I'm willing to bet "life" on other planets is exceedingly rarer than we would like to believe, and possibly non-existent within a finite universe (at least in terms of how we choose to define "life").

The problem with the Drake equation that's quite popular is that I think it's too broadly defined. Given how incredibily complex the basic building blocks of "life" is, the probability of the same biological mechanisms repeating even under the same environmental conditions is very, very slim.

Even the simplest single cell organism is incredibly complex. DNA is not a simple structure.....to suggest that every carbon molecular process elsewhere in the universe even under similar earth like conditions will coalesce into what will eventually be the helix structure of DNA>genes>single cell organisms (and beyond) is probably statistically far beyond the scope of the drake equation. That's not to say it's impossible, I'm just saying if all the variables were properly take into consideration you might find the chance of life occuring is statistically one of out a number possibly more than the number of stars in the known visible universe.

I'm not saying "life" doesn't exist elsewhere. I think our definition of life is too narrow and the type of life we're looking for we may never find. (carbon based, oxygen/water/temperature environmental prerequisites, the notion of single or multi cell organism, etc). Just because you have water & oxygen on a planet with ambient temperature & pressure as ours, doesn't mean life MUST form. All life on planet earth (plants and animals) can be traced back to a common ancestor. There isn't a single carbon based life form on our planet that's outside of that ancestral history, which would be quite common if these earth-like conditions were in fact a needed prerequisite. Likewise, who's to say Venus (or any other planet/location that we consider "hostile" in environment) can't be a catalyst for "life" in the future that utilizes a totally different set of environmental conditions?