re: Science, yes. Truth, no (till proven).
I found the article to be very thoughtfully written (despite the author's use of a (social) evolutionary metaphor). He doesn't state that science is only observation but that theorist should keep in mind that they are theorizing about physical phenomena which must have some direct or indirect observables against which the theory can be tested. Otherwise, the theory is simply mathmatics, art or theology. While speculating about pre-big bang may be interesting and even important, until that speculation can be tested, it is not science.
Dave M