How Reasonable is David Hume’s Skepticism about Induction?

 In Building Knowledge

Some philosophers, notably David Hume, have argued that one cannot gain knowledge through inductive reasoning that they didn’t already know from plain observation. Hume rightly points out that we can only directly know states of affairs in our experience and that when we see several things happen that seem to be correlated, we think we know the cause. Hume says that, for example, one may see the sun come up every day, and from this to try to reason that the sun indeed comes up every day, but he says the only thing anyone can know is that the sun has come up every day so far, not that it is a law of nature that the sun comes up every day. Hume argues that we actually have no knowledge of the factors that caused the sun to come up before and hence we cannot know for certain what will happen in the future. Hume says that there is no way of being justified in a conclusion about the cause of actions because we only actually perceive the objects and never causes or laws of nature. Those opposed to inductive reasoning say that when we see successive events where one event appears to cause another, the only thing we actually know is that one event happened and that another event followed, and that no amount of logical reasoning can justifiably lead one to conclude that the earlier event caused the proceeding event to occur.

Arguments against the possibility of gaining knowledge from inductive reasoning are self-defeating in a similar way as those in favor of extreme skepticism, solipsism, and absolute idealism. This is because those who go with a similar line of reasoning as Hume would say that we cannot know laws of nature, but they are still assuming that we can know about some objects and some events, as isolated points of knowledge. It is a part of this line of reasoning that we can know certain isolated points of knowledge, as a general rule. The implication is that this rule is itself a fact that must be a law of nature (or perhaps derived from laws of nature) that the speaker must have come to know somehow. And how else could Hume, or anyone else, know about this other than from observing the world and using inductive reasoning? Also, anyone who denies inductive reasoning leads to genuine knowledge also assumes that people can hear them or read what they say, which are facts that they also must have come to know from induction. A similar problem with Hume’s argument is that any statement that can be approximately paraphrased as “Inductive arguments never give guarantees for how things are” is self-contradictory in a way similar to other constrain-skeptical arguments including transcendental idealism. This is because, even if one assumes that this is true, it is also true that one could only know this fact through the use of inductive reasoning.

Indeed, Hume himself makes many statements in the form of a law of nature, for example “When a child has felt the sensation of pain from touching the flame of a candle, he will be careful not to put his hand near any candle; but will expect a similar effect from a cause which is similar in its sensible qualities and appearance.” In this statement, Hume appears to be saying, among other things, that the laws of nature determine that children who come in contact with fire will experience pain. How could Hume have come to know this other than through inductive reasoning?

The only reasonable conclusion that one can come to from Hume’s line of reasoning is that one might or might not be able to gain certain knowledge from induction, but it is difficult to see how certainty could be possible, which would be an example of doubt-skepticism. We don’t have evidence for any method of induction that could produce a certain conclusion and so it makes sense to not believe that there is any such method, but it also does not make sense to think that one can disprove this possibility altogether.

There are several reasons why skepticism about inductive reasoning is irrational and unworkable. Perhaps the biggest problem with Hume’s argument is that he argued that one can never even be justified to accept a conclusion from inductive reasoning. It is impossible for anyone to truly believe this and to live as if it were true. We all act as if causes and effects are real and we all acknowledge lawlike orderliness in our world. Also, science would be largely impossible within this strict assumption, since science so often involves searching for causes and effects and laws of nature. Additionally, if this were assumed, one would never have any rational basis to go with a tested hypothesis over an untested one. While it makes sense to doubt that utter certainty could be possible from induction, this does not mean that knowledge cannot be gained from induction because justified conclusions do not always have to be utterly certain.

Anyone looking for the truth should be able to easily conclude that they can, perhaps with much effort, come to know at least some laws of nature through inductive reasoning. From this it should be accepted as truth that we are, in fact, perceiving causes and effects (albeit quite indirectly) along with the objects that we perceive.

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Photo by Letícia Pelissari on Unsplash

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