The old software development methods are outcomes of linear thinking, reductionism, the superposition principle, and the Constructive holism principle that the parts of a software system will be developed first, then the parts will be integrated into the whole of the software system.
        Differently, NSE software development method is based on complexity science and the Generative holism principle that the whole of a system will be generated first as an embryo, then the system will grow up incrementally - in this way all versions are executable and that customers' testing can be performed early to get customers' feedback early.
        “Incremental development – grow, not build software … that the system should first be made to run, even though it does nothing useful except call the proper set of dummy subprograms. Then, bit by bit it is fleshed out, with the subprograms in turn being developed into actions or calls to empty stubs in the level below.”[Bro95]

Reference

[Bro95] Brooks FP Jr (1995) The mythical man-month. Addison-Wesley, Reading.