Reply #35: The fact that our dentition includes incisors is a bit of evidence, no?

[GliderGuider]

I mentioned in another post that humans do use exosomatic energy whenever it's available. That's due to a combination of our survival instinct (another genetic component) with our intellectual ability to recognize and manipulate energy sources. The difference is that we will use various energy forms preferentially according to their perceived cost, with no intrinsic preference for a particular source as long as it fills our current need. So as long as the cost of one or the other energy source can be made to seem unacceptably high people will readily avoid it as long as alternatives are available. Nuclear energy is a good example of this, and frankly I'm hoping to transfer a similar stigma onto biofuels.

Yes, biofuels powered an agrarian society (at least until most of Europe and Britain were deforested). They could do so again, but you do run into a problem of scale with the society we have at the moment. If the world's population was reduced to a half billion or so farmers I wouldn't have many worries about the sustainability of biofuels. With 6.6 billion of us living in a global industrial society, though, I think concerns about sustainability and knock-on effects are reasonable.

It's not biofuels per se I have a problem with, you see. It's our current production techniques for biofuels considered within the context of our enormous global civilization and impending petroleum depletion. Oil depletion is what worries me most, because as I said above, "we will use various energy forms preferentially based on perceived cost, with no intrinsic preference for a particular source as long as it fills our current need." If petroleum becomes expensive and scarce I expect we will use whatever energy sources are available, and damn the consequences. The only hope for preventing catastrophic outcomes from that usage (given that our population situation remains unchanged) is for enough people to become aware of the issues to put some kind of brake on the more egregious misuses.