[LINK] Reinventing Explanation: Data Presentation as Intuition Pump
A great article by Michael Nielsen on failures of intuition and ways to present data more effectively so that we don't get caught by those failures. It reminded me of concepts like log odds in common use around here, and also to the recent discussion of teaching rationality techniques to average people.
I don't think I've ever used a text that didn't. "We have" is "we have as a theorem/premise". In most cases this is an unimportant distinction to make, so you could be forgiven for not noticing, if no one ever mentioned why they were using a weird syntactic construction like that rather than plain English.
And yes, rereading the argument that does seem to be where it falls down. Though tbh, you should probably have checked your own assumptions before assuming that the question was wrong as stated.