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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
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.
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".

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