The Compendium of Caraka 1.10.24

1.10.24

caturvidhavikalpāśca vyādhayaḥ svasvalakṣaṇāḥ /
uktā mahācatuṣpāde yeṣvāyattaṃ bhiṣagjitam //

and the fourfold classification of diseases with their respective characteristics,
upon which therapeutics depends, have been declared in the Great Chapter on the Four Pillars.