So, you see, in general Abstraction we form two classes: (1) the unlike and not-general qualities; and (2) the like or common qualities. As Halleck says: "In the process of Abstraction, we draw our attention away from a mass of confusing details, unimportant at the time, and attend only to qualities common to the class. Abstraction is little else than centering the power of attention on some qualities to the exclusion of others.... While we are forming concepts, we abstract or draw off certain qualities, either to leave them out of view or to consider them by themselves. Our dictionaries contain such words as purity, whiteness, sweetness, industry, courage, etc. No one ever touched, tasted, smelled, heard, or saw purity or courage. We do not, therefore, gain our knowledge of these through the senses. We have seen pure persons, pure snow, pure honey; we have breathed pure air, tasted pure coffee. From all these different objects we have abstracted the only like quality, the quality of being pure. We then say we have an idea of _purity_, and that idea is an abstract one. It exists only in the mind which formed it. No one ever saw _whiteness_. He may have seen white clouds, snow, cloth, blossoms, houses, paper, horses, but he never saw _whiteness_ by itself. He simply abstracted that quality from various white objects." In Abstraction we may either (1) abstract a quality and set it aside and apart from the other qualities under consideration, as being non-essential and not necessary; or we may (2) abstract a quality and hold it in the mind as essential and necessary for the concept which we are forming. Likewise, we may abstract (1) all the qualities of an object _except one_, and set them aside that we may consider the _one_ quality by itself; or we may (2) abstract the one particular quality and consider it to the exclusion of all its associated qualities. In all of these aspects we have the same underlying process of considering a quality apart from its object, and apart from its associated qualities. The mind more commonly operates in the direction of abstracting one quality and viewing it apart from object and associated qualities.