what is meant by "physical" in distinction from other adjectives that are prefixed to subject-matter is precisely an abstraction of alimited range of conditions and relations out of atotal complex. The same principle applies to mathematical objects. The use of symbols designating possible operations makes possible agreater degree of exactness and intellectual organization. There is no disparagement of ab- straction involved. Abstraction is simply an instance of the economy and efficiency involved in all intelligent practice: Deal first with matters that can be effectively handled, and then use the results to go on to cope with more complex affairs. Objection comes in, and comes in with warranted force, when the results of an abstractive operation are given astanding which belongs only to the total situation from which they have been selected. All specialization breeds afamiliarity which tends to create an illusion. Material dealt with by specialized abstractive processes comes to have apsychological independence and completion which is converted hyposta- tized into objective independence and self-sufficiency.