Planning as a scientific activity faces a double challenge. First, it must understand its social reality (as differentiated from the reality of nature). Second, it must understand its own role in constituting that socially constructed reality, which is also its object of study. This is not an easy challenge, and it carries planning well beyond its traditionally defined role, both as a academic as well as a professional activity. These boundaries were transgressed briefly in the 1960’s, so there is a glimpse of what could be done. But planning would have to sharpen its understanding, not only of the society into which it is intervening, but also of its own rhetorical resources for intervening in socially and politically responsible ways.