It’s important always to step back and look at facts rather than extrapolate from fiction. First of all, we don’t use 10% of our brains. We use 100%. Nature is not frivolous and there’s no evolutionary mechanism by means of which any species can evolve an energy-intensive resource that remains largely dormant. This is why we don’t see elephants with large wings folded permanently across their backs, or lions with 200 legs, of which they use only four. It’s a stupid urban myth that has no place in any discussion attempting to consider real-world issues.
Secondly, we are already mutants. That’s how evolution works. Random mutations in our genes occur all the time. Mostly they have no impact, sometimes they are deleterious, sometimes they are advantageous, sometimes both (think of Huntington's disease, for example). By and large the deleterious mutations drop out of the gene pool because they impede the individual’s ability to survive and mate; by and large advantageous mutations are retained. That’s why we all have color vision, for example — the benefits were so huge every step along the way from monochrome through monochrome-plus-red to where we are today.
Thirdly, our genetic makeup is extremely complex, with many genes interacting in subtle ways to result in specific phenotype outcomes. We simply don’t know enough about how we’re built to engineer any major enhancements. Over time this will change, but why wouldn’t we want to engineer resistance to disease and correct hereditary ailments?
Fourthly, if we envisage a world in which (as usual) the wealthy get first crack at a new technology, that simply means we’ll all enjoy it a few years down the road. That’s the way scale function works, and why we all have anti-lock brakes and airbags and crumple zones on our cars today instead of driving the Detroit Clunkers of 40 years ago. Frankly, given the intellectual paucity of our species I can’t see any downside in any technology that can improve our ability to reason. In fact, as our clever technologies are merely amplifying our human stupidity to catastrophic scale, it’s arguably the case that we need such enhancements as quickly as they can be engineered.
