Descartes and the Legal System?

In order for myself to fully understand the tremendous repercussions of Descartes writings on western thought I always try and find examples where functions of society and daily life were transformed in a realm that I have experience with. While thinking about the way that I know the world and how I exercise my individual reason I was reminded of when I was called to my civil contribution of jury duty. I wasn't excited to go to the government center every morning but thought it could be interesting to witness our legal system in the works. Being thoroughly convinced I wouldn't get called to any trial, let alone selected by the attorneys to have a seat on the jury, both of course happened. I presented myself accurately and was most likely chosen on the basis that I was an educated college student with experience growing up in the twin cities and therefore I was most likely liberal with my judgments. After two and a half weeks of trial and a full day spent of sequestered deliberation, myself and twelve others participated in the act of charging a person with murder without intention.

Everyone has judgments about the way they see and know the world that have been effectively established by our individual use of reason, however who's to say what's right if anything? The defendant was a black middle aged male that had been battling an addiction to crack-cocaine. I made the assumption that this was probably not the first encounter he had with the courts, which after the case was over, I learned the wrong assumption. My reason failed me. During investigations the police collecting the information and evidence used during trial were using their subjective intuition and reason to gather 'objective' information. Rather than using objective methods I noticed extremely faulty ways of finding, or not finding, evidence that seemed biased by on individual prejudices often associated with drugs and race. It was unclear what happened in the situation but what was clear was the investigation that held the weight of a human's future was conducted in a poor manner. Now, do you charge someone with this because you THINK they PROBABLY did it? A lot of it is speculation, which you are not allowed to use in the jury deliberation process. This act of speculation would not be available without Descartes. My reason led me to use all of the presented evidence and nothing else such as my understandings of what happened, or could have happened, basic intuition, feelings, experience, ideas about the world. A police officer is using all of these things when conducting the investigation that ultimately creates facts. So. Who gets to choose what's right? Why couldn't a jury collectively think outside of evidence? What happens if the police officer leading the investigating happens to hold an extreme opinion that effects his objectiveness, would he still create true facts?

The democratic practice of the legal system in and of itself would not be available without Descartes' belief in reason. During the middle ages, someone accused of murder would automatically be tortured or killed in return--no questions asked. Now the idea of a group of humans deciding a verdict that is the absolute truth seems to be something that is so readily accepted that it is rarely called into question, similar to how Scholastic philosophy was the functioning idea before Descartes. How can we use reason to critique or even think differently about dominating functions of human existence when we are living inside of that very existence?