Though not as well known to the general public, at least in the US, as someone like Stephen Hawking or Steven Weinberg, the Dutch physicist Gerard ‘t Hooft is a member of the uppermost echelon of theoreticians of the past few decades. I knew that he had endorsed the Mars One plan for a colony on the Red Planet but I had no idea he has long been an enthusiastic proponent of space settlement: Nobel physicist: Give people a one-way ticket to Mars – opinion/New Scientist.
Regarding the Mars One, he says
The concept fits in with my own ideas about human exploration of space, which I described in my book, Playing with Planets. In fact, the co-founder and general director of Mars One, Bas Lansdorp, once attended one of my lectures. When he asked me to become an ambassador for Mars One, my first reaction was that it will take much longer and cost much more than they currently envision. However, after learning more about the research they had carried out I became convinced that human flights to Mars could become a reality within 10 years. So in the end, I said yes.
Hawking is well known for his support for human spaceflight. Weinberg, on the other hand, has written more than one breathless polemic against HSF and especially against any government funding for it instead of particle accelerators.
I’m not one to appeal to authority regarding the future of spaceflight. These diametrical views by some smart individuals on the question of humanity’s future expansion into space illustrate why this is an issue of personal judgement and values, not something that can be settled purely by reasoned argument. There is no way to prove a priori that expansion into space is more or less important to humanity than other priorities and pursuits such as answering fundamental scientific questions.
As costs and other barriers to space expansion fall, those who want to go will go and those who want to stay behind will do just that. If human settlements thrive and develop robust new cultures, then they will have been a great success. If settlements fail and everyone comes back home, then they will have been a great failure. As every theoretician will tell you, it is real life experiment that ultimately answers important questions.