[akudha]

I am terrified of affecting someone's health, freedom or money (especially health and freedom) unknowingly, mistakenly etc. How do people who lie in court, use unproven tools etc to screw someone's entire life sleep at night? This is so far beyond my comprehension.

[Bluestrike2]

Well, for starters, they don't actually think their junk science is junk science. If you're confident that you were right all along, and you nailed the "bad guy," you're going to sleep just fine. All of these people believe they're helping further the cause of justice; very few go to work thinking "this is bullshit, I know it, and I don't care." Given their training and experience--even though it's experience in a field we later define as junk science--they become confident in their own work, and confirmation bias is omnipresent. Not just for individual cases, but for entire forensic fields and methods.

It's not exactly the same, but there have been countless examples of prosecutors and police officers who, when faced with convictions overturned due to DNA evidence, continued to maintain that the person was nevertheless guilty despite that evidence. And if I'm being totally honest, I can't even imagine how tempting that fantasy would be.

The alternative is acknowledging that you got it wrong and an innocent person paid an extraordinary price for your failure, losing years of their life behind bars. Worse yet, your failure allowed allowed the actual murderer/rapist/etc. to get off scot-free and potentially harm others.

It's terrifying enough to imagine screwing up a single case. Now imagine screwing up hundreds or possibly thousands, after spending years using what you believed to be forensic science that turned out to be little more than bullshit. In that light, the temptation to search for alternative explanations, fight against information and evidence that contradicts your theory of the case, etc. has to be overwhelming. And while there are absolutely people in the justice system who don't succumb to that temptation, there are plenty who do.

[dragonwriter]

> Well, for starters, they don't actually think their junk science is junk science.

For starters, they don't actually care. If it will provide an excuse which can arbitrarily and selectively be cited to justify action, they will embrace it and train their officers on it; if public belief in it is likely to lead to more deference to law enforcement and fear of crime, they will also blast it in their PR (see magic fentanyl). If it will provide an excuse for actions that woild otherwise seem to violate civil rights, they’ll also invest heavily in it.

Truth isn’t relevant to many od the things police agencies pay to train officers on; power is. And the people—often former law enforcement themselves—crafting and selling these ideas know the market they are targeting.

[20after4]

They convince themself that the person is really guilty (of something, maybe not even the thing they are accused of, just generally bad / evil / wrong color / wrong religion. really whatever it takes for them to believe someone deserves punishment) .... then the ends justify the means.