on love, iii. [338];
on materialism, ii. 176;
on mathematics, 323;
on metempsychosis, 303;
his method, i. 239;
on music, i. 336;
on nature of nothing, i. 529;
on the nature of the philosopher, i. 21, 41, 109, 143; ii. 369, 374;
on plants, iii. [34];
on punishment, i. 451;