However, constructivism is often associated with pedagogic approaches that promote active learning, or learning by doing. There are many critics of "learning by doing" (a.k.a. "discovery learning") as an instructional strategy (e.g. see the criticisms below). While there is much enthusiasm for constructivism as a design strategy, according to Tobias and Duffy "... to us it would appear that constructivism remains more of a philosophical framework than a theory that either allows us to precisely describe instruction or prescribe design strategies."