You probably meant that there doesn't exist a total order for comparing intelligence and/or that it isn't a scalar quantity like height, but "linear" didn't convey that meaning.
Intelligence clearly isn't a scalar quantity like height, the implication is that a faux scalar quantity like IQ or other ordinal scale doesn't well describe intelligence.
I agree, I think any test that gets you a meaningfully different result if you take it twice or are coached beforehand isn't measuring something intrinsic or meaningful, I'm just trying to help bridge a miscommunication.
Ranking people by "intelligence" is compounded by it being multifactored, language skills and numerical skills can differ independently, spatial skills are a third vector unaligned with either.