Simplicity, Complexity, Unexpectedness, Cognition, Probability, Information
by Jean-Louis Dessalles
(created 31 December 2008, updated June 2016)
Simplicity and necessity
The notion of necessity generalizes the notions of desires and beliefs. It measures how much a state of affairs is believed or wanted. It closely corresponds to the intuitive notion of ‘necessity’.
Necessities are negative in case of disbelief or avoidance.
Necessities represent beliefs or desires. They change sign through negation.
Necessities come from the negation of situations that are emotional and/or unexpected.
A situation s may be ascribed necessity values νi(s) from two sources
Lastly, necessities may be propagated from consequence to cause (Dessalles, 2015).
- The necessity of the negation ¬s of s is: ν(¬s) = –ν(s).
A given situation s may receive different necessity values from different sources. They may add up. However, when deciding about actions or beliefs, necessities of opposite sign create a cognitive conflict that leads to deliberative reasoning and argumentation (see Dessalles, 2015). During the deliberative procedure, necessities may be transferred from consequence to cause to propagate cognitive conflict.
- The emotion attached to a consequence t of s is a source of necessity for s: ν3(s) = ±(E(t) – Cw(t|s)) (if E(t) > Cw(t|s)).
The sign of ν3(s) corresponds to the valence of the emotion.
Dessalles, J.-L. (2008). La pertinence et ses origines cognitives - Nouvelles théories. Paris: Hermes Science.
Dessalles, J.-L. (2015). A Cognitive Approach to Relevant Argument Generation. Computational Models of Natural Argument (CMNA-15). Bertinoro, I: .
Back to the Simplicity Theory page.