8 TEMPORAL ORGANIZATION IN CELLS 



terms and for the present problem this means to use functional equations 

 instead of differential equations, and to look for invariant measures rather than 

 invariant integrals. However, this is rather difficult mathematical ground, and 

 much of the analytical apparatus remains to be discovered or constructed. 

 The step from differential equations and invariant integrals to functional 

 equations and invariant measures would give the theory a much greater degree 

 of representational accuracy, allowing one to treat heterogeneous rather than 

 homogeneous systems, and systems with time-lags and hysteresis effects. It 

 also involves a "quantization" of the "energy" states. Such an extension 

 may prove to be essential before the theory can be experimentally significant; 

 but it seems useful and necessary to explore the classical side of the programme 

 in order to develop some familiarity with the type of concept which is likely 

 to emerge from this approach to the integrated behaviour of intracellular 

 systems, and the sort of phenomena for which to look in testing the theory. 

 Only thus can it be decided whether or not the approach is fundamentally 

 correct. 



