Originally, fallibilism (from Medieval Latin: fallibilis, "liable to err") is the philosophical principle that propositions concerning empirical knowledge can be accepted even though they cannot be proven with certainty,[1][2] or in short, that no beliefs are certain.[3] The term was coined in the late nineteenth century by the American philosopher Charles Sanders Peirce, as a response to foundationalism.


In contemporary epistemology, mainly three interpretations of fallibilism are being employed, these are global fallibilism, critical fallibilism, and local fallibilism. Global fallibilism implies that no beliefs can be conclusively justified,[4] or in other words, that knowledge does not require certainty.[5] Over time, theorists have narrowed down the scope of fallibilism. Critical fallibilists assert that because empirical knowledge can be revised by further observation, any of the things we take as empirical knowledge might turn out to be false. The claim that all scientific claims are provisional and thus open to revision in light of new evidence is widely taken for granted in the natural sciences.[6] Other theorists may restrict fallibilism to particular areas of human inquiry or domains of knowledge, such as empirical science or morality.[7] Infallible beliefs, they propose, can also include those that can be known a priori (such as logical truths and mathematical truths) and self-knowledge. This view is referred to as local fallibilism.[8]

Global fallibilism differs slightly from epistemological nihilism. Global fallibilists believe that no beliefs are certain (not even when established a priori), while proponents of epistemological nihilism advocate that no beliefs are justified. In order to defend their position, epistemological nihilists will either engage in epochē, a suspension of judgement, or they will resort to acatalepsy, a rejection of all knowledge.[9] However, both epochē and acatalepsy are self-contradictory, namely because both concepts are being used as justification. Acatalepsy is also closely related to the Socratic paradox and prevalent within global skepticism and other branches of skepticism.

Additionally, fallibilism has been employed by American philosopher Willard Van Orman Quine to attack, among other things, the distinction between analytic and synthetic statements.[10] British philosopher Susan Haack, following Quine, has argued that the nature of fallibilism is often misunderstood, because people tend to confuse fallible propositions with fallible agents. She claims that logic is revisable, which means that analyticity does not exist and necessity (or a priority) does not extend to logical truths. She hereby opposes the conviction that propositions in logic are infallible, while agents can be fallible.[11] Critical rationalist Hans Albert argues that it is impossible to prove any truth with certainty, not only in logic, but also in mathematics.

Infinite regress and infinite progress

According to American philosopher Scott F. Aikin, fallibilism cannot properly function in the absence of infinite regress.[12] The term, usually attributed to Pyrrhonist philosopher Agrippa, is argued to be the inevitable outcome of all human inquiry, since every proposition requires justification.[13] Infinite regress, also represented within the regress argument, is closely related to the problem of the criterion and is a constituent of the Münchhausen trilemma. Illustrious examples regarding infinite regress are the cosmological argument, turtles all the way down, and the simulation hypothesis. Many philosophers struggle with the metaphysical implications that come along with infinite regress. For this reason, philosophers have gotten creative in their quest to circumvent it.

Somewhere along the seventeenth century, English philosopher Thomas Hobbes introduced the term "infinite progress". With this term, Hobbes had captured the human proclivity to strive for perfection.[14] Philosophers like Gottfried Wilhelm Leibniz, Christian Wolff, and Immanuel Kant, would elaborate further on the concept. Kant even went on to speculate that immortal species should hypothetically be able to develop their capacities to perfection.[15] This sentiment is still alive today. Infinite progress has been associated with concepts like science, religion, technology, economic growth, consumerism, and economic materialism. All these concepts thrive on the belief that they can carry on endlessly. Infinite progress has become the panacea to turn the vicious circles of infinite regress into virtuous circles. However, vicious circles have not been eliminated from the world; hyperinflation, the poverty trap, and sharecropping for instance still occur.

Already in 350 B.C.E, Greek philosopher Aristotle made a distinction between potential and actual infinities. Based on his discourse, it can be said that actual infinities do not exist, because they are paradoxical. Aristotle deemed it impossible for humans to keep on adding members to finite sets indefinitely. It eventually led him to refute some of Zeno’s paradoxes.[16] Other relevant examples of potential infinities include Galileo’s paradox and the paradox of Hilbert’s Hotel. The notion that infinite regress and infinite progress only manifest themselves potentially, actually gave rise to fallibilism. According to philosophy professor Elizabeth F. Cooke, fallibilism embraces uncertainty, and infinite regress and infinite progress are not unfortunate limitations on human cognition, but rather necessary antecedents for knowledge acquisition. They allow us to live functional and meaningful lives.[17]


Historically, fallibilism is most strongly associated with Charles Sanders Peirce, John Dewey, and other pragmatists, who use it in their attacks on foundationalism (the view that any system of rationally justified beliefs must rest on a set of properly basic beliefs—that is, beliefs that are accepted, and rightly accepted, directly, without any justifying belief whatsoever—but which nevertheless are rationally supported by their connections to perceptual and introspective experiences). However, fallibilist themes are already present in the views of both ancient Greek skeptics, such as Carneades, and modern skeptics, such as David Hume. Most versions of ancient and modern skepticism, excepting Pyrrhonism, depend on claims (e.g., that knowledge requires certainty, or that people cannot know that skeptical hypotheses are false) that fallibilists deny.[18]

A proponent of critical fallibilism is Karl Popper, who builds his theory of knowledge, critical rationalism, on falsifiability, echoing the third maxim inscribed in the forecourt of the Temple of Apollo at Delphi, "surety brings ruin". In The Open Society and Its Enemies, he demonstrates its value (emphasis added):

A particularly impressive example of this is the discovery of heavy water, and of heavy hydrogen (deuterium, first separated by Harold C. Urey in 1931). Prior to this discovery, nothing more certain and more settled could be imagined in the field of chemistry than our knowledge of water (H2O) and of the chemical elements of which it is composed. Water was even used for the 'operational' definition of the gramme, the unit standard of mass of the 'absolute' metric system; it thus formed one of the basic units of experimental physical measurements...

This historical incident is typical; and we may learn from it that we cannot foresee which parts of our scientific knowledge may come to grief one day. Thus the belief in scientific certainty and in the authority of science is just wishful thinking: science is fallible, because science is human.

But the fallibility of our knowledge — or the thesis that all knowledge is guesswork, though some consists of guesses which have been most severely tested — must not be cited in support of scepticism or relativism. From the fact that we can err, and that a criterion of truth which might save us from error does not exist, it does not follow that the choice between theories is arbitrary, or non-rational: that we cannot learn, or get nearer to the truth: that our knowledge cannot grow.

5. Fallibilism and the growth of knowledge

By 'fallibilism' I mean here the view, or the acceptance of the fact, that we may err, and that the quest for certainty (or even the quest for high probability) is a mistaken quest. But this does not imply that the quest for truth is mistaken. On the contrary, the idea of error implies that of truth as the standard of which we may fall short. It implies that, though we may seek for truth, and though we may even find truth (as I believe we do in very many cases), we can never be quite certain that we have found it. There is always a possibility of error; though in the case of some logical and mathematical proofs, this possibility may be considered slight.

But fallibilism need in no way give rise to any sceptical or relativist conclusions. This will become clear if we consider that all the known historical examples of human fallibility — including all the known examples of miscarriage of justice — are examples of the advance of our knowledge. Every discovery of a mistake constitutes a real advance in our knowledge. As Roger Martin du Gard says in Jean Barois, 'it is something if we know where truth is not to be found'.

For example, although the discovery of heavy water showed that we were badly mistaken, this was not only an advance in our knowledge, but it was in its turn connected with other advances, and it produced many further advances. Thus we can learn from our mistakes.

This fundamental insight is, indeed, the basis of all epistemology and methodology; for it gives us a hint how to learn more systematically, how to advance more quickly...

— Karl Popper, The Open Society and Its Enemies, Addenda, I. Facts, Standards, and Truth: A Further Criticism of Relativism[19]


Moral fallibilism is a specific subset of the broader epistemological fallibilism outlined above. In the debate between moral subjectivism and moral objectivism, moral fallibilism holds out a third plausible stance: that objectively true moral standards may exist, but they cannot be reliably or conclusively determined by humans. This avoids the problems associated with the relativism of subjectivism by retaining the idea that morality is not a matter of mere opinion, while offering an account for the conflict between differing objective moralities. Notable proponents of such views are Isaiah Berlin (value pluralism) and Bernard Williams (perspectivism).


Nearly all philosophers today are fallibilists in some sense of the term.[20] Few would claim that knowledge requires absolute certainty, or deny that scientific claims are revisable (though some philosophers recently argue for some version of infallibilist knowledge[21]). But many philosophers would challenge "global" forms of fallibilism, such as the claim that no beliefs are conclusively justified. Historically, many Western philosophers from Plato to Augustine to René Descartes have argued that some human beliefs are infallibly known. Plausible candidates for infallible beliefs include beliefs about logical truths ("Either Jones is a Democrat or Jones is not a Democrat"), beliefs about immediate appearances ("It seems that I see a patch of blue"), and incorrigible beliefs (i.e., beliefs that are true in virtue of being believed, such as Descartes' "I think, therefore I am"). Many others, however, have taken even these types of beliefs to be fallible.[22]

See also


  1. ^ "Fallibilism". Lexico Dictionaries.{{cite web}}: CS1 maint: url-status (link)
  2. ^ Charles Sanders Peirce, "The Scientific Attitude and Fallibilism," in Justus Buchler, ed., Philosophical Writings of Peirce. New York: Dover, 1955, p. 59.
  3. ^ Stephen Hetherington, "Fallibilism," Internet Encyclopedia of Philosophy, http://www.iep.utm.edu/fallibil/
  4. ^ Hetherington, "Fallibilism"; Nikolas Kompridis, Critique and Disclosure. Cambridge: MIT Press, 2006.
  5. ^ Richard Feldman. Epistemology. Upper Saddle River, NJ: Prentice-Hall, 2003, p. 122; Alvin I. Goldman and Matthew McGrath, Epistemology: A Contemporary Introduction. New York: Oxford University Press, 2015, p. 119.
  6. ^ Kuhn, Thomas S. The Structure of Scientific Revolutions. 3rd ed. Chicago, IL: University of Chicago Press, 1996
  7. ^ Hetherington, "Fallibilism", Section 1.
  8. ^ Rauser, Randal (2009). Theology in Search of Foundations. Oxford University Press. doi:10.1093/acprof:oso/9780199214600.001.0001/acprof-9780199214600. ISBN 978-0-19-921460-0. {{cite book}}: |last= has generic name (help)
  9. ^ Popkin, Richard H (2003). The history of scepticism: from Savonarola to Bayle. Oxford; New York: Oxford University Press. ISBN 978-0-19-535539-0. OCLC 65192690.
  10. ^ W. V. O. Quine, "Two Dogmas of Empiricism," http://www.ditext.com/quine/quine.html.
  11. ^ Haack, Philosophy of Logics, pp. 234
  12. ^ Aikin, Scott F. (2014). "Prospects for Moral Epistemic Infinitism". Metaphilosophy. 45 (2): 172–181. doi:10.1111/meta.12071. ISSN 1467-9973.
  13. ^ Annas, J (2000). "Sextus Empiricus: Outlines of Scepticism". Cambridge University Press.{{cite web}}: CS1 maint: url-status (link)
  14. ^ Hobbes, T (1976). "De homine". Medical History. 20 (1): 100–100. doi:10.1017/S0025727300022122. ISSN 2048-8343.
  15. ^ Rorty, A; Schmidt, J, eds. (2009). Kant's Idea for a Universal History with a Cosmopolitan Aim. Cambridge University Press. ISBN 978-0-521-87463-2.
  16. ^ Aristotle. "Physics". classics.mit.edu.{{cite web}}: CS1 maint: url-status (link)
  17. ^ Cooke, E.F. "Peirce's Pragmatic Theory of Inquiry: Fallibilism and Indeterminacy". Notre Dame Philosophical Reviews.{{cite web}}: CS1 maint: url-status (link)
  18. ^ Feldman, Epistemology, pp. 122-28.
  19. ^ Popper, Karl (1961). The Open Society and Its Enemies. p. 701. Retrieved 26 July 2020.
  20. ^ Hetherington, "Fallibilism," Section 1.
  21. ^ E.g. Moon, Andrew (2012). "Warrant does entail truth". Synthese. 184 (3): 287–297. doi:10.1007/s11229-010-9815-2. S2CID 9851726.; Dutant, Julien (2016). "How to be an infallibilist" (PDF). Philosophical Issues. 26: 148–171. doi:10.1111/phis.12085.; and Benton, Matthew (2018). "Knowledge, hope, and fallibilism". Synthese. 198: 1673–1689. doi:10.1007/s11229-018-1794-8. S2CID 46955518..
  22. ^ Haack, "Philosophy of Logics", Chapter 12.

Further reading

  • Charles S. Peirce: Selected Writings, ed. by Philip P. Wiener (Dover, 1980)
  • Charles S. Peirce and the Philosophy of Science, ed. by Edward C. Moore (Alabama, 1993)
  • Traktat über kritische Vernunft, Hans Albert (Tübingen: Mohr, 1968. 5th ed. 1991)
  • Richard Feldman, Epistemology. Upper Saddle River, NJ: Prentice-Hall, 2003, Chap. 6.
  • Susan Haack, Philosophy of Logics. Cambridge University Press, 1978, Chap. 12.
  • "Fallibilism". Internet Encyclopedia of Philosophy.