Sorry, newbie here. I assume that once you've fleshed our your similarity cluster, your initial clue may also be happily proven false, right?
I'm thinking of, say, amputees, or, ahem, furries, neither of which would match your clue, but both of which can be recognised (perhaps with some difficulty in the latter case) as humans, once you've gathered enough information to fill out your cluster.
Erratum? I'm pretty sure your machine learning example set should have Cloudy as the sky attribute in the third line; otherwise your machine learner won't match any value for the sky attribute.