Caeteris paribus means "all else being equal" yet, terminologically, also stands in for "all else unchanged". I'm interested in knowing actually how to say "all else unchanged" in a way that bears resemblance to caeteris paribus.
The third part of Descartes's Principia Philosophiae (pg. 78 of this edition) contains a more literal translation of "all things unchanged":
Si autem caeteris immutatis, contingat ut minuatur illa vis...
Note that I only found 150 G-hits for this phrase: I highly recommend the (almost) exactly equivalent and far more prevalent ceteris paribus. If you are writing in English, I would especially discourage using caeteris immutatis.
Also, note that ceteris (without an a) is a much more common spelling.