Now the question comes back to how it can be related to Software Engineering. To answer this question lets look at a Software System. A Software System comprises of many small - small independent functional modules. Each module performs a specific task.
While designing a Software System if we break a big system into smaller and independently managed modules who can work in isolation our task becomes simpler. The whole system can then be developed easily and tested in its own right.
Atomic theory also implies that a system is whole of its parts. It means the systems behaviour is the combined behaviour of all its parts or sub-systems.
Until Next Time...