 An implication of the ubiquitous nature of the overlap of classes is that the justification for the employment of philosophical concepts cannot be based on empirical observation because philosophical distinctions cannot be empirically verified. A geologist’s classification of rocks into sedimentary and crystalline, for example, is based on the observable features of the two types of rocks and is empirically verifiable; by contrast philosophical distinctions such as those between the expedient and the right, mind and body, cannot be similarly justified precisely because they are distinctions in the concepts without differentiation in the instances. The justification for the deployment of philosophical concepts and distinctions lies in the fact that they enable us to bring reality under different descriptions and view it from different angles, that they enable one, for example, to judge a work of art to be aesthetically beautiful and yet morally reprehensible.