These metaphysical entities, variously named Ideas, Notions, Concepts or Universals, may be divided into two kinds, sensuous and supersensuous.[17] The sensuous are those which may be apprehended by the senses, such as ‘red’, ‘cold’, ‘round’, ‘swift’, ‘painful’, and the supersensuous, those apprehended not in sensuous perception but otherwise. Logical relations, ‘necessity’ or ‘impossibility,’ and such ideas as ‘willing’, ‘end’, ‘cause’, and ‘being three in number’, have in this way been supposed to be directly apprehensible by the mind. Amongst these supersensuous Ideas good is to be found. Nothing could be simpler than such a view, and to many people the subsistence of such a property of goodness appears not surprising. But to others the suggestion seems merely a curious survival of abstractionism, if such a term may be defended by its close parallel with obstructionism. A blind man in a dark room chasing a black cat which is not there would seem to them well employed in comparison with a philosopher apprehending such ‘Concepts’. While ready for convenience of discourse to talk and even to think as though Concepts and Particulars were separable and distinct kinds of entities, they refuse to believe that the structure of the world actually contains such a cleavage. The point is perhaps undiscussable, and is probably unimportant, except in so far as the habit of regarding the world as actually so cloven is a fruitful source of bogus entities, usually hypostatised words. The temptation to introduce premature ultimates—Beauty in Æsthetics, the Mind and its faculties in psychology, Life in physiology, are representative examples—is especially great for believers in Abstract Entities. The objection to such Ultimates is that they bring an investigation to a dead end too suddenly. An ultimate Good is, in this instance, just such an arbitrary full stop.