Liliana Albertazzi, in the Introduction to her Handbook of Experimental Phenomenology (Albertazzi 2013), explains that there are "two main "classical' versions of phenomenology: the Husserlian and the experimental version of Stumpf and Michotte", i.e. "the outstanding tradition of experimental inquiry which culminated in Gestalt psychology". Albertazzi then raised the following problems: "what is the difference between the two classic versions of phenomenology", and are they "incompatible with each other, in that one pertains to philosophical analysis and the other to science", or rather are they "in some way concordant"? (ibid., pp. 1 f.)