If my only criterion in choosing a programming language was to make myself smarter, I would probably choose Prolog or a similar language. I find that when I'm

If my only criterion in choosing a programming language was to make myself smarter, I would probably choose Prolog or a similar language. I find that when I'm writing Prolog I am forced to think precisely about the problem at hand. The reason for this is that the programs one is writing are basically just specifications of the truth conditions that constitute a solution to the problem. Other languages (especially those with flexible syntaxes) make me feel more mentally limber due to the amount of creativity they encourage. But Prolog is the only language I've ever written that makes me feel like I might actually tack on an IQ point.