Peter Hitchens:
A Review of 'The Diversity Illusion' by Ed West
"I simply don’t accept this. I think racial harmony is completely attainable, through the unifying force of a shared culture. The utter predominance of culture over ‘race’ is interestingly illustrated in reverse by this episode in Japan, about which I wrote (the full article is here
http://www.dailymail.co.uk/news/article-1192777/Welcome-rock-Hitchens-San-.html) in June 2009..."
He is not making the following argument, as if the second is a inference from the first - I think he is making two separate claims.
same ethnicity, but different culture --> seen as outsider
different ethnicity, but same culture --> seen as insider (= not seen as outsider)
e & ~c -> x
~e & c -> ~x
But would it be a sound argument? I would think not, but I don't want to revisit symbolic logic to show that this is the case.
At any right, I would argue that it is possible that ~e & c -> x. Why? Because even if culture is an important identifier for who is in your group, it may not be the only or the most important factor.