SCIENCE AND DEMONSTRATION 225 



strative premisses and the conditions of the demonstrative syllogism 

 which is productive of the highest form of knowledge Science. 



Not all knowledge that is certain is scientific in Aristotle s 

 sense of this term. Science he describes as knowledge of a thing 

 through its cause ; and an adequate knowledge of the cause, he 

 adds, will enable us to see that the thing cannot be otherwise than 

 it is. i 



Science, then, in the strict Aristotelean meaning of the term, 

 is apparently confined to a knowledge of things &quot; that cannot be 

 otherwise,&quot; z.. of abstract, metaphysically necessary truths, truths 

 that are in materia necessaria, that may not be denied without 

 violating some law of thought or involving some contradiction. 2 

 In ordinary modern usage, the term science includes our certain 

 knowledge of another vast body of truths, endowed with 

 a necessity of an inferior kind, not absolute but hypothetical, 

 contingent, physical. In a still wider sense, it embraces our 

 knowledge of moral, social, historical truths, etc., whose necessity 

 is based on the stability of the laws that govern human inter 

 course : truths about which we have moral certitude. 



252. NATURE AND CONDITIONS OF DEMONSTRATION. 

 Observing, in the next place, that we get science by Demonstra 

 tion, Aristotle describes the latter as a syllogism that engenders 

 science ; 3 and he then proceeds to lay down the conditions for a 

 cogent demonstrative, or apodeictic, syllogism : science, or demon 

 strated knowledge, must be inferred &quot; from premisses that are true, 

 ultimate, immediate, better known than, prior to, and causes of, 

 the conclusion ; from premisses that are the proper principles of 

 the demonstrated truth : for without such the syllogism will nof 

 be demonstrative, or productive of science&quot;. 4 



In the first place the premisses must be true ; for, &quot; though 

 formally a true conclusion may be got from false premisses, the 

 error still infects the mind, and will lead to a false conclusion 



8 oMfittf tKaffrov air\ias . . . 6rav t4\v r alriav olia/j.fvOa yiyviaffKtiv 

 8t tjv rb irpaynd iffnv, 8rt fKtivov alria fffn, Kal /xij 4i&amp;gt;$exf&amp;lt;T0ai TOUT a\\&amp;lt;as x etl/ Anal. 

 Post., i., cap. ii., i. In the term &quot; cause &quot; Aristotle here includes the four great classes 

 of cause, formal and material, efficient and final. Cf. Anal. Post., ii., cap. x. [xi.], i. 



2 Cf. DE MARIA, Logica (and edition), pp. 258, 259, 269 ; ZIGLIARA, Logica, (41). 



3 Qafifv 5e Kal Si &7ro5ei ews flStvai. Airo Seifu Sf \tyo&amp;gt; ffi/AAi-yiffjubi/ tiriaTT]noviM&v. 

 ibid., i., cap. ii., 3, 4. 



4 Ei Tolvvv 4ffT\ rb liriffTaaOai olov t8f/j.fv, avdyitr) Kal T^V OTroSei/cTi/c^J 4iriffTr)/jiri&amp;gt;&amp;gt; 

 ^{ a.\T)f)G&amp;gt;v T elvai KO.\ irptaruif Kal d/xetrcoi/ Kal yvupifMtartpeai/ Kal irporepuv Kal alriwv rov 

 (TVfj.irfpdff/j.aTOs OVTU yap tffovrai Kal al apx&amp;lt;*l oiKtiai rov SfiKvv/jievov. 2v\\oytar/*bs fi.fi&amp;gt; 

 yap tffrai Kal avfv TOVTCOV, diro Seifis 5 OVK ?crrai ov yap irorfiffft iiriariinriv, ibid., 5, 6. 



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