11 ideas
| 9540 | A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell] |
| 9541 | The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell] |
| 9543 | The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell] |
| 9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
| 12312 | The real essence of a thing is its powers, or 'dispositional properties' [Copi] |
| 10937 | Essential properties are the 'deepest' ones which explain the others [Copi, by Rami] |
| 12308 | In modern science, nominal essence is intended to be real essence [Copi] |
| 12303 | Within the four types of change, essential attributes are those whose loss means destruction [Copi] |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| 12307 | Modern science seeks essences, and is getting closer to them [Copi] |
| 12310 | Real essences are scientifically knowable, but so are non-essential properties [Copi] |