Being able to communicate ideas that are “potentially interesting enough” across disciplines is critical for integrating sciences.

In “Towards a Theoretical Biology” (Nature, 1968), Waddington outlines discussion points held at two symposia instigated by the International Union of Biological Sciences with support from the Rockefeller Foundation:

Theoretical physics is a well recognized discipline…Moreover, it is widely accepted that theories of the nature of the physical universe have profound consequences for problems of general philosophy.  In contrast to this situation, theoretical biology can hardly be said to exist as an academic discipline.  There is even little agreement as to what topics it should deal with, or in what manner it should proceed…

The International Union of Biological Sciences has felt that it is its duty…to explore the possibility of formulating some skeleton of concepts and methods around which theoretical biology can grow…Essays arising from the first meeting have been published under the title Towards a Theoretical Biology (renamed, “Origin of Life”, JR)…the volume arising from the second meeting will appear...

Pattee raised a question…which seemed perhaps rather recondite to many of the biologists present.  The stability of the algorithms stored in DNA is ensured by quantum mechanical processes which define the configuration of single DNA molecules.  Their replication and decoding depend on the actions of enzymes, such as polymerases, which ensure that the bases in a single strand of DNA are paired up correctly with the complementary based to form the second strand or the corresponding RNA.  The existence of such enzymes cannot, he claims, be deduced from the fundamental laws of physics. 

They are acting as “non-holonomic” constraints to limit the degrees of freedom of the whole system.  Their origin at some very early stage of evolution is one of the major problems…We are confronted therefore with an example of a “quantum measurement”, a matter which seems to cause theoretical physicists many headaches.

The essential dependence of a hereditary system on the existence of non-holonomic constraints on the degrees of freedom is one example of a class of problems which appeared in several different guises during the discussions.  A non-holonomic constraint may be regarded as a part of a physical system which has a very long relaxation time in comparison with the remainder of the system.

Bastin, considering the nature of the concept of hierarchy of levels of organization…argued that the only logical way in which it is possible to discriminate a number of activities into a hierarchy is by considering their reaction times… there is a real intellectual task to be carried out by theoretical biologists in formulating a scheme of thought adequate for discussion of the global epigenetic properties of entities as complex as higher organism cells…

Evolution was perhaps the most central theme throughout the whole discussions.  Many physicists seem ready to concede that the principle of natural selection imparts to the biological world a type of logical structure, which they scarcely meet in their own field of interest.  Biologists, however, while gratified to be told that physicists admit that biology offers problems which actually need thinking about, still remain doubtful whether physicists have realized just how challenging these problems really are…

So, can you help clarify and update Waddington’s characterization of nonholonomic constraints? 

What does this have to do with path-dependence or chreods in context of cell differentiation or developmental patterning?

Why is this thing worthy of special mention? 

Would you mind speculating on why it matters for advancing integrative science like cancer physics, physical biology or developmental biology?