I did a little digging and even started reading "System design from provably correct constructs: the beginnings of true software engineering". From what I can s

I did a little digging and even started reading "System design from provably correct constructs: the beginnings of true software engineering". From what I can see, it's mostly garbage used to sell the products of the HOS company. James Martin was on the board Higher Order Software, Inc. A company that despite claiming being able to provide "bug free software" went out of business. Here's Edsger Dijkstra debunking the books written about HOS. https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/EWD852.html https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/E... An evaluation by the US Navy concluded. "the HOS literature tends to advertise their ideas and products more than making a contribution in substance to the field of Computer Science. The author recommends that USEIT not be used in the TRIDENT program or any program development at NSWC. Even for a high level system specification, USEIT is not seen as a good choice. A mathematical functional notation or a PROLOG-like notation appears better suited for that purpose. The examples in the Appendices of this report, especially Appendices C, D, and E, show that a LISP-style mathematical notation is more compact and normally easier to read than the control map notation of USEIT. On a more positive note, the author considers the functional approach to system development and programing very promising. Systems so conceived and programs so constructed are more amenable to analysis and therefore, in principle, more reliable and better manageable." http://www.dtic.mil/dtic/tr/fulltext/u2/a198753.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/a198753.pdf So are we just talking about functional programming when we say HOS? If so, the pros and cons of functional programming have been discussed at great length. Here is an interview with Simon Peyton Jones (one of the creators of Haskell) talking about why Haskell is "useless". It's a short interview worth watching if you want to understand the nuances and challenges and costs around creating high quality and bug-free software. https://www.youtube.com/watch?v=iSmkqocn0oQ https://www.youtube.com/watch?v=iSmkqocn0oQ