There are some things that there is no reliable scientific data on. Almost any argument is going to rely on these things in some way. E.g. Black people commit

There are some things that there is no reliable scientific data on. Almost any argument is going to rely on these things in some way. E.g. Black people commit much more crime per capita than White people. Some people might consider it common sense that no amount of discrimination by the justice system could account for such a gap. Other people might say the opposite: there is so much specific evidence of discrimination that we should expect the overall system to be extremely biased. Sure, specific studies might fill the gap, but more questions will be raised about the details of those studies, and the cycle continues. While we should use all available evidence, at the end of the day we need more information than object evidence can provide, in order to form opinions about important topics.