Letters from Ross Ashby to Jacques Riguet.

Ross had a correspondence with the French mathematician Jacques Riguet between 1953 and 1959. Unfortunately, we do not have Riguet's replies, however, it is clear that Riguet's work resonated with Ross's own approach so well that Ross suggested they consider writing a book together on the theory of biological relations.

1. Ashby to Riguet, 20-Apr-1953, 1 page
2. Ashby to Riguet, 19-May-1953, 3 pages
3. Ashby to Riguet, 29-Oct-1954, 2 pages
4. Ashby to Riguet, 5-Jun-1959, 5 pages

For more informtion about Riguet and cybernetics in France in the 1950s, see L'impossible constitution d'une théorie générale des machines? La cybernétique dans la France des années 1950 by Ronan Le Roux.

Journal references to Riguet

Although there is no first-level index card for Riguet in Ross's alphabetical index, Ross mentioned Riguet many times in his Journal's summaries and second-level index entries. Those Journal entries are included below, interleaved chronologically with the letters to help show how Ross was influenced by Riguet.

Relation binary Summary: Riguet on binary relations. 4470, 4498, 4566, 4581, 4604, 4632 4436 4437

Letter 1: Ashby to Riguet, 20-Apr-1953, 1 page

Letter 2: Ashby to Riguet, 19-May-1953, 3 pages

Summary: The unreliability of introspective evidence. Equilibrium Riguet's definition 4740 4741

Trajectory Riguet's definition Basin algebraic definition 4742 4743

Regulation implies both activity and non-activity Summary: Riguet's statement of "relational mechanics." 4751 4748 4749

Dependence Riguet's definition Independence Riguet's definition Summary: Coordinates and projections in relational form. 4756 4757

Summary: Riguet's definition of "dependance". 4813, 4992 4758 4759

Trajectory Riguet's definition Summary: Riguet's "trajectory" is practically my "transient". 4760 4761

Joining tensor calculus of Machine Riguet's definition Tensor product of two machines 4766 4767

Summary: Machines, with inputs and outputs, treated wholly by mappings. All this is, in substance, identical with Riguet's form. 4867. Simpler 4876, 4991 Evolution as process Natural Selection [83]: Huxley and Fisher on Evolution (extracts from book) 4861. Summary: Feeding a machine with input and output back into itself. 4860 4861

Dependence Riguet's definition Diagram of immediate effects (D.I.E.) Riguet's formulation Independence Riguet's definition 4992 4993

Letter 3: Ashby to Riguet, 29-Oct-1954, 2 pages

Algebra of coupled systems Summary: Formally stated method of coupling by using the tensor product of Riguet. 5098 5099

Basin and tilde operation Kernal relation (Riguet), =Noyau 6086 6087

Letter 4: Ashby to Riguet, 5-Jun-1959, 5 pages

Summary: The concept of feedback being positive or negative is usefully simple only when the system is continuous. 6184 [Goes in small steps - Riguet 6184] 6177 6178

Requisite Variety, Law of in Pandemonium Oddments [46]: Carry out the program of pages 6184 (foot) and 6185 (top). Summary: Selfridge's Pandemonium and pattern recognition. 6222 Confluant generalisation of step-function Step function what matters is the confluent Oddments [46]: Carry out the program of pages 6184 (foot) and 6185 (top). Summary: I should re-read my Notes, Vol. 5 or so onwards, reading "lots of step-functions" as the more general "lots of equilibria", and lots of step-surfaces" as "lots of boundaries of confluents". 6184 6185