Hmm interesting. it appears that you have ran into some type of argument against IQ tests, where people fear some type of judgement. I am not making that argument.
There are actual real instruments than can measure an apple precisely. Using a ruler would be good for an informal guess that gives a rather good result. But nowhere near what a machinists calibers could give you. As far as that apple decaying and changing size; that can be derived through the proper equations. All in all I can help to notice that you are bending over backwards making excuses for a flawed test. If an IQ test is at best subjective then its conclusions have no intellectual meaning. We are not trying to measure a objects size (like an apple). We are trying to quantify human intelligence. The subject matter no matter the "tool" is itself at best subjective.
A person who has not aquired a formal education as an adult will always score low on any IQ test that is commonly used. An adult from the bush in some third world country may not possess the knowledge needed to even take an IQ test. But you cannot that the results of an attempted test as a measure of that persons intelligence. If you are merely using IQ tests to predict social outcomes then you are not measuring intelligence at all. You are trying to measure the ability of the subject to conform to the world around him. Those are social skills that are dependent on a lot of variables other than intelligence. The main deterrent to success is an education. If you cannot afford higher education you are a lot less likely to succeed in a major way. The lack of success is not an indicator of intelligence.
There are some arguments that intelligence isnt a trait but really something that is taught. Though obvious mental disorders and physical problem can objectively reduce intelligence. The are solely argues that there really are not people higher intelligence. No one is really born with magical powers. An artist isnt born an artist it learned.
