The bulletin of mathematical biophysics

, Volume 5, Issue 4, pp 115–133

A logical calculus of the ideas immanent in nervous activity

  • Warren S. McCulloch
  • Walter Pitts

DOI: 10.1007/BF02478259

Cite this article as:
McCulloch, W.S. & Pitts, W. Bulletin of Mathematical Biophysics (1943) 5: 115. doi:10.1007/BF02478259


Because of the “all-or-none” character of nervous activity, neural events and the relations among them can be treated by means of propositional logic. It is found that the behavior of every net can be described in these terms, with the addition of more complicated logical means for nets containing circles; and that for any logical expression satisfying certain conditions, one can find a net behaving in the fashion it describes. It is shown that many particular choices among possible neurophysiological assumptions are equivalent, in the sense that for every net behaving under one assumption, there exists another net which behaves under the other and gives the same results, although perhaps not in the same time. Various applications of the calculus are discussed.

Copyright information

© The University of Chicago Press 1943

Authors and Affiliations

  • Warren S. McCulloch
    • 1
  • Walter Pitts
    • 2
  1. 1.College of Medicine, Department of Psychiatry at the Illinois Neuropsychiatric InstituteUniversity of IllinoisUSA
  2. 2.The University of ChicagoChicagoUSA

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