Philosophy of Science, Problem of Induction - Essay Example

PROBLEM OF INDUCTION If one is right claiming that our scientific principles are, at best, inductive generalisations that are derived from sets of particular scientific judgments, then those scientific principles, at best, cannot be known to be universal and at worst, are entirely without merit. Scientists need to identify some of the risks involved in using induction and specifically the risks involved in using induction reasoning to come up with scientific principles as well as specific scientific judgments. Practically, induction throws up at least three general causes for concern: (1) There are a number of skeptical concerns associated with using induction. However, even with those skeptical concerns cast aside (2) Strong inductive arguments never guarantee their results and often create predictions that turn out to be false. And finally, insofar, as it has any legitimacy to begin with, (3) Inductive judgments/reasoning can be constructed which suggest that the exception will continue to pop up future proposed universal principles, just as it has for past ones. This paper discusses the problem of induction and how it impacts current knowledge and approach to science. This discussion revolves primarily around works of David Hume and Karl Popper due to the former theorising on induction more than any other philosopher and the latter revealing inapplicability of induction for science and scientific method. INTRODUCTION Alan Musgrave (2004) in his critique of induction problem introduces Hume's argument as the basis for understanding the dilemma. Musgrave distinguishes Hume's three points, namely: (1) we reason, and must reason, inductively; (2) inductive reasoning is logically invalid and (3) to reason in a logically invalid way is irrational. Thus, the problem of induction is a problem confronted by scientists and philosophers concerned with science, but more specifically it is a problem for scientific method. Furthermore, it is a problem for the practice of science, for scientific endeavor, and it is a problem for the procedures of science. From the critical perspective, as science is or ought to be, it faces and must solve the problem of induction. HUME AND THE PROBLEM OF INDUCTION David Hume created a philosophical system to explain his understanding of human nature. He provided a solid non-metaphysical explanation of the nature of human thought to use as a foundation to his philosophy. As an empiricist, Hume believed our knowledge is of the phenomenal world and is gained through experience. The following passage addresses not only his opinion regarding metaphysics, but his basic belief regarding the significance of ideas and impressions: All ideas, especially abstract ones, are naturally faint and obscure: the mind has but a slender hold of them: they are apt to be confounded with other resembling ideas; and when we have often employed any term, though without a distinct meaning, we are apt to imagine it as a determinate idea annexed to it. On the contrary, all impressions, that is, all sensations, either outward or inward, are strong and vivid; the limits between them are more exactly determined: nor is it easy to fall into any error or mistake with regard to them (Hume, 1985, p.49). Hume built a unique system of knowledge. Creating complex ideas by comparing or combining simple ideas is the province of understanding, which includes imagination as well as the intellect. Everything we believe comes from experience, either as a simple idea derived from direct experience or as a complex of related ideas abstracted from experience. Human understanding comes from applying the intellect and imagination to ideas in order to form beliefs about the phenomenal world. Hume claimed there are only three types of connection between ideas: resemblance, contiguity in time and space, and cause and effect (Hume, 1999, p.101). Therefore, beliefs are gained by applying the intellect and imagination to ideas to abstract what they have in common, including location and relations of cause and effect. Those beliefs become knowledge if we have certainty. Hume claimed the truth of any claim that can be posed is established by determining whether the claim is a matter of fact or a relation of ideas and if the claim cannot be established as either of these then Hume advises its truth cannot be established at all (Norton, 1993, p.96). This is often referred to as "Hume's Fork." "Cause and effect" is one of the three connections between ideas that Hume identifies. The other two connections are "resemblance" and "contiguity in time and space." Hume focuses his attention on cause and effect because it is the only connection between ideas that could move us beyond immediate experience. One example Hume uses to illustrate this point regards observation of the game of billiards. When we observe one billiard ball strike a second billiard ball and the second ball move away from the point of impact in a specific manner, we would be inclined to say the first ball caused the second ball to move as it did via the observed impact. From the critical perspective, we cannot know whether the movement of ball one caused the subsequent movement of ball two because our only experience was observation of the actual movement of the balls. We cannot observe cause or effect. Hume advises we come to have the concept of cause and effect from a habit of mind. When we observe a sequence of events occurring in the same order at every observation, with no instance of them occurring in any other order or one occurring without the other, we come to have an expectation of seeing the two events so connected. This expectation amounts to the following inductive reasoning: if the first ball strikes the second ball like it has in the past, then the second ball will move in the specific manner as in the past. The problem, for David Hume and anyone wanting to use inductive reasoning, is that there is no guarantee that the future will resemble the past. Unlike mathematical truths, which operate under a closed system, truths about matters of fact operate in relation to the flux of events in nature. Since the phenomenal world is in constant change, there is nothing that guarantees the future will resemble the past (i.e., there is no entailment between past or current experience and future experience). From the scientific perspective, in addition to the a priori truths such as those found in mathematics, we can only know that which we can demonstrate. For instance, we cannot demonstrate the future because it has not yet occurred. In addition, cause and effect is not a relation of ideas, as there is no necessity linking the effect to the cause. In induction, scientists identify causal relations between objects and events and then project the probability of their occurrence in future. Practically, there are always other possible explanations of what scientists deem to be cause or effect; therefore, there is no foundation of certainty regarding the causal connection. SCIENCE AND SCIENTIFIC METHOD Musgrave (2004) indicates that Karl Popper's reasoning allows us to more beyond Hume's problem of induction (p.31). As he continues to explains, "Induction or inductive logic is a myth, after all, because we do not need" (Musgrave, 2004, p.31). In order to understand Musgrave's position, we can start first with Popper's position on science and scientific method as a prelude to the discussion of induction problematics. It is not by accident that Popper's principal work on the philosophy of science is titled The Logic of Scientific Discovery because according to Popper, it is the business of philosophy to determine which methodology, which set of methodological rules, is best suited to scientific endeavour. Methodological rules are "the rules of the game of empirical science," says Popper (p.53), they reflect, and in a way comprise, the logic of scientific discovery. The philosopher, however, is not a scientist. It is not his job to determine what actually the methodological rules of science are, or how science is actually practiced by active scientists. Because not only it is possible that ""the whole of science'' might err," it is not possible to answer the most "controversial" epistemological questions by adopting an empirical, or "naturalistic," approach to methodology (Popper, 1959, p.29, p.53). That is not to say that methodology is not at all descriptive; an acceptable methodology of science must reflect the essentials of scientific activity. It is just that these essentials cannot be gleaned by a purely empirical investigation. How, scientists decide upon the methodological rules According to Popper, the most important thing to understand about methodological rules is that they are "conventions - rules conventionally adopted, either explicitly or implicitly, by people" (Popper, 1959, p.53). Thus, those who "discover" a methodology naturalistically cannot claim a superiority for their rules, because even their rules are conventions, and they may not be the best conventions in view of the aims of science. Secondly, it is of no concern to methodology how scientists conceive of their theories. That question is perhaps the concern of empirical psychology, but it has no bearing on the logic or scientific knowledge, which is concerned with the testability and justification of, and logical relations between, scientific statements (Popper, 1959, p.31). In fact, it is because "the psychology of knowledge" has been confused with "the logic of knowledge" that the "belief in inductive logic" is so prevalent (Popper, 1959, p.30). From this perspective, methodological rules constitute conventions; however, it does not give the answer on how they are formulated and how one determines whether or not they are acceptable. Karl Popper provides an implicit answer to this question indicating that methodological rules should be judged by how well they fulfill their intended purpose. The intended purpose of Popper's methodological rules is to ensure the applicability of a "supreme rule" (Popper, 1959, p.54), namely, Popper's "demarcation criterion." This criterion, which is intended to demarcate science from metaphysics, stipulates that a theory is to be regarded as scientific, and admitted into the domain of science, if and only if it is falsifiable Like the methodological rules based upon it, the demarcation criterion is to be understood as a "proposal for no agreement or convention:" As to the suitability of any such convention opinions may differ; and a reasonable discussion of these questions is only possible between parties having some purpose in common. The choice of that purpose must, of course, be ultimately a matter of decision, going beyond rational argument (Popper, 1959, p.37). Thus, Popper's methodology, and any other for that matter, can only be evaluated in relation to a purpose or goal. Since his methodology is a methodology of science, the relevant goal must be the aim or aims of science. The acceptability of a methodology depends upon how well it helps science attain its aims. SCIENCE AND ITS OBJECTIVES Karl Popper vividly articulates that the principal objective of the science "is or ought to be, the search for truth" (Popper, 1972, p.319). Although Popper never makes an explicit statement about the objectives of science in his Logic of Scientific Discovery, this is evidence of Popper's view of the scientific purpose. For instance, he says that "the striving for knowledge and the search for truth are still the strongest motives of scientific discovery," and that "the man of science" is characterised by "his persistent and recklessly, critical quest for truth" (Popper, 1959, p.278). This position is reiterated in The Open Society and Its Enemies, where Popper says that "in science we do our best to find the truth" (Popper, 1966, p.263), and more specifically, that in the theoretical sciences "we wish to know whether universal laws or hypotheses are true" (Popper, 1966, p.263). And in The Aim of Science (1972) Popper states clearly that science aims to explain known phenomena by means of true explicants. In addition, since 1962 Popper has repeatedly said that the aim of science is progress, and in particular, increased verisimilitude. In his Truth, Rationality, and the Growth of Scientific Knowledge, Popper says that "truth is a 'regulative' idea, and "that the task of science is the search for truth" (Popper, 1963, p.229). E. J. Lowe in his essay points out that Popper "sees the task of science not as one of establishing truths but rather as one of eliminating falsehoods" (Lowe, 1987, p.327). Popper however adds, admittedly, that truth is not the only aim, because we also want "interesting truth" (i.e., solutions to our problems, answers to our questions), but his point, obviously, is that both truth and increased verisimilitude are the objectives of science As regards the question which aim is primary, Popper does not explicitly say, but when he discusses his solution to the problem of induction, he states it in relation to truth, and then adds on his new views on verisimilitude (Popper, 1963, p.235). This should suffice to show that truth is still the primary aim or science, and that Popper's solution to the problem of induction should be judged in relation to this aim. PROBLEM OF INDUCTION: POPPER'S PERSPECTIVE One notices that Popper's choice of demarcation criterion is determined by the aim of science, and that the aim of science is truth. What is still unknown is how Popper arrives at precisely the methodology he proposes. What is missing is the role that logic plays in selecting the demarcation criterion, and in formulating a methodology. For Popper, logic is decisive, because it alone determines what is possible, and what is not possible. In particular, it is logic that tells us that what we ideally want, namely certainty, cannot be procured. The problem arises in the following way. If truth is the aim of science, then the scientist is specifically looking for true theories. Furthermore, if Popper is right about the irrelevance of theory conception to theory evaluation, then we should design our methodology to help us evaluate theories which have already been proposed. Now, the most obvious, and certainly ideal, methodology would allow us to ascertain the truth values of theories, for if we could ascertain any theory's truth value, we could retain all of the true theories, and reject all of the false ones. Such a methodology would not, of course, guarantee that we would end up with any true theories, since we might never hypothesise correctly about the world. But it would guarantee the truth of any retained theory, which is to say, it would guarantee that we would not retain any false theories. In the absence of a methodology that could produce true theories, this is surely the next best thing. The problem with this ideal possibility is that, on the assumption that we cannot directly intuit laws of nature, logic rules it out. In The Logic of Scientific Discovery, Popper does not discuss the possibility of directly intuiting laws of nature, but it is clear that he assumes that such intuition is impossible, because if we could directly know the truth and falsity of scientific theories, there would be no point in stressing the invalidity of inductive inferences, nor would it make sense to advocate a fallibilistic, falsificationist methodology. However, given this assumption, logic rules out the further possibility that we can establish the truth of scientific theories indirectly, by means of our experiences. Popper calls this "the problem of induction," but actually, it is only the first of two distinct formulations of the problem that he presents in The Logic of Scientific Discovery. The first formulation is stated as follows. The question whether inductive inferences are justified, or under what conditions, is known as the problem of induction.The problem of induction may also be formulated as the question of the validity or the truth of universal statements which are based on experience, such as the hypotheses and theoretical systems, of the empirical sciences. For many people believe that the truth of these universal statements is 'known by experience'; yet it is clear that an account of an experience - of an observation or the result of an experiment - can in the first place be only a singular statement and not a universal one (Popper, 1959, p.28). From the critical perspective, there are two important questions contained in the foregoing quotations: (1) Can inductive inferences be logically justified (2) Can natural laws (i.e. universal statements about the world) be known to be true Popper indicates that these two questions are roughly equivalent. What he means, of course, is that, given the aforementioned assumption, they are basically the same question. Thus, it is more accurate to say that Question #1 is logically prior to Question #2, since an answer to the latter question depends upon an answer to the former. Popper does not solve his first formulation of the problem of induction, because his answer to Question #1 is NO. Inductive inferences, he claims, cannot be justified. In arguing for this claim, Popper begins by pointing out that, in and of themselves, inductive inferences are not logically valid: It is far from obvious, from the logical point of view, that we are justified in inferring universal statements from singular ones, no matter how numerous; for any conclusion drawn in this way may always turn out to be false: no matter how many instances of white swans we may have observed, this does not justify the conclusion that all swans are white (Popper, 1959, p.27). For Popper, this is equivalent to saying that inductive inferences are not naturally, logically justified. That is to say, by themselves they are not logically justified, simply because they are not logically valid. What, however, about the possibility of "justifying inductive inferences" by somehow putting them "into a logically acceptable form"(Popper,1959, p.28). Popper allows for this possibility, but says that to justify inductive inferences one would first have to establish a "principle of induction." The first thing to note about a principle of induction, he says, is that it must be a synthetic statement, for if it were an analytic statement, inductive inferences would be "tautological transformations" on a par with deductive inferences, which clearly they are not. Secondly, since the principle of induction must, in addition to being synthetic, also, be a universal statement (i.e., it must refer to all inductive inferences), it can itself only be established as true by means of inductive inferences. But to justify these inductive inferences, we must invoke a principle of induction "of a higher order," and so on, ad infinitum. Thus, the attempt to justify induction by a justified principle of induction leads to an infinite regress, a fact that was first recognised by Hume. Therefore, from this perspective, there are no such things as a priori valid (true) synthetic statements. Popper's case against justifying inductive inferences by means of a principle of induction is best summed up by his conclusion in Two Faces of Common Sense: "induction is invalid because it leads either to an infinite regress or to apriorism" (Popper, 1972, p.86). From the critical perspective, there are still questions regarding the problem of induction that have not been answered yet. Popper calls the problem of induction a "problem," but it is not entirely clear why it is a problem. What Popper means, of course, is not that Question #1 is a problem (it is, after all, only a question), but that a negative answer to it creates a problem, and in particular, that it creates a serious problem for science. What he means is that it seems to create a problem, for science, and that this apparent difficulty is the problem of induction. Thus, it is Popper's second formulation of the problem of induction that reveals its problematic character: The proposed criterion of demarcation also leads us to a solution of Hume's problem of induction - of the problem of the validity of natural laws. The root of this problem is the apparent contradiction between what may be called "the fundamental thesis of empiricism" - the thesis that experience alone can decide upon the truth or falsity of scientific statements - and Hume's realization of the inadmissibility of inductive arguments (Popper, 1959, p.42). All that follows from the conjunction of the invalidity of inductive arguments and the fundamental thesis of empiricism is that experience cannot decide upon the truth of some scientific statements, namely universal statements (i.e., theories). This, by itself, is still not a problem. What we need is some other statement, a statement that makes this fact problematic. Popper provides this missing statement in the continuation of the previously quoted passage, where he says that "this contradiction arises only if it is assumed that all empirical scientific statements must be 'conclusively decidable, i.e. that their verification and their falsification must both in principle be possible" (Popper, 1959, p.42). From this perspective, we are finally in the position to state the problem of induction, which is (1) The truth-values of all scientific statements must be conclusively decidable. (2) It is impossible to determine whether some scientific statements (i.e., universal statements) are true. REFERENCES Lowe E.J. (1987). What is 'the problem of induction' Philosophy, 62, pp. 325-340 Musgrave A. (2004). How Popper [Might Have] Solved the Problem of Induction. Philosophy, 79, pp.19-31 Hume, D. (1985). A Treatise of Human Nature. London, England: Penguin Books Hume, D. (1999). An Enquiry concerning Human Understanding. Oxford, New York: Oxford University Press. Norton, D. (1993). The Cambridge Companion to Hume. New York: Cambridge University Press. Popper, K. (1959). The Logic of Scientific Discovery. London: Hutchinson & Co. Ltd Popper, K. (1963). Conjectures and Refutations: The Growth of Scientific Knowledge. New York: Harper & Row Publishers Popper, K. (1966). The Open Society and Its Enemies. The High Tide of Prophecy: Hegel, Marx and Aftermath, Volume I, II. London: Routledge & Kegan Paul Popper, K. (1972). Objective Knowledge: An Evolutionary Approach. Oxford: The Clarendon Press Read More