Full Idea
Mind is compelled by necessary truths that can't be regarded as false, but not by contingent ones that might be false.
Clarification
'Necessary' truths must be true, 'contingent' truths only happen to be true
Gist of Idea
The mind is compelled by necessary truths, but not by contingent truths
Source
Thomas Aquinas (Quaestiones Disputatae de Malo [1271], Q6.h to 12)
Book Reference
Aquinas,Thomas: 'Selected Philosophical Writings', ed/tr. McDermott,Timothy [OUP 1993], p.182