A Thought Experiment - I

[D17]

Let's have a little experiment and consider what'd be nescessary on an alien planet for life to exist and thrive. Post what conditions you think would be nescessary on the planet.

I'll start by saying the most obvious: Liquid Water.

[DaleyPaley]

Perhaps a moon to stabilise the orbit and a big gas giant neighbour to soak up stray comets and meteors. That's what the rare earth hypothesis says anyway.
Personally, I think it might be a little too limited; assuming conditions for earth life to be conditions for all life.
However, those things do indeed work well for us. 

[D.SCoub]

Ive never understood the significance of questions like this.  The answer is so obvious that Im not sure what lesson or insight were supposed to gleam from this. 

Its the same with the oft-repeated moral question about the train track and the five people tied up.  It essentially asks if you would be willing to push another man in front of a train to stop it from hitting the five people tied up.  Apparently people say they wouldnt do it because they have to actively push the person, rather than just flipping a switch and letting him die, which is the second scenario that people are in fact willing to do.  This moral "dilemma" has never made sense to me.  I see both actions as actively killing the person, because unless you hit that switch, the man gets to live.  But apparently other people dont see it that way.

This particular question seems very straight forward to me.  If its not H20, then its not the same as what we call water.  However, that doesnt mean that the twin Ai is not allowed to call his XYZ liquid "water" if he wants to.  The term "water" is meaningful only to people who live on Earth and speak English.  But again, apparently thats not the same conclusion other people come to?  Also, whats the point of this thought experiment?  What is it supposed to tell us?