LOGIC AS THE ESSENCE OF PHILOSOPHY 53 



more complicated. In order to preserve the parallelism 

 in language as regards facts and propositions, we shall 

 give the name " atomic facts ' to the facts we have 

 hitherto been considering. Thus atomic facts are what 

 determine whether atomic propositions are to be asserted 

 or denied. 



Whether an atomic proposition, such as " this is red," 

 or " this is before that," is to be asserted or denied can 

 only be known empirically. Perhaps one atomic fact 

 may sometimes be capable of being inferred from another, 

 though this seems very doubtful ; but in any case it 

 cannot be inferred from premisses no one of which is an 

 atomic fact. It follows that, if atomic facts are to be 

 known at all, some at least must be known without 

 inference. The atomic facts which we come to know in 

 this way are the facts of sense-perception ; at any rate, 

 the facts of sense-perception are those which we most 

 obviously and certainly come to know in this way. If 

 we knew all atomic facts, and also knew that there were 

 none except those we knew, we should, theoretically, be 

 able to infer all truths of whatever form. 1 Thus logic 

 would then supply us with the whole of the apparatus 

 required. But in the first acquisition of knowledge 

 concerning atomic facts, logic is useless. In pure logic, 

 no atomic fact is ever mentioned : we confine ourselves 

 wholly to forms, without asking ourselves what objects 

 can fill the forms. Thus pure logic is independent of 

 atomic facts ; but conversely, they are, in a sense, 

 independent of logic. Pure logic and atomic facts are 

 the two poles, the wholly a priori and the wholly 



1 This perhaps requires modification in order to include such facts as 

 beliefs and wishes, since such facts apparently contain propositions as 

 components. Such facts, though not strictly atomic, must be supposed 

 included if the statement in the text is to be true. 



