As far as the problem of induction is concerned, its essence boils down to the support of inductive methods, which are inherent in scientific inference and imply, according to Hume, that “instances, of which we have had no experience resemble those, of which we have had experience”. It is difficult to justify these methods for two reasons. Firstly, the principle is relative and deduction cannot be applied to prove it (since deduction is applicable only to essential truths). Secondly, induction cannot justify the principle as well since it would require to assume what is to be argued, i.e. that the principle has been accurate in the past (stanford.edu).
To put it simply, Hume claims that people can hold justified opinion only of the things that they have observed. That is, one cannot display even the slightest degree of confidence of things, which he or she has not observed (Lange 1). Proceeding from this statement, Hume, in An Enquiry Concerning Human Understanding, mentions that humans’ reasonable beliefs are to be “limited to the narrow sphere of our memory and senses”. For science, Hume’s argument means the rejection of its epistemic achievements, which, in turn, undermines the scientific authority and leads to skepticism. The philosopher argues that all attempts to justify induction will fail and even tries to exclude the possibility of justifying it.
Therefore, Hume emphasizes that inductive arguments lack any rational background and cannot back up their conclusions. Further, common sense and science are incompatible with justified inductive predictions. Those philosophers who tried to prove the opposite failed; others attempted describing science as a notion that excludes the presence of confidence in humans’ predictions. Karl Popper, for instance, has claimed that, despite the fact that science disproves general hypotheses as it is logically incongruous with humans’ observations, science always denies the predictive precision of a general hypothesis (Lange 2). Science makes people guess what they have not observed, and humans cannot but hazard guesses even though they cannot find a reason for imparting any degree of confidence to it:
I think that we shall have to get accustomed to the idea that we must not look upon science as a ‘body of knowledge,’ but rather as a system of hypotheses; that is to say, a system of guesses or anticipations which in principle cannot be justified, but with which we work as long as they stand up to tests, and of which we are never justified in saying that we know that they are ‘true’ or ‘more or less certain’ or even ‘probable’.
As it becomes obvious from the excerpt, Popper rejects Hume’s conclusion that science turns out to be unable to produce knowledge of the world. Like Hume, Popper believes that no confirmed scientific hypotheses offer proofs of their truth. Nevertheless, a hypothesis can be refuted even if there is only one observation that differs from a hypothesis. Consequently, it can be reasonably concluded that although empirical enquiry does not prove the truth of hypotheses inductively, deduction can be applied to prove the falsity of a hypothesis.
Further, Popper replaces induction with the method of refutation and conjecture. According to the philosopher, the process that leads scientists to definite hypotheses can be evaluated neither rationally nor logically. That is why scientific hypotheses are nothing but mere suggestions (conjectures). No evidence can confirm hypotheses inductively so that one has substantial reasons for believing his or her hypotheses to be true. Evidence that corresponds to a hypothesis will never provide it with inductive justification. If a hypothesis corresponds to all the evidence completely, it can be claimed that it is a “corroborated” hypothesis. This statement, however, is equal to another one claiming that a hypothesis has sustained one’s attempts at confutation. Therefore, only contrary evidence is capable of a decisive refutation of hypotheses.
Apart from claiming that scientific methods are purely deductive and that induction is nothing but a subject to psychological relevance, Popper is to be praised for the solution to the so-called demarkation problem. In his opinion, to distinguish between science and “pseudo-science,” one should refer to the notion of falsifiability, not verifiability. To say that a statement is falsifiable is to say that under some probable observable conditions, one may judge the statement to be false (bellevuecollege.edu). Thus, scientific claims are those that can be falsified, not verified. From this standpoint, scientific theories should never be regarded as undeniable truths since they are always open to falsification, revision, and criticism. Likewise, the primary objective of science is not to corroborate hypotheses.
A different view on induction was offered by Wesley Salmon, who rejected Hume’s arguments as well as Popper’s claims about “refutation and conjectures.” Salmon’s approach to the problem is known as pragmatic. Examining his pragmatic justification, it is essential to grasp that the outcome of inductive reasoning is rather a postulate than an assertion. Salmon also argues that, although inductive principles would not necessarily be validated, there exists a chance that they are to be vindicated. Salmon’s principle of vindication runs as follows: if any rule posits the accurate probability, the inductive rule is also applicable and it is, consequently, the simplest and the most successful in this respect.
All things considered, the problem of induction challenges the possibility of scientific cognition of the world. Scientific reasoning cannot be claimed to be purely inductive. Scientific laws cannot emanate from experience only since they are exceptionally complex in essence.