Traditional engineering is decompositional in nature. To understand the whole, first decompose the whole into the constituent parts. Then master the individual constituent parts, put them back together again, and the whole is now understood. The understanding of the whole is the sum of the understanding of the parts.
A good example of traditional engineering is a car. Break the car down into its parts such as the steering sub-system, the transmission, the engine, the brakes, and many more sub-systems. The mastery of each of these sub-systems, leads to the mastery of the car. The whole (in this case, the car), is completely mastered by examining the parts in isolation and then looking at their combination to form the whole.