I suspect most people have not read the full essay, so they never saw this paragraph:
The long and the short of what I'm trying to get across is quite simply that, in the absence of technology indistinguishable from magic — magic tech that, furthermore, does things that from today's perspective appear to play fast and loose with the laws of physics — interstellar travel for human beings is near-as-dammit a non-starter. And while I won't rule out the possibility of such seemingly-magical technology appearing at some time in the future, the conclusion I draw as a science fiction writer is that if interstellar colonization ever happens, it will not follow the pattern of historical colonization drives that are followed by mass emigration and trade between the colonies and the old home soil.
Many people here are arguing for "magic tech that ... does things that from today's perspective appear to play fast and loose with the laws of physics." I suspect that many of the people doing this either don't realize they are, and/or don't really understand physical laws as we currently understand them.
Yeah, but give it another 200 years and those magic wands may be possible.
I'm not holding my breath as neither me nor my children or grandchildren are leaving this planet, but look at the progress in technology we've made since the industrial revolution happened.
Indeed. Two hundred years ago it seemed impossible to cross the Atlantik in less than a week, now we can send people to the Moon and back in that time.
His point is that exactly every single notable achievement in the history of mankind has been preceeded by people saying things just like these - skeptics who keep saying "it can't be done" up until the very last second before "it" is done.
It was said about crossing the seas. It was said about colonizing the surface of the planet. It was said about diving deep into the seas and it was said about taking off ground. It was said about leaving the atmosphere. It was said about reaching out into space. It is currently being said by some about colonizing our solar system, and most people currently feel that the thought of us not colonizing our solar system is ridiculous, and in time the thought of us not leaving this solar system to go on to the next one will be considered just as ridiculous. "Scientists" like these often suffer from the common problem of never being able to see farther than their own nose; they constantly forget that we grow, and grow, and grow. Without meaning to sound pretentious and cheesy, here's a nice quote from a certain sci-fi series that came to mind: "It's our destiny to walk among the stars", and you can be damned sure that we will, providing we won't kill ourselves on the way.
E.g. nuclear pulse fission/fusion is literally 1960s tech. See the Orion project (or NERVA).
There are other proposals, which haven't gotten much funding.
The whole field of propulsion research has been underfunded since the 1970s, probably because NASA didn't want to risk creating competition for their big job program -- the Shuttle...
