What is called Reasoning by Analogy is one of the most elementary forms of reasoning, and the one which the majority of us most frequently employ. It is a primitive form of hasty generalization evidencing in the natural expectation that "things will happen as they have happened before in like circumstances." The term as used in logic has been defined as "Resemblance of relations; Resemblances of any kind on which an argument falling short of induction may be founded." Brooks says: "Analogy is that process of thought by which we infer that if two things resemble each other in one or more particulars, they will resemble each other in some other particular." Jevons states the _Rule for Reasoning by Analogy_, as follows: "If two or more things resemble each other in many points, they will probably resemble each other also in more points." Others have stated the same principle as follows: "When one thing resembles another in known particulars, it will resemble it also in the unknown;" and "If two things agree in several particulars, they will also agree in other particulars." There is a difference between generalization by induction, and by analogy. In inductive generalization the rule is: "What is true of the many is true of all;" while the rule of analogy is: "things that have some things in common have other things in common." As Jevons aptly remarks: "Reasoning by Analogy differs only in degree from that kind of reasoning called 'Generalization.' When _many things_ resemble each other in a _few properties_, we argue about them by Generalization. When a _few things_ resemble each other in _many properties_, it is a case of analogy." Illustrating Analogy, we may say that if in A we find the qualities, attributes or properties called _a_, _b_, _c_, _d_, _e_, _f_, _g_, respectively, and if we find that in B the qualities, etc., called _a_, _b_, _c_, _d_, _e_, respectively, are present, then we may reason by analogy that the qualities _f_ and _g_ must also belong to B.