I'm back and caught up in this thread. It appears that the only other person who doubts the feasibility of interstellar travel is Danial 1948. I don't buy any of the arguments proposed here for interstellar travel. It's naive to think that because we have overcome obstacles to travel to the moon or across vast open waters is anything comparable to interstellar travel. The scale of magnitude is at the least billions of times more complex.
I'll stick to the biology argument because that's what I know best. Consider the fish out of water metaphor for humans in space. Put a fish on a mountaintop and try to overcome the problem. The science as panacea crowd will put the fish in a tank but that has to be heated. Heat the tank but the fish needs to eat and is dependent on a coral niche. Okay.. add some coral but the coral are filter feeders and need plankton. Plankton and fish do not do well with UV radiation so put up a sunscreen..... and so on and on. The same metaphor is applicable to humans in space. Why is it so obvious to me that this will never happen while the majority, even the skeptics think it's feasible? I don't get it. Yes, humans are great survivors but put a human on the bottom of the sea or on top of an antarctic mountain and try to self sustain a colony there first. If we can do that, then attempting some absurd mission to planet "B" might be thought under a different light.
I'm not sure how to argue against this in any rational way, as it isn't an argument, and it isn't rational. I don't know why it is so obvious to you that it is impossible when you propose a few test cases for feasibility. Most of us in the thread suggest that a self sustaining space station is a more representative test than an undersea station (since we're talking about sustaining human life in space) but those are both useful, meaningful parallel efforts to stretch our understanding of what is possible (eta) and to differentiate 'impossible' from 'impractical' or 'too costly'. Practicality and cost are point-in-time characteristics, where impossibility (e.g., FTL) is not time dependent.(/eta)
You appear to be the only person who claims (in the negative) that science is a panacea (at least on this site). The rest of us seem to be claiming that science and technological advancement are vastly powerful, and part of the complex system of human endeavours.