Anders Sandberg characterises the essence of transhumanism as:
Questioning the necessity and optimality of the current human condition, as well as suggesting that methods to improve it might be both feasible and desirable. If we were living in a fantasy world transhumanists would no doubt argue in favor of using cutting edge magic to improve life.
Sandberg notes that, in contrast, Nick Bostrom sometimes emphasises “the desire to explore the posthuman realm, the states of being that are currently unavailable to us”.
In practice there [are] plenty of transhumanists who are not terribly interested in becoming radically posthuman - a few extra centuries in comfort with enhanced minds and bodies is all right with them. They want to personally explore the nicer reaches of the human modes of being and maybe some near posthuman modes. But the common theme is that they do not see the current limitations as desirable, and think (with varying levels of confidence and evidence) that there are or will be ways of overcoming them.
Elsewhere, Sandberg writes:
All things considered, the human condition has many things going for it. Unfortunately, there are some problems. The need to sleep. Hangovers. Pain. Forgetfulness. Bad judgement. Cruelty. Depression. Ageing. Mortality. To name a few.
One approach is to try to accept these limitations and pains. Learning to live with adversity can sometimes be good for a person—it might teach them perseverance or humility . . . Unfortunately, adversity can also numb, harden, or crush us—and surely we should not just accept cruelty or ignorance as a fact of life.
Another approach is to try to ﬁx our limitations and problems. This is the goal of human enhancement: if we are forgetful, maybe we can improve our brains to forget less, for example by taking drugs that increase neural plasticity. To counteract ageing we might use gene therapy to increase production of enzymes that decline with age, remove aged and ill cells, or add fresh stem cells.
Human enhancement is all around us. The morning coffee or tea contains stimulating caffeine that counteracts sleepiness. Vaccines are a form of collective, global immunity against illnesses we may have never encountered. Less invasively, most of us live our lives with smartphones connecting us to a sizeable fraction of humanity and its knowledge. We are never alone, never lost, never bored, able to record anything. Our medieval ancestors would ﬁnd our (long, healthy, rich) lives superhuman.