I've worked in Clinical Psychology and one of my consultants kept a copy of a demented new-age 'channelling spirits' book "Seth Speaks" by Jane Roberts [1] on her desk and was adamant that I read it.
My point is that "whether someone bases their arguments on rational, scientific grounding" cannot be determined by looking at their qualifications or their employment, especially when they are speaking outside of their field. Jordan Peterson's most famous claims - firstly about a conspiracy of Postmodern Marxism (which is a non-sequitur to anyone who has even a basic understanding of postmodernism or marxism) and the claims underlying his rise to internet fame - fearmongering about C-16 bill including being extremely misleading about the specifics of it - are absolutely not based on "rational, scientific grounding", and his CV doesn't change this.