پیچیدگی

روز به روز بر پیچیدگی مسائل و راهکارهایی که با آنها روبرو می‌شویم، افزوده می‌شود. این موضوع مختص نرم‌افزار نیست. تا دیروز برای فهم سیستمی مانند انبار کافی بود که یک هفته وقت صرف گردد،‌ مطئمن بودید که با صرف زمانی می‌توانید به تکنولوژی نوظهوری تسلط نسبی پیدا کنید. اما حالا چطور؟

“The challenge over the next 20 years will not be speed or cost or performance; it will be a question of complexity.” Bill Raduchel

“Our enemy is complexity, and it’s our goal to kill it.” Jan Baan

“In the presence of essential complexity, establishing simplicity in one part of a system requires trading off complexity in another. We can master essential complexity, but we can never make it go away.” Grady Booch

در کنار همه تبعات موضوع پیچیدگی، یکی از محدودیتهای مهم برای روبرو شدن و غلبه بر پیچیدگی، محدودیتهای انسانی است. برای روشن شدن موضوع، بخشی از کتابObject-Oriented Analysis and Design with Applications را انتخاب کرده و در زیر آورده‌ام.

The Limitations of the Human Capacity for Dealing with Complexity
…However, there is yet another factor that dominates: the fundamental limitations of the human capacity for dealing with complexity.
As we first begin to analyze a complex software system, we find many parts that must interact in a multitude of intricate ways, with little perceptible commonality among either the parts or their interactions; this is an example of disorganized complexity. As we work to bring organization to this complexity through the process of design, we must think about many things at once. For example, in an air traffic control system, we must deal with the state of many different aircraft at once, involving such properties as their location, speed, and heading. Especially in the case of discrete systems, we must cope with a fairly large, intricate, and
sometimes nondeterministic state space.

Unfortunately, it is absolutely impossible for a single person to keep track of all of these details at once.

Experiments by psychologists, such as those of Miller, suggest that the maximum number of chunks of information that an individual can simultaneously comprehend is on the order of seven, plus or minus two. This channel capacity seems to be related to the capacity of short-term memory. Simon additionally notes that processing speed is a limiting factor: It takes the mind about five seconds to accept a new chunk of information .

We are thus faced with a fundamental dilemma. The complexity of the software systems we are asked to develop is increasing, yet there are basic limits on our ability to cope with this complexity. How then do we resolve this predicament?

گزیده:

The only source of knowledge is experience. Albert Einstein