A re-casting of Alexander's Three-Fold Path of pattern languages, for design engineering.
The information about Alexander's 3-fold path is drawn largely from [App98]. First, a summary of Alexander's 3-fold path is given; then, a “translation” into my perspective is given.
The essence of all things living and useful that imparts unto them qualities such as: freedom, wholeness, completeness, comfort, harmony, habitability, durability, openness, resilience, variability, and adaptability. It is what makes us feel “alive” and “sated”, gives us satisfaction, and ultimately improves the human condition.
The mechanism that allows us to reach the quality. It is manifested as a living common pattern language that permits us to create multiform designs which fulfill multifaceted needs. It is the universal “ether” of patterns and their relationships that permeate a given domain. The gate is the conduit to the quality.
Using the way, patterns from the gate are applied using a technique of differentiating space in an ordered sequence of piecemeal growth: progressively evolving an initial architecture, which then flourishes into a “live” design possessing the quality. Alexander likens it to a “process of unfolding, like the evolution of an embryo, in which the whole precedes the parts, and actually gives birth to them, by splitting.” By following the way, one may pass through the gate to reach the quality.
A design that satisfies not only its technical requirements, but that also is suited to a market, represents a good business tactic, satisfies a societal need, and that addresses issues such as aesthetics, usability, etc. as well as 'fitting' into a global context has a certain appeal - a balance - that makes it greater than just the sum of its parts. There are no known methods for assuring an engineering design is well-balanced, yet they remain the ideal of all designers, and are readily identified where they exist.
A pattern language gives an architecture for human cognitive design functions to temper creativity with reason, and to provide coarse-grained guides to direct the creative energies of designers. A pattern language is a tool that augments designers' innate and learned skills by suggesting potentially successful routes and providing warnings to pitfalls and problems.
A top-down, systems-based approach of beginning designing by considering the role to be played by the product in a larger context, and then detailing the product to satisfy those requirements.