I shouldn't be sure that I'm right about a lack of evidence making life on other planets "essentially a guarantee"? Yeah, I'm feeling okay about that claim especially given the contradictory "evidence" presented thus far.
Don't pretend like the "essentially a guarantee" comment was pertinent to our discussion. I was talking specifically about microbial life with that comment, and I made that comment later and out of context to the discussion we were having. This debate hasn't fundamentally changed in the slightest since that comment.
Aside from the lack of any evidence to base an "extrapolation" on besides "But it's really big!", you mean.
Yeah. Wishful thinking. But I do admit that one uses bigger words so I guess it sounds like it might be more true provided you don't think about it.
We have sufficient evidence for inferential extrapolation-- we have US, and we have our observation rate. Currently, at best we can conclude that life exists on 1 out of roughly 400 planets observed out of roughly an extrapolated ~1 billion unobserved planets (based on stars:planets). Because we have yet to observe a statistically significant sample of subjects, inference is the only tool we have to rely on. Essentially, at this point we have more reason to believe that 1/1000 planets have life on them than to believe that NO other planets have life on them. That's not tautology, unless you think that inferential extrapolation is tautological. If you'd like to argue that point, I'd welcome the discussion.
I'm pretty sure he's not arguing that no life exists outside Earth. He's arguing that there's not enough evidence to say either way. It may be somewhat likely, but you're saying it's nearly certain.
Are you referring to Drake's equation in this instance?
His assertion, if I understood it correctly, was that evidence pointed to it not being the case, which is a claim that can really only be made with regards to an assumption like normality where we don't have nearly enough data to employ a test of normality. However, if we were to extrapolate data to assume normality, it would be more likely that there were life elsewhere than not.
This confusion about me saying that it is "nearly certain" should be clarified. I'm not actually saying that, and my statement was outside of the current context of the discussion. Shinta said that the probability of life elsewhere (which I took to include the simplest life) was enough to entertain reasonable doubt, and I replied that it was "more like" essentially certain. So we can quibble about it or suspect me of backpedaling, but my intention was not to express that the probability of life was =.999999999, but to say that reasonable doubt (which could be =.05 for all I know) is less like the actual likelihood than .9999999 is. e.g., if it's safer to guess a likelihood of something like .7.
As for Drake's equation, no, though that looks like it has some fundamental similarities. I just made a cursory glance of the wiki on it, but it doesn't factor in certain pertinent data and seems to ignore statistical normality more or less completely. It could probably be adapted easily enough to express something with actual substance though. I would agree that it relies on too many unknown data points to be at all useful. You can only extrapolate so far-- the more you extrapolate on extrapolated data, the weaker your case, though you can still have a decent one with prominently extrapolated figures (and in most cases in the natural world where the data is known, it does in fact work). That equation starts from one data point (which is smaller than the figure you would use for the purposes of our discussion) and extrapolates everything else. I wouldn't say that it's totally useless, but practically useless.
Ok, now we're going to get slash fiction of Wint x Kachi somehere... rule 34 and all...
Never confuse your inference as the listener for an implication of the speaker.
Good games are subjective like good food is subjective. You're not going to seriously tell me that there's not a psychological basis for why pizza is great and lutefisk is revolting. The thing about subjectivity is that, as subjects go, humans actually have a great deal in common.