Billie Eilish was interviewed by Terry Gross on “Fresh Air” yesterday and as she spoke about her appearance – and the thinking behind it – it occurred to me that she is the antithesis of Taylor Swift. And it struck me as odd that two of the biggest female singers were such polar opposites, both in their physical presence and their musical styles. (Pop music – a genre that contains multitudes.) Of the two, I find Eilish’s music the more interesting by far.