Antonym for apophenia
I wouldn't call this reference authoritative, but after a bit of research the first article in this journal (originally published in the Journal of Parapsychology) introduces the term "randomania" as "attributing chance probability to (apparently) related phenomenon." Note that this term is specifically defined in contrast to apophenia.

As an aside, this blog post discusses the history of the term apophenia (and potential modern misapplications of its current definition).