Problem of Induction

The problem of induction is a philosophical problem in epistemology, which questions whether or not inductive reasoning is a source of knowledge. The problem is most often brought up when discussing the scientific method — for instance, how can repeated observations of an apparently predictable occurence produce certainty about future events? How is it that we can be sure that the future will resemble the past? How can one make universal claims by examining particular events or objects?

Induction problems in early Pyrrhonism

The problem of induction was known in the ancient world. The Pyrrhonian skeptics, most noticably viewed the problem as one with central importance. Carneades, one follower of Pyrrhonism, famously states, “nothing can be known, not even this”. For the Pyrrhonian, doubt is universal and absolute — there seems to be no justifiable reason for forming any certain belief.

Enlightenment formalization by Hume

Scottish empiricist David Hume famously brings attention to the problem in the eighteenth century, after René Descartes had supposedly used reason to demonstrate the existence of God, and provide a foundation for the sciences.

In his A Treatise of Human Nature, Part III, §6, Hume describes the problem. He considers causality as an example of our use of induction:

Thus not only our reason fails us in the discovery of the ultimate connexion of causes and effects, but even after experience has informed us of their constant conjunction, it is impossible for us to satisfy ourselves by our reason, why we should extend that experience beyond those particular instances, which have fallen under our observation. We suppose, but are never able to prove, that there must be a resemblance betwixt those objects, of which we have had experience, and those which lie beyond the reach of our discovery.

Science through deduction, according to Popper

Philosopher Karl Popper, on the other hand, has argued that science, when conducted properly, does not rely on induction in order to discover truth, but rather on deduction. According to Popper, experiential data is recorded and then applied to reason, in order to deductively obtain new information. This information is used to construct theories of science, which are then tested by obtaining new empiricial evidence. In cases where the empirical result contradicts the theory, then the theory is modified to accomodate the new information, until it has demonstrable predictive power, and is a logical conclusion of the collected information.

Popper’s view has been challenged, however, since the supposedly empirical data that is used to conduct logic usually comes in the form of universal claims, which themselves have been determined via induction.