(CNN) -- If trials were predictable, they wouldn't happen. You can root for a jury to see a case your way and disagree with its ultimate verdict, but you cannot criticize the jury system for being unpredictable. In that sense, a Florida jury's recent verdicts -- and nonverdicts -- against Michael Dunn demonstrate a fundamental truth about trials. They are not only unpredictable; they are designed that way. The case against Dunn stemmed from an incident on November 23, 2012. Dunn, a 47-year-old white man, arrived at a gas station in Jacksonville, Florida, and parked next to an SUV that contained Davis and other black teenagers. When Dunn complained about loud music coming from the SUV, words were exchanged and Dunn ultimately fired a gun that killed Davis. Dunn said he saw a gun barrel pointing out of the SUV, but the prosecution said there was no gun.
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Danny Cevallos: Critics of the Michael Dunn verdict miss a feature of trials
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They're always unpredictable, and it's impossible to get inside the mind of a jury, he says
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He says jury may have been unsure about meaning of various degrees of homicide
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Cevallos: The prosecution scored a win, despite public criticism of the verdict
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Even if Dunn's testimony were completely believed, at best only @placeholder was the aggressor, so Dunn had a minimal self-defense claim against the other occupants.
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On one hand, they have achieved a virtual life sentence on the other convictions, which achieves one of the philosophical goals of punishment: incapacitation and isolation of @placeholder from the community.
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It does not achieve another goal of punishment for the @placeholder family: retribution.