Roy Simpson wrote to me as follows:
"Nigel,
I have found some links to books by Rosen - which I haven't seen referenced in your AI papers. Some of the ideas here are interesting from my Penrose (-related) computability work, although also he is trying to model biological systems mathematically.
Here is one link on his key definition of the distinction between simple and complex systems. Simple systems have all Turing-computable models whereas complex systems (the interesting ones for life modelling) have non-computable models.
I actually found this book via a route involving Prof Bernie Cohen's pages. I am wondering whether to order the book and give it a proper study. Then there might be the question of relating it to your reactive systems etc.
Roy."
--- My Reply ---
If you do order it, and review it with a healthy dose of skepticism,then I think that would be interesting.
There's a long, quasi-Marxist tradition of philosophical-conceptual analysis of biology. I remember back in our STL days Bernie and myself were much enamoured of Francisco Varela who coined the term 'autopoietic system' (self-producing systems) and wrote a book about it which leveraged universal algebra and category theory.
God, how we studied and discussed that book! (Principles of Biological Autonomy - now almost unobtainable: try instead Autopoiesis and Cognition: The Realization of the Living).
However, I am now inclined to believe that these paradigms - although fascinating - flatter to deceive and that they truly add little fundamental insight. I would be deliriously happy to be proven wrong!
NOTE: One of the concepts given extended treatment by Varela was Spencer-Brown's Laws of Form. In its 'mystical and declamatory prose' Spencer-Brown's work was entirely aligned with the quasi-Hegelian, dialectical approach of this whole school of thought. The maths retains an interest however.