Therefore, some A is C . Here A denotes real estate, B denotes increase in value, and C denotes a good investment. Just as in the case of this example, every syllogism consists of two premises and one conclusion. All A is B . The letters A , B , C are known as terms .
Every syllogism contains three terms.
The two premises always share a common term which does not appear in the conclusion. This is known as the middle term . In our real estate example, the middle term is B , i.e., that which increases in value. In order to classify the various types of syllogisms, one must take account of certain symmetries. Furthermore, the order of the two premises in a syllogism does not matter.