In Favor of Robert Downey, Jr.'s Childhood

A Goldblog reader, fed up with my Just Say No advice column, writes in to argue against marijuana moralizing:

I would hope you would evaluate marijuana use on the basis of scientific studies more than on government policies and general societal beliefs.  Societies and governments have been wrong about major issues in the past (slavery, alcohol prohibition in the 1920s, lax labor laws just to name a few examples). ... Rather than supporting the puritanical position that you either completely abstain from marijuana or you must be raising the next Robert Downey Jr., it would be more constructive to live in the real world and realize the best approach to this issue is to say that while you don't encourage the use of this drug as there are some risks inherent in marijuana use, if you are going to use this drug, you should use moderate amounts and take reasonable safety precautions.