DEMONSTRATION AND SELF-EVIDENCE 25 



notion of potential being (which in a sense represents a middle 

 ground between being simpliciter and non-being simpliciter) . 

 In a similar fashion he defends the integrity of discourse by- 

 introducing the notion of the self-evident proposition. Self- 

 evident propositions are the basic truths of demonstration, and 

 in them scientific conclusions exist in potency. The demonstra- 

 tive movement represents a true advance in knowledge from 

 the potentiality of the scientific conclusion to its actuality. 

 Prior to discourse the conclusion is not known simpliciter; but 

 at the same time it is not unknown simpliciter. It is potentially 

 known in its principles. The actual grasp of the self-evident 

 proposition is the potential grasp of the scientific conclusions 

 virtually contained therein. The premises of demonstration — 

 taken as premises, that is, seen together to involve a middle 

 term — function after the fashion of efficient causes which 

 actuate the potentiality of the conclusion and make it be.^° 

 The whole of the Posterior Analytics is concerned to investigate 

 the logical vehicle (namely, demonstraton) which brings us 

 from the self-evident principles to our scientific conclusions. 

 In the first book demonstration and its types and properties 

 are investigated. The second book concentrates on definition 

 precisely as the medium of demonstration. Quite significantly 

 the last chapter of this second book — which completes the 

 Posterior Analytics — comes full round to the topic of the very 

 first chapter. Meno's dilemma is absolved in terms of the uni- 

 versally necessary and immediate basic principles of discourse. 

 Scientific conclusions are truly conclusions insofar as they are 

 different from these basic truths but are generated from them. 

 They are truly scientific insofar as the basic truths of discourse 

 into which they are resolved are primary and incontrovertible 

 affirmations of the real. Upon the integrity of these basic truths 

 or principles of demonstration depend the integrity of demon- 



*" Quodl., Vni, a. 4; " Insunt enim nobis naturaliter quaedam principia primo com- 

 plexa omnibus nota, ex quibus ratio procedit ad cognoscendum in actu conclusiones 

 quae in praedictis principiis potentialiter continentur. . . ." Cf., also De Ver., q. 11, 

 a. 1; Surmna, I, q. 117, a. 1. 



