Defining psychology: is it worth the trouble?

Henrique's thoughtful effort (this issue) to define psychology suffers from at least three shortcomings: (a) "psychology" is almost certainly an inherently fuzzy concept that resists precise definition; (b) attempts to define psychology are likely to hamper rather than foster consilience across scientific disciplines; and (c) Henriques incorrectly diagnoses the cause of the scientist-practitioner gap and hence offers an incorrect prescription. The sources of this gap lie not in intractable definitional disputes, but in fundamentally different approaches to acquiring knowledge.