On choices of three factors of analogy

Tang Jian-min has put forward the three factors of analogy: source of analogy, outcome of analogy, and knowledge unit of analogy, and has made preliminary research on the choices of source of analogy and knowledge unit of analogy. This text is deepened one step on the basis of research of Tang's, and carry on systematic research about the choices of outcome of analogy, especially regard mathematics knowledge as source of analogy. In author's view, the choices of source of analogy, outcome of analogy and knowledge unit of analogy concern the understandings of analogy target; determine the size and meaning of the analogy achievement. So study how to choose three factors of analogy concern the success of the analogy, its meaning is not definitely second to the proposition of three concept themselves.