HMS Barham wrote:Can you make your point more explicit? I can't parse "These gradients no not conform to racial categorizations.". This statement seems to have many possible meanings, some of which are true, some of which are false.
The variation we observe in human physiology does not conform to what we would expect if races were valid taxonomic groupings.
HMS Barham wrote:My taste in food is measured by my revealed preferences for food when I am given a free choice. Similarly intelligence is measured by ability to perform mentally-loaded tasks when under pressure to do so. They're both physical things.
They're not physical, since as you yourself point out we can only measure them indirectly, through the way they make us act. Intelligence part of the emergent function of an extremely complex set of genes and the environment and epigenetics interacting to form our consciousness.
HMS Barham wrote:Races clearly do correspond largely to independently evolving groups separated by geographical barriers. Even if they didn't, though, that would neither 1. make the socially constructed labels "invalid" nor 2. mean that those groups are all the same interchangeable.
They don't, though. There is and always has been gene flow between all of the different 'racial' groups. Asia to Europe, Asia to the Americas, Europe to Africa, Africa to Asia and so on. 1.) It does, though. The whole point of 'races' is that they're supposed to be valid taxa - ways to categorize humans according to our understanding of the evolution of humans. If they aren't valid taxa, then they're just simply wrong, in the same way that categorizing people based on the four humours is wrong. 2.) No-one here is arguing that humanity is uniform. What we're arguing instead is that the diversity we see in human physiology and genetics does not conform to what we would expect to see if races were taxa.
HMS Barham wrote:I don't think species, as it is used in either common speech or scientifically, is consistently defined. To say something is part of a species is much more a social statement than to say that someone is white. To say that blacks and whites are different species is primarily a political statement. It's not a statement I am making, but I can't say it's strictly false either - it's indefinite.
There are many ways to define species, yes. The problem is that the races don't mesh with any of them, as I pointed out. You can use the colloquialism instead all you like, but that just relegates you to the same bin as people who call lemurs monkeys.