Quite. But reduce the destructibility of man “by nature”, (through bio-technology, and all that stuff) and he *approaches* the robot’s state, no?
No; we are mortal, by which I mean this.
We, as conscious beings, are a certain configuration of matter and energy (which means a configuration of moving matter). If our pattern is disrupted in any number of tiny ways, for even a moment, we cease to exist.
Now, the most common way in which our patterns are destroyed is from the sum of the countless, imperceptible ways they’re damaged during the course of any given day (meaning old age), and that’s not likely to change anytime soon. However, even if we did find a solution to that, there are so many other ways to die that they cannot be enumerated - and some of them just can’t BE fixed. If your body gets hot enough the individual proteins inside of your cells get bent out of shape (we usually call it “cooking”), and that’s caused by what proteins fundamentally are; to make yourself un-cookable you’d have to replace your own body with something inorganic, which would probably kill you.
Think of Wolverine, from the X-Men; let’s suppose that we could make our bodies heal themselves the way his does. OK. Well the way our cells reproduce is governed by these little caps of DNA, on the end of their chromosomes, called “telomeres”; we may actually be able to do that by changing our own telomeres. And we have tons of evidence that cells with abnormal telomeres do, in fact, grow and heal themselves like crazy - we usually call them “tumors”. If Wolverine were real, he would probably die at 30 from cancer.
I could go on, but I think you get the inductive point I’m trying to make. When I say that “we are mortal” I mean that we are fundamentally and inherently different from the indestructible robot. We will always be destructible.
And that doesn’t mean that we shouldn’t try to live longer, cure cancer and solve senescence; just that we shouldn’t think of actual immortality as a real possibility.