Tal Brewer is a philosopher whose area of con- centration is ethics; he is not a philosopher whose specialty is ethics. Philosophers don’t have spe- cialties; they aren’t specialists.
Why isn’t a philosopher’s area of concen- tration his or her specialty? The answer is connected with the fact that philosophers don’t speak with authority; they aren’t authorities in their field. That claim has to be qualified. A philosopher whose area of concentration is logic or some part of the history of philosophy can be described as specializing in that area and as being an authority. John Rawls was the most influential political philosopher of our times, but nobody speaks of him as an authority in political philosophy.