Today, I talked with somebody about reading speed. I asked him how fast he can read. He didn't answer, instead he said that the concept is abused by people. He said, it's more complicated than to say that you read at a certain reading speed. It depends on if you're reading a novel, a history textbook, or a poem.
I feel like he was falling into a kind of fallacy. He observed that a concept isn't entirely coherent, rejected the concept. However, the concept of reading speed seems real. It seems to capture something about reality.
This becomes obvious once you think about an experiment where we have two people that read the same material and time them. I read "The adventures of the Lightcone team" (or whatever it is called) together with Chu. We made the bed that I can get more than halfway through the book, before she finishes. I bet $5 on that. When she was finished, I almost managed to get halfway through the book. I was trying to read really fast, at the edge of comprehensibility.
Clearly there are latent causes, in each of our brains, that determine how fast we can read while still comprehending the text.
Trying to operationalize the concept that you're talking about, and imagining what sorts of experiments you would try to run to measure it, might be a good general way to avoid the fallacy of dropping a concept and losing its true kernel. Often you don't even need to run the experiment. Imagining it is sufficient.
Edit: see also this follow up comment.
As a psychometrician, I would think the case here is more complicated than that. Disclaimer: I'm not an expert on reading speed, so I might be wrong about some things here.
I agree with you that there are probably strong correlations between the speed at which different people can read different texts, to the point where it seems like it would make sense to rank people by reading speed in a fairly unidimensional way. However, I would also agree with him that the speed at which people read things depends on other factors, such as the kind of material one is reading, or the way one is reading it.
This becomes a problem when one has to quantify the reading speed. You can't exactly quantify reading speed as e.g. "words per minute", because the number will depend on other factors. And I bet there's no known natural unit to use for reading speed.
In psychometrics, you usually solve this by just working with relative rankings of people, rather than independently meaningful numbers. So for instance if there was two people whose reading speed you both know very precisely, where one of them is a very quick reader and one of them is a very slow reader, you could use proximity in reading speed to those two people to discuss it numerically. However, I think it is quite rare for people to have clear baselines like this? Idk.