In a recent post, the Maverick Philosopher touches on analagous reasoning. Since the post touches on analagous reasoning, the sort meant often by legal reasoning, or more simply "thinking like a lawyer," I figure those interested in either law or philosophy, or both, may be interested.
I'll say this about analogies. An analogy is a comparison. To have a comparison, you have to have two things. (One cannot compare a thing to itself). Given that there are two things being compared, there must be one or more properties in respect of which the two things differ.