It is a peculiar fact and rule of concrete concepts that (1) the larger the class of things embraced in a concept, the smaller are its general qualities; and (2) the larger the number of general qualities included in a concept, the smaller the number of individuals embraced by it. For instance, the term "bird" embraces a great number of individuals--all the birds that are in existence, in fact, but it has but few general qualities, as we have seen. On the contrary, the concept "stork" has a much larger number of general qualities, but embraces far fewer individuals. Finally, the individual is reached, and we find that it has more qualities than any class can have; but it is composed of the smallest possible number of individuals, one. The secret is this: No two individuals can have as many qualities _in common_ as each has individually, unless they are precisely alike, which is impossible in nature. IMPERFECT CONCEPTS. It is said that outside of strictly scientific definitions very few persons agree in their concepts of the same thing. Each has his or her own concept of the particular thing which he or she expresses by the same term. A number of persons asked to define a common term like "love," "religion," "faith," "belief," etc., will give such a variety of answers as to cause wonderment. As Green says: "My idea or image is mine alone--the reward of careless observation if imperfect; of attentive, careful, and varied observation if correct. Between mine and yours a great gulf is fixed. No man can pass from mine to yours, or from yours to mine. Neither in any proper sense of the term can mine be conveyed to you. Words do not convey thoughts; they are not vehicles of thoughts in any true sense of that term. A word is simply a common symbol which each associates with his own idea or image."