Sunday, August 14, 2011

Criticism, Falsifiability and Rationality

1. As a reader, one should be able to expect an author to have done his homework and get an attribution right.

I began reading Neil B. MacDonald's Metaphysics and the God of Israel being annoyed by his incorrect attribution.

In the Prologue of his book, MacDonald attributes the idea that falsifiability is a criterion of rationality to Karl Popper.

The attribution is false.

It is well known that Karl Popper proposes falsifiability as a criterion to demarcate between science and non-science.

Popper did not use falsifiability as a criterion for rationality.

Rather, the closest thing Popper used as a criterion for rationality is criticism.

2. MacDonald wrote (2006, xxii):

I mention two famous classical criteria of rationality. Descartes' criterion of certainty and Karl Popper's criterion of falsifiability:

(1) One ought not to believe something unless the belief is certain. This criterion says that it is irrational to believe something if the belief inquestion is not certain. We therefore require unassailable foundations. (Descartes)

(2) One ought not to believe something unless the belief is falsifiable. The criterion says that the belief is irrational if the belief is not falsifiable. It is irrational to believe something if the belief in question is not falsifiable. (Popper)

3. Popper ([1983] 1992, 27): "In fact, I have suggested that what distinguishes the attitude of rationality is simply openness to criticism."

4. Popper ([1992] 2005, 97): "There is no better synonym for 'rational' than 'critical'."

5. W. W. Bartley, III, Popper's student, wrote (1987, 212): "Rather, we locate rationality in criticism. A rationalist is, for us, one who holds all his positions - including standards, goals, decisions, criteria, authorities, and especially his own most fundamental framework or way of life - open to criticism. He withholds nothing from examination and review."

6. I do not believe MacDonald attribution to Descartes is correct either. 


Bartley, W.W. III. 1987. Theories of Rationality. In Evolutionary Epistemology, Rationality, and the Sociology of Knowledge, ed. Gerard Radnitzky and W.W. Bartley, III, 205-214. La Salle, Illinois: Open Court.

MacDonald, Neil B. 2006. Metaphysics and the God of Israel: Systematic Theology of the Old and New Testaments. Grand Rapids, Michigan: Baker Academic.

Popper, Karl R. [1983] 1992. Realism and the Aim of Science: From the Postscript to the Logic of Scientific Discovery. Ed. W.W. Bartley, III. London, England: Routledge.

Popper, Karl R. [1992] 2005. Unended Quest: An Intellectual Autobiography. London, England: Routledge.