That when you’ve already picked someone/something out from the general population based on a particular property you cannot then use the same criteria to come to conclusions.
If you use a DNA matching technique with a 1 in a million chance of a false positive to pick your suspect out of a large database of people you cannot then use that “1 in a million chance” as part of the evidence against them. Yet courts absolutely would. (doing it the other way round, selecting one person then using the test is perfectly reasonable)
That when you’ve already picked someone/something out from the general population based on a particular property you cannot then use the same criteria to come to conclusions.
If you use a DNA matching technique with a 1 in a million chance of a false positive to pick your suspect out of a large database of people you cannot then use that “1 in a million chance” as part of the evidence against them. Yet courts absolutely would. (doing it the other way round, selecting one person then using the test is perfectly reasonable)