Alex,

While I understand your concern about conclusive evidence, I think a simple statistical sampling of lifeforms, a review of the original NRC report, Martian meteorites, and even some of Zubrin's examples ARE evidence (albiet) inconclusive that Martian life will not be hazardous. The evidence for a nonhazardous nature comes from general biology, actual extremophiles, and basic ecology not complex and untested theories of astrobiology. I'd be more than glad to discuss any specific examples you think do indicate a potential hazard or discuss any of the rationals why it is unlikely to be a hazard in more detail.

I see my judgement that a fresh out of school still single scientist is more likely to read journals than a mid career married engineer with three kids was correct. Amazing how you can make predictions without absolute scientific proof. Given that at least three are relevant to the debate and in particular questions of evolution, please tell me if you see any relevance of the biotechnology problem of modified gene loss to the potential hazardous nature of Martian organisms and whether or not you think D. radiodurans supports the idea that Martian organisms would be some kind of dangerous superbug capable of causing global disaster.

I'm not saying you should claim extremely low risk is the same as 0 risk. I'm saying you should not even begin to equate extremely low risk as "somewhere in between" BD and Zubrin. That's not being scientifically rigorous, it is being PC squishy. Do you honestly think there is significant chance of a major environmental catastrophe while at the same time think the odds of martian life being nonhazardous are low (defined here as being lower chance of being nonhazardous than being globally catastrophic)? Are these extreme viewpoints even in the same ballpark with respect to odds in your view?

We agree Zubrin should not dismiss the threat out of hand. I initially believed Zubrin's PR oped was primarilly dismissing BD out of hand while asking others not to over react to potential failure modes, I'm not so sure anymore based on his rebuttal. He had seen comments from me expressing concern for lack of explicit support for past NRC recommendations, but did not express support for them in his rebuttal to critics. That may have been due to space limitations and a higher priority on supporting his previous comments. Despite still being willing to give him some benefit of doubt, that oversite irritated me enough not to send the supportive letter I had written to PR.

Regards,
Mark