Coming from a biology background, this is the exact sort of catch-all statement I really despise. Is there purity? No, not in the absolute sense. However, we'r

Coming from a biology background, this is the exact sort of catch-all statement I really despise. Is there purity? No, not in the absolute sense. However, we're not some homogeneous mix either. Genetic, environmental and other such patterns do form a number different subgroups which while imperfect, remain useful.