52 SCIENTIFIC METHOD IN PHILOSOPHY 



two instances of jealousy, but only one. It is in such 

 cases that I speak of a relation of three terms, where the 

 simplest possible fact in which the relation occurs is one 

 involving three things in addition to the relation. And 

 the same applies to relations of four terms or five or any 

 other number. All such relations must be admitted in 

 our inventory of the logical forms of facts : two facts 

 involving the same number of things have the same form, 

 and two which involve different numbers of things have 

 different forms. 



Given any fact, there is an assertion which expresses 

 the fact. The fact itself is objective, and independent of 

 our thought or opinion about it ; but the assertion is 

 something which involves thought, and may be either 

 true or false. An assertion may be positive or negative : 

 we may assert that Charles I. was executed, or that he 

 did not die in his bed. A negative assertion may be said 

 to be a denial. Given a form of words which must be 

 either true or false, such as " Charles I. died in his bed," 

 we may either assert or deny this form of words : in the 

 one case we have a positive assertion, in the other a 

 negative one. A form of words which must be either 

 true or false I shall call a proposition. Thus a proposition 

 is the same as what may be significantly asserted or 

 denied. A proposition which expresses what we have 

 called a fact, i.e. which, when asserted, asserts that a 

 certain thing has a certain quality, or that certain things 

 have a certain relation, will be called an atomic pro- 

 position, because, as we shall see immediately, there are 

 other propositions into which atomic propositions enter 

 in a way analogous to that in which atoms enter into 

 molecules. Atomic propositions, although, like facts, 

 they may have any one of an infinite number of forms, 

 are only one kind of propositions. All other kinds are 



