the principles of law/ leadership/good government
Our science teachers created hands-on laboratories in which students can discover scientific principles.
The organization works on the principle that all members have the same rights.
Follow these two principles, [and] I'm sure you will become fit and healthy. (First Certificate in English; B2; Chinese)
She doesn't wear fur on principle.
They granted themselves a little celebration: it was time to keep the promise made four years before; so they bought some bottles of wine and got drunk (the[y] who, on principle, never drank alcohol). (Certificate of Proficiency in English; C2; Spanish)
They have approved the changes in principle.
In principle, one can agree with both positions pointed out in this statement. (Certificate of Proficiency in English; C2; German)
He must be punished - it's a matter of principle.
He cheated every time he had the slightest opportunity to, even when it wasn't necessary at all. It was a matter of principle to him. (Certificate of Proficiency in English; C2; Greek)