>Rather than looking at that 400 year old as a wrinkly shriveled codger,
imagine
>someone who looks 25 but is actually 400 years old.
One of the cleverest tricks Larry Niven ever came up with was his
realisation that old rejuvenated people would be readily detectable - by
their almost supernatural grace and effortless physical poise. They've had
hundreds of years training in not falling over things, after all.
Whether we'll be memetically fluent with 400 years of algorithmically
compressed opinions reinforcing the same neural attractors - I would guess
not. Many sf writers have posited a regular (once a century, say) purging
or rewriting of the memories and habits, leaving just enough to retain some
measure of continued consistent identity... assuming you wish to be
`essentially' the `same person', which most transhumanists appear to doubt.
Damien Broderick