Here's more of a series of questions by a thoughtful person who meets my definition of a scientist: someone who may not have a degree in science, but constantly wonders about - and studies - the world around her/him.
Q: ...as you point out well, our job titles or status titles never will adequately reflect the complexity of the human mind. I appreciate the humble response, because you're right, and I know many individuals that fit your plumber example very well. Intelligence is something that can't be restricted by any persons "title." I didn't mean this response to be so long because I actually had another question!
So, even though I know geology focuses on earth based phenomena, I have to think you probably have good insights into the first place we might most likely find extraterrestrial life in our solar system. Titan, fitting name, seems to dominate the conversation that I have seen. But this seems much more extreme to life as we know it than something like Europa to me where what I have heard postulated is a possible underwater ocean/theremal vent type scenario where some extremophiles could potentially reside. And that nicely correlates with things we have seen on earth. I have just felt that Europa seems a bit left out, even though extremophiles in methane lakes on Titan is awesome and intriguing.
A: I concur completely: Titan is intriguing, but frozen methane-based life, if it exists, will not be meaningful to carbon-oxygen-water-based life (us) except in the abstract (as in: gee whiz). Europa has all the necessary ingredients: water, complex organic chemistry (clear from the colored streaks on the surface), and heat (the huge tidal gravitational gradient from too-nearby Jupiter). However, if we thought it was expensive and complex to get Curiosity operational on Mars, it will be one or two orders of magnitude more expensive to get something working in (and able to report back from) the ocean beneath the frozen crust of Europa.