realism

 1) An argument from divisibility
Primary qualities,unlike secondary qualities, are inseparable from objects. If you were to constanly divide up a grain of wheat it would lose its secondary qualities but maintain it's primary.

When we explain the changing colours of a table we appeal to the length and motion of particular light-waves. In contrast, secondary qualities are not part of our scientific explanationsoftheworld;itfollows,therefore,thattheyarenotpartoftheworld.