The adversarial system is rigid – the roles are proscribed – the prosecutor wants to convict, the defendant wants a decision of not guilty. They are not just allowed but expected to bias their presentation, trusting the truth to come out between the adversaries. Science certainly has its sides of partisanship and bias. But these sides are self-imposed and can be abandoned at any time. While a prosecutor should not lie or hide evidence, and should drop a case if they become convinced the defendant is innocent, they wake up in the morning with no choice about which side of the argument they will come down on. In the criminal justice system the advocates are rigidly fixed in their roles and the jurors are rigidly neutral (the process to find a random neutral jury took as long as the trial itself). In science, the advocates are the same people as the jurors. And as a result they have to be willing to be flexible and change their minds. A good scientist shouldn’t have a pre-determined rigid answer to a question.
Lack of investigation – we jurors were told over and over not to investigate the situation ourselves. We were to make our decision only on the basis of the evidence presented to us. I can tell you in the case I was on there were at least two whopping big questions hanging over the case that nearly every juror in the room identified as very important but not addressed by either lawyer. Either one of them (whether the defendant’s schedule allowed time to drink before being stopped in the car, whether a particular medical condition could affect breathalyzer tests) could have changed the outcome. We could have answered one of these with 10 minutes on google and the other with some very simple subpoena of records. But we couldn’t use any of this. Scientists obviously are the opposite – if they need more information, they are expected to go get it before making an opinion.
Reliance on personal testimony – although science and trials share a focus on evidence, trials recognize testimony of individual people under oath as a major form of evidence. They certainly acknowledge the possibility of lying and explicitly instruct jurors to decide what testimony they believe. My case was unusual in that there was so much video footage, but still a majority of the case came down to testimony by the police officers, and most cases even a few years ago would have had only testimony. Science on the other hand, doesn’t accept testimony. Or does it? What else is the methods and results section of a paper? I’m on the fence whether science is so different on this one.