"We lack any sort of device that can... detect life. We don't have a life meter. ...We don't have a general pupose life meter that can detect life as we don't know it. Obviously, if it's life as we know it, there are all sorts of features. ...NASA plans a mission to... ... which has a plume of organic material spewing out, and they want to fly through that plume... The question is, what are they going to put onboard that would return a result "Yes, we have found life"... How would you do that? What exactly do you measure?"