Mathematical universe or mathematical minds? It is not actually a question, but a subject for debate related to the title of the post: If somehow evolution has equipped us with mathematical minds, it is fair to hypothesize that the "book of nature is written in the language of mathematics" just because we see it that way. Of course, this does not account for answers to other philosophical problems related to applicability of mathematics (such as Wigner's puzzle). Still, the (philosophical) investigations to such problems tended to ignored those biological-anthropocentric factors. If I have to draw a question, it would be this: Can theoretical philosophy be more multi- or inter-disciplinary at least for this topic? Isn't it that philosophy generally avoid science in collaborating on philosophical topics?