「原则上」用英语怎么翻译才准确合适?

应该就是「in principle」,我怀疑「原则上」很可能是从英语而来的说法,虽然找不到什么证据。英语里 in principle 同样表达「泛泛而论应如何、但并不意味着就不能有特例」:
in principle

Fundamentally, in general, but not necessarily in all particulars. For example, The diplomats accepted the idea in principle but would rely on experts to work out all the details . [Early 1800s]
-- In principle ,最下方 American Heritage 习语词典。中文使用习惯与此基本一致。「军训原则上不允请假」的意思是「军训不应该请假,但是学员母亲病重要请也可以答应」;或「甲方原则上同意乙方的提案」的意思是「但并不是每一个条款,其具体细节还需要商量」。

至于 technically:technically 在日常口语里用于强调某件事是「作为事实而成立的」或「严格来说的」:Technically, China and Taiwan are still at war
原发布于 https://www.zhihu.com/question/23234319/answer/24009146