RUN RUN AWAY: Jubal Harshaw, Robert Heinlein's alter ego, refers me to this Chicago Tribune story about William Heirens, who may or may not be a serial killer. Harshaw says:

William Heirens, then a bright high school student, and since the first prisoner in Illinois to get a college degree behind bars, was charged with triple murder in 1946. He was injected with sodium pentothal, and, WHILE UNDER THE INFLUENCE OF THE PENTOTHAL made a “confession” that eventually led to his conviction. There were “inconsistencies” in the physical evidence presented, and prosecutors admitted that they would have had a hard time convicting him without the “confessions.” Though another man had already confessed to the murders, Heirens is still in prison, now 78 years old.

For those of you who haven’t seen someone injected with sodium pentothal, let me try to explain the problem here. Sodium pentothal, aka “truth serum” makes people tell the truth only in the comic book world. Here in the real world, it does NOT make people tell the truth. In low doses, sodium pentothal can make people babble incoherently, and frequently repeat whatever they are told (an event called "echolalia"). Imagine being bone-tired, drunk, and stoned, all at once. What someone says under the influence of sodium pentothal has as much relation to the truth as what you would expect to come out of the mouth of someone who’s been awake for 48 hours, just finished with a fifth of scotch, and on his tenth doobie.

There does seem to be a real divergence of opinion regarding this guy though, about whether he did it or not. But Harshaw's point about a sodium pentathol confession being evidence is obviously right. There's a point here about the limits of science, and about a bygone era where people could believe there was a clear test, like an injection or the polygraph, that would prove if people meant what they were saying beyond a shadow of a doubt. But that never happened and we still have to make up our own minds about what people are really thinking based on their words and actions until we all evolve giant brains and vestigial legs and have super-monkeys build us wheelchairs. So it goes.