If you agree with or believe something in principle, you agree with the idea in general, although you might not support it in reality or in every situation.

In principle I agree with the idea, but in practice it's not always possible. 我大体赞成这个想法，但实际上这并非总是可行。

They have approved the changes in principle. 他们基本上批准了这些变革。

We were willing in principle to offer her a room in our house.

The terms of the contract were agreed in principle last week.

In principle, ministers believe that a national ID card scheme would have major benefits.

See also: principle (IDEA)