Posted on

David Hume’s Problem of Induction in Debate and on TV

Portrait of David Hume by Allan Ramsay

Will the future be like the past?

All of life seems to be connected. Cause and effect. If I touch a hot stove today and get burned I can safely assume that I’ll get burned if I do it again. And that goes for different kinds of stoves, open fires, barbecues, fireworks, etc. This kind of thinking—from specific instances to generalizations—is inductive.

[Tweet “Our lives are full of inductive thinking from the pedantic to the prodigious.”]

So what’s the problem? Inductive thinking seems to be pretty useful so why all the hubbub?

Blame Davi Hume. It all started when he wondered how we could be justified in assuming that the connections we perceive between events, cause and effect, actually exist. We certainly feel like we see the connection between events. That’s not Hume’s point. He acknowledges that we all do that. He’s asking a much more basic question.

How do we justify our expectation that the future will be like the past?

This is the problem of induction.

The Problem of Induction on TV

An exchange between Jonah and Amy on NBC’s show Superstore is an example of how we use the inductive principle in everyday life. It’s a short clip.

David Hume the Trouble Maker

David Hume (Scottish philosopher and historian) clearly stated the problem on induction in An Enquiry Concerning Human Understanding:

To recapitulate, therefore, the reasonings of this section: Every idea is copied from some preceding impression or sentiment; and where we cannot find any impression, we may be certain that there is no idea. In all single instances of the operation of bodies or minds, there is nothing that produces any impression, nor consequently can suggest any idea, of power or necessary connexion. But when many uniform instances appear, and the same object is always followed by the same event; we then begin to entertain the notion of cause and connexion. We then feel a new sentiment or impression, to wit, a customary connexion in the thought or imagination between one object and its usual attendant; and this sentiment is the original of that idea which we seek for. For as this idea arises from a number of similar instances, and not from any single instance; it must arise from that circumstance, in which the number of instances differ from every individual instance. But this customary connexion or transition of the imagination is the only circumstance, in which they differ. In every other particular they are alike. The first instance which we saw of motion, communicated by the shock of two billiard-balls (to return to this obvious illustration) is exactly similar to any instance that may, at present, occur to us; except only, that we could not, at first, infer one event from the other; which we are enabled to do at present, after so long a course of uniform experience.[1]

Portrait of David Hume by Allan Ramsay
Portrait of David Hume by Allan Ramsay

Dr. Peter Atkins Tries to Answer Hume

An audience member asked Dr. Peter Atkins what his solution is to the problem of induction. Atkins’ response make it clear he had no idea what he was talking about. There’s a transcript below the video player.

Questioner: Dr. Atkins, a philosopher from Scotland, David Hume, pointed out that we as human beings don’t really have a rational basis for believing in the uniformity of nature—that the future will be like the past. Dr. Atkins, as a Christian, I can believe that the future will be like the past, or that nature is uniform, because I believe that God created the universe and this universe reflects the uniformity which God has imposed upon through his governing.

I’d like to ask, in the atheistic worldview the presupposition that there is no God and that all we have is mater in motion what is your basis for believing that the future will be like the past?

Dr. Atkins: Well I don’t believe that the future will be like the past because I believe in continuing evolution. I believe that the universe is expanding and therefore the universe will in the future will not be like the universe in the past. I also believe but at a deeper level—if I could respond there—on the cogency and the continuity of the physical law. Physical laws are commentaries on the behavior of mater and of radiation and whatever else you want to include. And so I see, because matter and radiation don’t change their character, physical laws do not change their character. I see the universe evolving into the future, changing as it goes, but the physical laws that underlying the universe will not change.

Dr. Bahnsen Cross-Examines Dr. Stein on the Problem of Induction

You can read a full transcript of the debate here.

Dr. Bahnsen: Okay, Dr. Stein you made reference to David Hume and his rejection of miracles, have you also read David Hume and his discussion of induction or more popularly the uniformity of nature?

Dr. Stein: A long time ago. I can’t recall the… exactly what he says. I have read David Hume.

Dr. Bahnsen: Okay, were you convinced a long time ago that you had an answer to Hume’s skepticism about induction?

Dr. Stein: I can’t answer that question honestly. I don’t remember what…this was at least fifteen years ago that I read this.

Dr. Bahnsen: Scientific laws were, the validity of scientific laws were undermined by Hume when he contended that we have no rational basis for expecting the future to be like the past. Or, if you will, to be…for there to be types of events so that one event happening can be understood as a type of event so where it’s seen happening somewhere else the same consequence can be expected from similar causation. Hume said we had no rational basis for that…

David Agopian: Excuse me Dr. Bahnsen can we have a question please for Dr. Stein.

Dr. Bahnsen: Yea I’m trying to setup the question.

David Agopian: Okay. Okay.

Dr. Bahnsen: Hume suggested that there was no rational basis for expecting the future to be like the past in which case science is based simply on convention or if you will habits of thought. Do you agree with Hume?

Dr. Stein: Not on this issue I don’t.

Dr. Bahnsen: Do you now have an answer for Hume?

Dr. Stein: I think he was wrong about that one thing. But he was also right about a lot of other things. Nobody’s perfect.

Dr. Bahnsen: What is the basis for the uniformity of nature?

Dr. Stein: I went through this but I’d be glad to reiterate it.

Dr. Bahnsen: Okay.

Dr. Stein: The uniformity of nature comes from the fact that matter has certain properties which it regularly exhibits. It’s part of the nature of matter. Electrons, oppositely charged things attract, the same charges repel. There are certain valances that can fill up the shell of an atom and that’s as far as it can combine.

Dr. Bahnsen: Do all electrons repel each other?

Dr. Stein: If they’re within a certain distance of each other, yes.

Dr. Bahnsen: Have you tested all electrons?

Dr. Stein: All electrons that have ever been tested repel each other. I have not tested all.

Dr. Bahnsen: Have you read all the tests on electrons?

Dr. Stein: Me personally or can I go on the witness of experts?

Dr. Bahnsen: Have you read all of the witnesses about electrons?

Dr. Stein: All it takes is one witness to say “no” and it would be on the front pages of every physics journal and there are none so therefore I would say yes in effect by default.

Dr. Bahnsen: Well, physicists have their presuppositions by which they exclude contrary evidence, too. But in other words you haven’t experienced all electrons but you would generalize that all electrons under certain conditions repeal each other?

Dr. Stein: Just statistically, on the basis of past observation.

Dr. Bahnsen: And we don’t know that it’s going to be that way ten minutes after this debate then?

Dr. Stein: No, but we see no evidence that it’s switched around either?

Paul Manata with Dan Barker on the Problem of Induction

Dan’s Opening Statement

In Dan Barker’s opening statement we responded to some of the comments Paul Manata made in his opening statement (although such a response should have been reserved for Dan’s rebuttal). Here’s what Dan said:

Logic and morality, the inductive, the problem, the so called problem of induction, these are false problems. These are phony problems.

You don’t have to define or give a source for these things any more than you have to give a source for digestion. Digestion is one of the ways that a stomach functions. First you have to have a stomach and the stomach functions. And one of the functions of the stomach is to digest food.

Digestion is not a thing out there that has to be justified for its existence. Digestion is just one of the things that a stomach does. Logic and reason and induction are not things that have to be justified or sources given for them. They are one, or some of the ways that an organ called the brain functions properly.

Even the simplest animals, at a simple level, at a primitive level are using logic and reason. As data comes into their brains they process that data and they make decisions based upon, you know, they’re not even conscious of it. We more conscious animals will sometimes formalize the logic and pretend like it’s a big subject, and it is, you know to formalize the steps of how you would go from A to B to C, and to specify that A is not not-A, you know, the excluded middle, all those things which is fun to do.

But logic and induction and reasoning itself don’t have to be justified. They don’t even have to be presupposed. They are not things that you presuppose. You don’t presuppose digestion. Digestion is the way the stomach works. So Paul is asking a non-question when he demands that we atheists somehow have to justify our presuppositions. In my book, I did not say that logic is a presupposition that atheists make. What I did say was that when we’re gonna solve an argument using logic we have to first examine the underlying assumptions.

Paul Cross-Examines Dan

Paul cross-examined Dan about the problem of induction. Here’s how that exchange went:

Manata: Are you familiar with the problem of induction?

Barker: Yes I am.

Manata: What is your secular answer for how you resolve the problem of induction?

Barker: By saying that the conclusions that we derive from induction are tentative, weak conclusions. They are much weaker than deductive conclusions. The concussions that we draw from induction are useful but not necessarily true. You can have an inductive conclusions that is false and in fact science has repeatedly come up with inductive conclusions that have turned out to be false. So I do not pretend that a conclusion based on induction is a solid fact.

Manata: Right but how do you justify the problem of induction. You said you’re familiar with the problem of induction. How do you justify… what’s your secular answer… was it, that it works?

Barker: Well, I just told you. It works enough. It doesn’t work perfectly. It is useful. It works, you know. That’s how we know that snakes don’t talk. We’ve never seen a snake that doesn’t [sic] talk. But if we do find a snake that talks. If we do find one in reality, then that tentative law by induction would have to go. We would have to adjust our thinking. Induction is not a very, I mean it’s useful but it’s not a very important logical principle.

Paul’s Rebuttal of Dan

When it was time for Paul’s rebuttal he addressed Dan’s solution for the problem of induction by pointing out three errors:

Lastly, induction. There are also many problems with Mr. Barker’s attempted resolution of the problem of induction. First, it’s a pragmatic justification and not an epistemic one. He said it just works. Secondly, the question is what justifies you proceeding upon the expectation that the future will resemble the past? To say it’s worked in the past and since it’s worked in the past I can assume, with probability, that it’ll work in the future, is to beg the question. Lastly, even Mr. Barker himself thanks that his secular answer doesn’t cut it. In Losing Faith in Faith on page 61 Mr. Barker relays a story by Mr. Bertrand Russell. Basically the story says that in the town of Changsha, China during a lunar eclipse blind men would beat gongs to frighten the heavenly dog who was attempting to swallow the moon. This practice has worked for thousands of years. The point is that just because something works does not mean it’s rational. Dan Barker’s basic justification for the problem of induction is basically beating a gong.

Solutions to the Problem of Induction

Think you can do better than Peter Atkins, Gordon Stein, or Dan Barker? You may want to think again.

The Cambridge Dictionary of Philosophy ends their section on the problem of induction this way:

None of the many suggestions is widely accepted as correct.[2]

This isn’t very encouraging. Do you know who’s tried to come up with a solution to the problem of induction? The list reads like an A & C Black list of philosophers: Karl Popper, Immanuel Kant, Rudolf Carnap, Hans Reichenbach, and Nelson Goodman.

You can read a detailed discussion of the various proposed solutions here[3] and here[4].

Suffice to say, Christians cite the unchanging nature of God as the reason why we can reliably expect the future to be like the past. To those who say this is a copout please feel free to present your own solution. If you don’t have a solution to offer please remain in your seat until the house lights come up.

Non-Christians have proposed many solutions none of which has the weight of the philosophical world behind it.


  1. Hume, David. “An Enquiry Concerning Human Understanding.” DavidHume.org. Accessed December 09, 2015. http://www.davidhume.org/texts/ehu.html.  ↩
  2. Audi, Robert “Problem of Induction.” In The Cambridge Dictionary of Philosophy, 745–46. 2nd ed. New York: Cambridge University Press, 1995.  ↩
  3. Anderson, James N. “Secular Responses to the Problem of Induction.” Analogical Thoughts. Accessed December 09, 2015. http://www.proginosko.com/docs/induction.html.  ↩
  4. Vickers, John. “The Problem of Induction.” Stanford University. November 15, 2006. Accessed December 09, 2015. http://plato.stanford.edu/entries/induction-problem/.  ↩
Posted on

A Primer on Knowledge? Rationalism vs Empiricism

The Consituents of Knowledge

Humans are knowing creatures. Our mental capabilities are vital to our existence and full of amazing possibilities. Our ability to expand our knowledge spurs science, culture, and religion forward. But how do we know what we know? Maybe we should back up a little. What is knowledge? How do we grow what we know? Can we justify what we know to others? Knowledge—what seems to be a basic feature of everyday life—is a complex subject.

What Is Epistemology?

All these inquiries fall under the philosophical branch of study called epistemology. The word epistemology is an English word derived from two Greek words:

  • Episteme (knowledge or understanding)
  • Logos (the study of)

In short, epistemology is the study of knowledge.[1] Philosophers know it as the “study of the theory of knowledge.” We’ll look at a brief historical overview of the philosophical category of epistemology. Our special focus will be the differences between rationalism and empiricism.

What is Knowledge?

Knowledge is “justified true belief.” It’s been the accepted definition for centuries and it’s the one I’ll be using.[2] Defining one’s terms is easy to neglect, but it’s integral to the philosophical process. More ink has been spilled over definitions than you’d imagine. So let’s take care of this important matter. Knowledge is “justified true belief.” This definition has three parts:

  • Belief – You must believe something in order for to have knowledge. You cannot know something is you don’t believe it.
  • Truth – The thing you believe must correspond to reality. You cannot know something that is false.
  • Justification – You need a reason for your belief. This is why guessing the number of M&Ms in a carnival game (it’s 527 by the way) by chance is called “luck.” You cannot “luck” into knowledge.

The Consituents of Knowledge

You need all three to have knowledge. If you only have two out of three you get one of the following:

  • Belief + Truth = Something you believe, that’s also true, but for which you lack any justification. Some might call this blind faith.
  • Belief + Justification = Something you believe but are wrong about.
  • Truth + Justification = Something you should believe but don’t.

3 Kinds of Knowledge

Philosophers have categorized knowledge into three different and unique groups:[3]

Acquaintance Knowledge (Who)

The knowledge of a person through being in some sort of relationship to them. Sometime called intimate knowledge.

Competence Knowledge (How)

The knowledge of a skill or ability. For example, knowing how to play an instrument or a sport. It’s a knowledge gained through repetition and the development of muscle memory.

Propositional Knowledge (What)

The knowledge of facts or propositions gained through study or observation.

Putting It All Together

What’s it like to have one kind of knowledge but not another about a topic? Imagine I knew every fact (proposition) about you mother: height, favorite movie, age, etc. My knowledge would still be qualitatively different from yours. You know her (acquaintance knowledge). I just know about her. The same goes for competence knowledge. You can tell me all the facts about how to play the trumpet, but I won’t be able to play it well without practice and repetition.

The Acquisition and Justification of Propositional Knowledge

The only kind of knowledge debated by philosophers is propositional knowledge. The two major schools of thought that have been duking it out for centuries are:

  • Rationalism (Represented by Plato)
  • Empiricism (Represented by Aristotle)

The other minor schools of thought are just variations of these two. I consider myself a rationalist and utterly detest empiricism. Nonetheless I’ll try to give you an accurate account of both.

Plato and the Rationalist School

Plato believed that humans participated in two spheres of existence:

  • The world of the forms (pure being)
  • The world of particular things (becoming)

The world of the forms is an unchanging immaterial world of pure being. The world of particular things is the material, constantly changing world we’re all familiar with. Plato got these ideas from two philosophers before him, Heraclitus and Parmenides.[4]
For Heraclitus, ultimate reality is in a state of flux; it’s always changing or becoming. He said that you can never step in the same river twice. If you remove your foot from the river and then put it back, all the molecules have moved and it is, in a sense, a different river.[5]

Parmenides, on the other hand, believed that all of reality is pure being. He realized that there are such things as universal, unchanging principles. For example, one plus one equals two.

Plato saw the elements of truth in both perspectives. Instead of picking one over the other, he synthesized them into his doctrine of the two worlds. Plato agreed with Parmenides that there are unchanging principles. Plato calls these unchanging principles the “forms.” Plato relegated the forms to another world because he agreed with Heraclitus that the world we experience is always changing. Thus Plato divides the universe into two categories:

  • Forms (essences)
  • Particulars (individual examples of forms)

Plato taught that every particular thing represents an essence. For example, if you draw a square your drawing would be a particular square and not the essential or perfect square. Your particular square is representing the idea (form) of the perfect square.

Plato applied this dualism to mankind saying that the human being is composed of body and soul. The body is participating in the world of becoming by getting older and changing in appearance. The soul is participating in the world of the forms through immortality and reason. Plato did this because he noticed that humans are capable of interacting with the forms through reason. He attributed this ability to the reality of innate ideas.[6]

Innate Ideas

Innate ideas are a form of knowledge that the mind contains prior to experience and birth. For Plato, innate knowledge is knowledge of the forms. Plato explained the existence of innate ideas with that of the preexistence of the soul. The only way that one could have knowledge of the forms at birth is if the person’s soul existed in the world of the forms prior to birth.[7] For Plato knowledge in this life is not a process of acquisition but of remembrance.

The World of Particulars Is Structured on the World of the Forms

Plato contends that the world of particular things is structured off off the world of the forms. This means that the mind is capable of understanding things about the external world (the world outside one’s own mind) because it’s conscious of the structure that the world it’s founded upon. This is essentially what it means to be rationalist; it is to believe that the world and the mind share the same structure. This is what makes knowledge possible. For the rationalist, reason is both a reliable and primary guide for grounding knowledge.

Aristotle and the Empiricist School

Aristotle was Plato’s student. He knew all about Plato’s doctrine of the two worlds, but rejected it. Although he believed in universals (forms), he denied the preexistence of the soul as being necessary to explain how we know about them. Aristotle said we become conscious of universals the other way around. Rather than starting with innate ideas we start with particulars and work our way up. This is because Aristotle believed that universals or the forms are not innate knowledge.[8]
Aristotle said we’re all born as blank slates. We acquire knowledge through our experience of particulars. We then universalize these experiences and apply them to new experiences.[9]
Consider the idea of similarity. Things that are similar share certain characteristics. Remember the game “Which of these does not belong?” You won by picking item doesn’t share the characteristic the others do. Care to play? Which of the following does not belong:

  • Bat
  • Penguin
  • Crow
  • Sparrow

If you answered “Bat” congratulations! Bats are mammals the rest are birds. Bird-ness is what all the members of the list above share (their similarity) except for the bat. We learn what bird-ness is by experiencing particular birds. This is what it means to be an empiricist; we gain knowledge through experience. For an empiricist, experience is the grounding principle of knowledge.

And the Winner Is…

In conclusion, as tempting as empiricism may appear, it has significant problems. How can the idea of similarity even get off the ground if we didn’t have some notion of it to begin with? This goes for the idea of equality, dissimilarity, and sameness as well. If it’s true that we’re born with no innate knowledge how could we come to any conclusions at all? We couldn’t. Empiricism destroys knowledge. We’d be a bundle of perceived particulars we couldn’t do anything with. We’d be like the beasts driven by instinct. Or we might be like a tree having life but no discernible consciousness. If empiricism destroys our foundation for knowledge then it is demonstrably inferior to rationalism.

Rationalism Works

Furthermore, rationalism works. We can apply universal principles to the external world (the world outside our own minds) successfully. Engineers do this every day. They draw their reason on paper. When followed, reason produces stable buildings. This implies that reality has a structure complementary to the human mind. But how could this be? Was Plato right? Is there a world of forms that serves as the foundation for the world of particular things?

Rationalism, Plato’s Forms, and God’s Aseity

Since we just finished beating up empiricism you may be tempted to say “yes.”. Not so fast. There’s one more qualification we need to make. In the Christian worldview God is the only entity which has the characteristic of aseity. Aseity is complete independence.[10] The forms are not completely independent, but rather find their origin in the mind of God which St. Augustine pointed out.[11]

Because we’re created in God’s image we have these principles implanted in our consciousness. This makes the whole knowing enterprise possible. It also explains why rationalism works. The external world is intelligible because a supremely intelligent God created it.

Christian rationalism is superior to empiricism because:

  • It has the most explanatory power.
  • It does not share the weaknesses of empiricism.
  • It’s faithful to the Bible.
  • It works in the real world.

So there you have it, an overview of the differences between rationalism and empiricism.

Christian Apologetics by Douglas Groothuis


  1. Lawhead, William F. The Philosophical Journey: An Interactive Approach. Mountain View, CA: Mayfield Pub., 2000. 52. Print. ↩
  2. Lawhead, William F. The Philosophical Journey: An Interactive Approach. Mountain View, CA: Mayfield Pub., 2000. 53. Print. ↩
  3. Lawhead, William F. The Philosophical Journey: An Interactive Approach. Mountain View, CA: Mayfield Pub., 2000. 52. Print. ↩
  4. Nash, Ronald H. “History of Philosophy and Christian Thought: Early Greek Philosophers.” Apple (audio blog), November 9, 2010. https://itunes.apple.com/us/podcast/early-greek-philosophers/id403537295?i=88863458&mt=2. ↩
  5. Nash, Ronald H. “History of Philosophy and Christian Thought: Early Greek Philosophers.” Apple (audio blog), November 9, 2010. https://itunes.apple.com/us/podcast/early-greek-philosophers/id403537295?i=88863458&mt=2. ↩
  6. Nash, Ronald H. “History of Philosophy and Christian Thought: The Essence of Plato’s Philosophy.” Apple (audio blog) https://itunes.apple.com/us/podcast/essence-platos-philosophy/id403537295?i=88863473&mt=2 ↩
  7. Botton, Alain De, Benjamin Jowett, and M. J. Knight. The Essential Plato. New York: Quality Paperback Book Club, 1999. 616-17. ↩
  8. Nash, Ronald H. “History of Philosophy and Christian Thought: Aristotle and Dualism.” Apple (audio blog) https://itunes.apple.com/us/podcast/aristotle-and-dualism/id403537295?i=88863462&mt=2 ↩
  9. Lawhead, William F. The Philosophical Journey: An Interactive Approach. Mountain View, CA: Mayfield Pub., 2000. 91. Print. ↩
  10. Robert Audi ed., The Cambridge Dictionary of Philosophy. 2nd ed. Cambridge: Cambridge University Press, 1999. 240. ↩
  11. Nash, Ronald H. “History of Philosophy and Christian Thought: Augustine” Apple (audio blog) https://itunes.apple.com/us/podcast/augustine-01/id403537295?i=88863441&mt=2 ↩