What is the theoretical basis of Patterns?
No formal basis in the usual sense. Patterns can express design notions stemming from all sorts of theoretical and empirical bases. On the other hand, many of the notions of pattern-directed design stem from classic and not-so-classic works on “design theory” across diverse fields of engineering. (See the bibliographies of papers listed in the Patterns Home Page.) • Can patterns be expressed in [SOME PARTICULAR FORMALISM OR NOTATION]? You are welcome to try, but bear in mind that a representation of a design or design rule in some formal notation is not a pattern if it omits descriptions of context, the problem(s) it solves, evidence for adequacy of the solution, construction or implementation guidelines, or relations with other patterns. • Why should I use patterns? For the same kinds of reasons that you should reuse good code: Benefitting from the knowledge and experience of other people who have put more effort into understanding contexts, forces, and solutions than you have done
