No, it doesn’t. It only requires the assumption that 1) such people score slightly more poorly, and 2) employers begin choosing employees from the tail end of the distribution. A slight difference in scores on the test will reduce the percentage at the tail end out of proportion to the size of the difference. I don’t remember the formal name for this, but it’s very well known.
I will not quibble about what constitutes ‘devastatingly poor’ beyond observing that I of course agree that the difference need not be numerically large in order to be devastating. I will again point out that you are assuming that there is sufficient bias in the IQ test that if used (instead of whatever other form of measurement or selection could be adopted) the change will be devastating. That is a significant claim, particularly when it is quite possible that subjective evaluations of intelligence by interviewers are more biased than IQ tests. I expect IQ may be somewhat racially biased. I know for certain that unstructured human arbitration is racially biased. I don’t know for sure to which is worse but do observe that it is sufficiently controversial that some evidence is required.
You asked the reader to imagine a world where some assumption holds—which is fine as far as it goes. It becomes an error in reasoning when you jump from “imagine...” to “a good case” without providing evidence that the imaginary scenario applies to reality. Even the bare statement “I assert that IQ tests are more racially biased than whatever is used in their stead” would have made the case at least coherent, albeit still weak.
The argument was in response to the implicit assumption that even if the tests are biased, we shouldn’t worry about that as long as they can predict performance. “Imagine” takes the place of the word “if” in there and the intended conclusion is “yes, you should worry about whether the tests are biased, because if they are biased, that would be bad.” To make that conclusion I do not need to provide evidence that the imaginary scenario applies to reality.
If I say “imagine that you jumped off a cliff. You’ll get smashed. Maybe you should avoid jumping off cliffs”, I don’t need to provide evidence that you jump off cliffs, because the conclusion is in the form of a conditional that already conditions on whether the imaginary scenario is real.
I will not quibble about what constitutes ‘devastatingly poor’ beyond observing that I of course agree that the difference need not be numerically large in order to be devastating. I will again point out that you are assuming that there is sufficient bias in the IQ test that if used (instead of whatever other form of measurement or selection could be adopted) the change will be devastating. That is a significant claim, particularly when it is quite possible that subjective evaluations of intelligence by interviewers are more biased than IQ tests. I expect IQ may be somewhat racially biased. I know for certain that unstructured human arbitration is racially biased. I don’t know for sure to which is worse but do observe that it is sufficiently controversial that some evidence is required.
You asked the reader to imagine a world where some assumption holds—which is fine as far as it goes. It becomes an error in reasoning when you jump from “imagine...” to “a good case” without providing evidence that the imaginary scenario applies to reality. Even the bare statement “I assert that IQ tests are more racially biased than whatever is used in their stead” would have made the case at least coherent, albeit still weak.
The argument was in response to the implicit assumption that even if the tests are biased, we shouldn’t worry about that as long as they can predict performance. “Imagine” takes the place of the word “if” in there and the intended conclusion is “yes, you should worry about whether the tests are biased, because if they are biased, that would be bad.” To make that conclusion I do not need to provide evidence that the imaginary scenario applies to reality.
If I say “imagine that you jumped off a cliff. You’ll get smashed. Maybe you should avoid jumping off cliffs”, I don’t need to provide evidence that you jump off cliffs, because the conclusion is in the form of a conditional that already conditions on whether the imaginary scenario is real.