I have discovered that interest is an emotional response to the recognition of hidden similarities and differences. Human beings love to recognize the covert similarities and differences between things that are overtly, respectively, different and similar. When and only when we have this kind of recognition are we interested.
This definition of interest is not arbitrary. The process of comparing and contrasting, the ability to make associations and distinctions, is fundamental to the human mind. Upon this has depended the survival and satisfaction of the human race. Are you friend or foe? Although you look friendly, you talk the same as Killer Joe. Or perhaps one is interested in fine art because one has realized that a still life is composed, not of bananas and oranges, but of paint.
Interest is an analytical key to the structures of everything interesting. All human endeavors present conditions for interest in one of two ways: by juxtaposition —presenting both of two terms for comparison and contract, and by implication—presenting one term and implying or suggesting the other. A rhyme’s structure is juxtaposition; one recognizes in two different words a similarity in sound that marks a similar point in the rhythm or suggests a similarity in significance: “foe” and “Joe.” The structure of a still life of bananas and oranges is implication; one recognizes the similarities between the paint and one’s memories of the things the paint depicts.
Maybe I am interested in Christian communion because I feel that although wine and blood are obviously different things, nevertheless the wine of the sacrament is the blood of Jesus. A friend might catch my interest by asking “Aren’t we having a pun time?” I would laugh (if I hadn’t heard this before) because I expect the word “fun” and recognize the similarity and the difference between “fun” and the unexpected “pun.” Further, although I “know” that baseball “is only a game,” it interests me because it is not only a game—in some ways, it is life itself.
The capacity of anything to interest you, whether it is a matter of religion, humor, sports, or a matter of the arts, business, science, or personal relations, can be explained by this principle. Examine any two elements in or associated with the thing that interests you that are obviously similar or different, and see if your interest is in recognizing their hidden differences or similarities.