Doctor Who in its last three episodes for the 2007 season presents us with the ultimate fate of humanity. The Universe is collapsing into giant black holes and the last human survivors of the year 100 trillion (or so) have reverted to biological human form. They receive a call to a final refuge called “Utopia” and the Doctor helps them to escape one dying world at least. He notes in passing that the human race reverts to classical form time and time again, even after spending billennia as computer uploads and plasma clouds.
In “The Sound of Drums” and “Last of the Time Lords” we learn that the refugees on Utopia were ‘rescued’ by the Master, made into psychopathic cyborgs and brought back to 2007 to exterminate the current human species, to replace them and make an Empire ruled by the Master. So “We” morphed again.
But what might really happen?
Greg Benford does quite a good job of imagining how diverse genus Homo might become after a billion years in his “Beyond Infinity” – he has hundreds of human derived species being revived out of gene vaults after a long period of stasis self-imposed by Homo superior. I think self-directed evolution might mean that something like the human form can be retained into an arbitary futurity (like 100 trillion AD), but that by no means implies stasis at the molecular level. I personally can imagine lots of molecular level machinery gradually taking over from old-style DNA/RNA – which is a bit too labile for high radiation environments and odd chemistry. Life extension would demand something more stable since cancer and aging are both caused by breakdowns in DNA/RNA replication fidelity after too many cell generations.
“Smart matter” cellular machines might be required in the long run, addressable by a body’s operating system and able to undergo a degree of “morphing” into useful configurations – we would become our own tool-kits, assimilate silicates and metals, replace calcium minerals with carbon nanotubes, and augment biochemistry with higher energy density power-sources. Technology and biology will merge – if we are to survive in any kind of physicality in the billennia ahead.
That’s how I see our evolution panning out. Frank Tipler, in his “The Physics of Christianity”, believes we will all become Uploads, of necessity – even after the Second Coming of Jesus. Maybe. After all JC said “Flesh and blood can not inherit the Kingdom of Heaven” and “sons of the kingdom will be like the angels, neither marrying nor giving in marriage” – sounds much like a non-flesh based existence to me. But bodies will always be useful regardless of how portable the software we call “the soul” becomes. I think even our Uploaded descendants will still take classical human form as the need arises. There’s a lot of information processing potential in the dimers that make up cytoskeletal microtubules – our bodies are “stupid” because we don’t yet have an interface or an OS that can utilise that power.