David Hume Also Considers the Nature of Reality and Ways in Which What We Perceive May

Hume and Inductive Reasoning

The two primary types of logic discussed by philosophers are deduction and induction. David Hume sees the same two types of thought in opposition and identifies deduction with abstract concepts such as mathematics and types of thinking that achieve a degree of certitude based on generated rules. Induction is described as reasoning from experience, an empirical approach that means that all knowledge is based on prior experience. Such a view links past and future so that any actions taken in the future have their roots in the past. Hume thus considers the nature of reality and ways in which what we perceive may differ from what is real.

To this end, Hume divides human knowledge into two categories, ideas and impressions, both of which are combined as perceptions. The latter term refers to all of the contents of the mind. Hume says impressions are made up of the immediate data of experience, such as sensations, while ideas are the copies or images of impressions in the thinking and reasoning process of the individual.

Impressions are acquired through sensory observation, and ideas are derived from what remains when we recall those impressions. Hume sees all human knowledge as ultimately gained from impressions, or from the immediate sensory data 2 of experience. Hume differentiates between impressions and ideas in terms of how vivid they may be. Impressions include all human sensations and emotions, and these are strong and vivid. Ideas are merely the faint images of human impressions used for thinking and reasoning. Ideas and impressions do not always correspond with one another, and the categories are more complex as Hume then makes a further distinction between simple and complex perceptions in terms of both impressions and ideas.

Hume then develops the idea that impressions come first, and these produce corresponding ideas after a time of reflection. Hume applies this to concepts like morality, which he says are derived from what he terms sentiment. This raises a number of issues concerning whether or not morality derives from reason or sentiment.

Hume finds that the question of morals is "whether we attain the knowledge of them by a chain of argument and induction, or by an immediate feeling and finer internal sense" (Hume 13). This can raise the issue of whether there are truths beyond the immediate cultural reality so that morality would be considered the same for every rational intelligent being, in all societies. On the other hand, morals might be a matter of individual perception, based on individual human experience. Both ideas have been 3 followed by philosophers. For much of human history, the first idea prevailed as morals were believed to be handed down by God and so to be permanent. A later conception viewed morals as changeable depending on the situation involved at the time. In either case, however, the issue begins with perception and then develops the idea of morality from that perception. Hume’s view of meaning thus links perceptions of reality and moral thought directly together and does the same with other areas of human thought and behavior.

Induction is deemed a problem in terms of whether or not inductive reasoning works and has the role Hume says it does. Hume himself has trouble demonstrating the necessity of induction and finds that there is no logical reason why the future should resemble the past, though in his analysis of induction the future must resemble the past if induction is to be taken as true. Hume himself was a skeptic and questioned everything, including his own views on these issues. Skepticism would suggest that the past cannot be taken as a guide for the future, though Hume saw such a view as a form of radical skepticism he did not advocate.

Still, Hume’s conclusion was a challenge to philosophical thought as he concluded “that there is no justification for regarding what has been observed to happen in the past as 4 any sort of reliable guide to the future, subverted the prevailing methodology of observation and experiment on the back of which rode the new mathematical sciences that seemed at the time Hume wrote to have attained an extraordinary degree of success, and have gone on doing so”

(Howson 1).

An argument that answers Hume would be that there is a

“uniformity of nature” such that the past as derived by experience must represent the future because the laws governing that past do not change. Hume would find that this might be true but that it is an assumption that cannot be justified logically. These laws are believed to be permanent because we have never found an exception to them, but this in itself does not mean there is no exception. So long as we accept that there is no exception, of course, the past does serve as a model for the future. Once an exception is found, the rule would no longer apply and could not be taken as a guide for the future.

Another way of viewing the problem is that Hume wanted to link the idea of causation with that of necessary connection. The laws of nature themselves are determined through induction, or repeated observation over time. Such an inductive approach suggests what reality seems to be by observation, but Hume points out that there is no logical 5 justification for assuming that such laws are immutable and always prevail. Stating that induction must be true because the application of the uniformity of the laws of nature is a tautology, given that the laws of nature are themselves derived by induction and so cannot be used to prove that induction is correct. The real meaning of the uniformity of the laws of nature would be that exceptions have not been found, not that they cannot be found. The scientific method is based on the view that induction is true until it is not true, that reality and causation can be determined on the basis of existing knowledge, but that new data may lead to a new conclusion. It is never assumed that no new data is possible, though a strict inductionist would have to assume that this is the case in order to assure that the future could be found in the past. In a broader sense, though, the basic tenet of induction would still hold because the future would have to be a reflection of the past, while the past could be other than we perceive it to be. The limitations on human perception and the degree to which human perception can be fooled is the real problem of induction, for logic can only be applied to what we know and not to what may be true but may also not be known. 6

Following the idea of the tabula rasa of Locke, an idea accepted by Hume, knowledge can only be found in experience as the individual begins as a blank slate and then learns from experience. If those experiences are limited in any way, then the rules derived may be faulty because they are based on limited evidence. It can be assumed that perceptual limitations mean that experience on some level is always short of reality without negating the essential proposition that the future is linked to the past. The real issue is the distance there may be between perception and reality. 7

Works Cited

Howson, Colin. Hume's Problem: Induction and the

Justification of Belief. Oxford: Clarendon Press,

Hume, David. An Enquiry Concerning the Principles of

Morals. Indianapolis: Hackett, 1983.