Editing Theophrastus (section)

=== Logic ===
Theophrastus seems to have carried out still further the [[grammatical]] foundation of [[logic]] and [[rhetoric]], since in his book on the elements of [[speech]], he distinguished the main parts of speech from the subordinate parts, and also direct expressions ({{lang|grc|κυρία λέξις}} {{Transliteration|grc|kuria lexis}}) from metaphorical expressions, and dealt with the emotions ({{lang|grc|πάθη}} {{Transliteration|grc|pathe}}) of speech.<ref>Simplicius, ''in Categ.'' 8.</ref> He further distinguished a twofold reference of speech ({{lang|grc|σχίσις}} {{Transliteration|grc|schisis}}) to things ({{lang|grc|πράγματα}} {{Transliteration|grc|pragmata}}) and to the hearers, and referred poetry and rhetoric to the latter.<ref>Ammonius, ''de Interpr.'' 53; Schol. ''in Arist.'' 108, 27.</ref>

He wrote at length on the unity of [[judgment]],<ref>Alexander of Aphrodisias, ''in Anal. Pr.'' f. 128, 124; Schol. ''in Arist.'' 184. 24. 183, b. 2; Boethius, ''de Interpr.''</ref> on the different kinds of negation,<ref>Ammonius, ''in Arist. de Interpr.'' 128; Schol. ''in Arist.'' 121. 18.</ref> and on the difference between unconditional and conditional necessity.<ref>Alexander of Aphrodisias, ''in Anal. Pr.'' f. 12. 6; Schol. ''in Arist.'' 149. 44.</ref> In his doctrine of [[syllogisms]] he brought forward the proof for the conversion of universal affirmative judgments, differed from Aristotle here and there in the laying down and arranging the ''modi'' of the syllogisms,<ref>Alexander of Aphrodisias, ''in Anal. Pr.'' 14, 72, 73, 82. 22, b, 35; Boethius, ''de Syll. categ.'' ii. 594. 5, f. 603, 615.</ref> partly in the proof of them,<ref>Alexander of Aphrodisias, ''in Anal. Pr.'' 39, b</ref> partly in the doctrine of mixture, i.e. of the influence of the modality of the premises upon the modality of the conclusion.<ref>Alexander of Aphrodisias, ''in Anal. Pr.'' 39, b. etc. 40, 42, 56, b. 82, 64, b. 51; John Phil. xxxii, b. etc.</ref> Then, in two separate works, he dealt with the reduction of arguments to the syllogistic form and on the resolution of them;<ref>Alexander of Aphrodisias, ''in Anal. Pr.'' 115.</ref> and further, with hypothetical conclusions.<ref>Alexander of Aphrodisias, ''in Arist. Anal. Pr.'' 109, b. etc. 131, b.; John Phil. lx. etc. lxxv.; Boethius, ''de Syll. hypoth.''</ref> For the doctrine of [[Proof (truth)|proof]], [[Galen]] quotes the second ''Analytic'' of Theophrastus, in conjunction with that of Aristotle, as the best treatises on that doctrine.<ref>Galen, ''de Hippocr. et Plat. Dogm.'' ii. 2.</ref> In different [[monograph]]s he seems to have tried to expand it into a general theory of [[science]]. To this, too, may have belonged the proposition quoted from his ''Topics'', that the ''principles of opposites'' are themselves opposed, and cannot be deduced from one and the same higher genus.<ref>Simplicius, ''in Categ.'' f. 5; Schol. p. 89. 15; comp. Alexander of Aphrodisias, ''in Metaph.'' 342. 30.</ref> For the rest, some minor deviations from the Aristotelian definitions are quoted from the ''Topica'' of Theophrastus.<ref>Alexander of Aphrodisias, ''in Top.'' 5, 68, 72, 25, 31.</ref> Closely connected with this treatise was that upon ambiguous words or ideas,<ref>Alexander of Aphrodisias, ''in Top.'' 83, 189.</ref> which, without doubt, corresponded to book Ε of Aristotle's ''Metaphysics''.<ref name="SmithDGRBM" />