By the 1960s analytical philosophers also became aware of the Sapir–Whorf hypothesis, and philosophers such as Max Black and Donald Davidson published scathing critiques of Whorf's strong relativist viewpoints. Black characterized Whorf's ideas about metaphysics as demonstrating "amateurish crudity". According to Black and Davidson, Whorf's viewpoint and the concept of linguistic relativity meant that translation between languages with different conceptual schemes would be impossible. Recent assessments such as those by Leavitt and Lee, however, consider Black and Davidson's interpretation to be based on an inaccurate characterization of Whorf's viewpoint, and even rather absurd given the time he spent trying to translate between different conceptual schemes. In their view the critiques are based on a lack of familiarity with Whorf's writings; according to these recent Whorf scholars a more accurate description of his viewpoint is that he thought translation to be possible, but only through careful attention to the subtle differences between conceptual schemes.