One of the most fascinating and ambitious of transhumanist ideas is the "Hedonistic Imperative", articulated by David Pearce, co-founder of the World Transhumanist Association (now Humanity Plus) with Nick Bostrom. To quote the site:
The Hedonistic Imperative, which I like to call "eliminating all pain, forever", seems to me to be the logical conclusion of the simple belief that pain is bad. Our lives are filled with so much unnecessary pain, much of which doesn't even serve any operative function. For instance, if someone initiates a confrontation with me, even someone who I will never see again and whose opinion I shouldn't logically care about, I feel bad about it for a while, longer than I should. There's a reason for this -- in the ancestral environment, all humans lived in small tribes of just 100-200 individuals (Dunbar's number). If I had a confrontation with someone, it could be a really big deal, because I'm practically guaranteed to see them or their associates again. But I live in a city with almost a million people, so why should I have to deal with this?
The Hedonistic Imperative outlines how genetic engineering and nanotechnology will abolish suffering in all sentient life.
The abolitionist project is hugely ambitious but technically feasible. It is also instrumentally rational and morally urgent. The metabolic pathways of pain and malaise evolved because they served the fitness of our genes in the ancestral environment. They will be replaced by a different sort of neural architecture - a motivational system based on heritable gradients of bliss. States of sublime well-being are destined to become the genetically pre-programmed norm of mental health. It is predicted that the world's last unpleasant experience will be a precisely dateable event.
The confrontation example is actually a very superficial one. Consider something more serious -- the mechanism of lethality behind the 1918 plague. Scientists think that the virus killed via cytokine storms, overreactions of the human immune system to the virus. The very bodily functions that were supposed to save us caused our doom. That's why the virus killed the healthiest human beings, not the very young or old, like typical flu. "Healthier" human beings had stronger immune systems, which went even more haywire when attacked by the virus, leading to their tissues being clogged up with excess fluids and macrophages, causing death.
Nature can be a cruel thing. There are endless examples. One of the most radical positions of many transhumanists is that the entire ecosystem should be reshaped to eliminate cruelty. Transhumanists have many "radical" positions, but this is one that even "moderate" transhumanists are prone to adopting, and for good reason. If human beings have no right to murder each other, then why should conscious animals have the same right? If a wolf kills a cat or a lamb that can feel pain, that represents negative utility. Yes, predators must eat prey to survive, but what if we could reengineer predators to eat "meat trees" or exclusively non-conscious animals?
Like many radical areas of transhumanism, these ideas are left insufficiently explored, for fear of being thought of as having our heads in the clouds. But why should academic philosophers have all the fun? Besides attracting thinkers to transhumanism with common sense ideas like "life shouldn't have to end at 120", why not give a try with more radical ideas, like "all of pain is reprehensible and it ought to be eliminated for all eternity"? There is little harm in pursuing simple moral ideas to their logical conclusions. From an information-theoretic standpoint, it's much simpler.
Though some people regard transhumanism as a complex philosophy, it is ultimately more mundane and simple than almost every other religious or secular worldview.
Michael's blog: Accelerating Future.