Hello! Welcome to our final lecture in this module on theories of justification.
Introduction
Over the past few lessons, we've surveyed a fascinating landscape of epistemological theories. We started with internalist views like foundationalism and coherentism, which locate justification within our web of beliefs and experiences. We then moved to an externalist view, process reliabilism, which places justification in the objective reliability of our belief-forming processes. Most recently, we explored virtue epistemology, which shifts the focus to the intellectual character of the person forming the belief.
Today, we will step back to consolidate our understanding of the single most significant fault line in contemporary epistemology: the divide between internalism and externalism. Our goal is to contrast how these two families of theories determine whether a belief is justified. We will crystallize what is truly at stake in this debate and see why different philosophers, starting from different intuitions, arrive at such profoundly different conclusions about the nature of knowledge.
The Great Divide: Is Justification an Inside Job or an Outside Connection?
At its heart, the debate between internalism and externalism boils down to a single question: What kinds of facts determine whether a belief is justified?
- Internalism argues that justification is determined solely by factors internal to a person's mind. These are things you can access through reflection alone: your other beliefs, your reasons, your memories, your sensory experiences.
- Externalism argues that justification depends on factors external to a person's mind—factors you might have no reflective access to at all. This "external factor" is typically some kind of objective connection to the world, like a reliable process or a causal link to a fact.
To get a firm grasp on this fundamental distinction and its implications, let's watch an excellent video that lays out the core positions and introduces some of the key thought experiments that drive the debate.
Internalism and Externalism - Epistemology Video 13
This video by Victor Gijsbers provides a clear and methodical introduction to internalism and externalism, using helpful examples to illustrate their core commitments.
Please watch from the beginning to 16:22. As you watch, focus on: The definition of internalism (justification is internal and accessible). The different ways 'internal' can be understood (accessibility, mental states, personal perspective). The core idea of externalism, using reliabilism as the main example (the method is reliable, but you don't need to know it's reliable).
What "Justification" Means to Each Camp
As the video highlighted, internalists and externalists don't just disagree on the location of justifiers; they often have fundamentally different ideas about the purpose of justification itself.
The Internalist View: Epistemic Responsibility
For an internalist, justification is closely tied to the idea of epistemic duty or responsibility. You are justified in holding a belief if you have done your intellectual duty by believing in accordance with the evidence and reasons available to you. It’s about being a responsible thinker from your own perspective.
Think back to Descartes. His entire project was to believe only what he could see clearly and distinctly to be true. He was trying to fulfill his duty as a rational being. This is the spirit of internalism. If you've done everything you can from your own point of view to ensure your belief is true, then you are justified—even if you turn out to be wrong because of factors beyond your control.
The Externalist View: A Reliable Link to Truth
For an externalist, justification is not primarily about duty or responsibility. It's about having an objective, truth-conducive connection to the world. A belief is justified if it's produced by a process that reliably gets you to the truth, regardless of whether you are aware of that process or have any reasons you can articulate.
Some externalists go even further. As discussed in the resource "Epistemic Externalism" by Daniel Bonevac, they might argue that the traditional concept of "justification" is largely irrelevant for knowledge. What matters is the belief, its truth, and the reliable link between them. Alvin Goldman's early Causal Theory of Knowledge, for example, analyzed knowledge as true belief caused by the relevant fact, dropping the justification condition entirely.
Theory of Knowledge: Analyzing Knowledge #3 (Causal and ...
To see how some externalist theories sideline the traditional notion of justification, please read this brief excerpt on Alvin Goldman's Causal Theory.
Read the first five paragraphs of the transcript, starting from 'my name is Jennifer Nagel...' and ending with '...as long as your belief was caused in the right way with a causal chain going back to the fact itself.' Notice the explicit statement that Goldman drops the justification condition.
This is a crucial point of contrast:
- Internalism: Justification is an essential, non-negotiable condition for knowledge, and it's about having accessible reasons.
- Externalism: The connection to truth is what's essential. "Justification" is either redefined to mean "a reliable truth-connection" or is seen as secondary to that connection.
Battle of Intuitions: Testing the Theories
Philosophers test these competing views using thought experiments designed to pull our intuitions in one direction or the other. Here are the most famous ones.
Case 1: The Clairvoyant (Norman's Case)
Imagine a person named Norman who, without his knowledge, is a perfectly reliable clairvoyant. One day, he spontaneously forms the belief, "The President is in New York City." He has no evidence for this belief; it just popped into his head. As it happens, the belief is true, and his clairvoyance is working perfectly.
- Internalist Verdict: Unjustified. Norman is being epistemically irresponsible. From his perspective, he has no reason to hold this belief. It's a mere hunch.
- Externalist (Reliabilist) Verdict: Justified. His belief was formed by a 100% reliable process (clairvoyance). The objective connection to the truth is perfect.
This case is a major challenge for externalism, as most people share the intuition that Norman does not know, precisely because he lacks any reasons for his belief.
Case 2: The New Evil Demon Problem
Imagine you have a twin who is a brain in a vat (BIV), living in a simulated world created by an evil demon. Every mental experience your BIV twin has is identical to yours. When you see a tree, your twin has an identical experience of seeing a tree. But for you, the belief "there is a tree" is true, while for your twin, it's false.
- Internalist Verdict: You and your twin are equally justified. Both of you are forming beliefs in a perfectly rational and responsible way based on the evidence of your senses. The fact that the twin's evidence is misleading is beyond their control.
- Externalist Verdict: You are justified, but your twin is not. Your perceptual processes are reliable (they connect you to a real tree), while your twin's are completely unreliable (they are fed by a demon).
This case is a major challenge for externalism. It seems deeply unfair to say the BIV twin is unjustified when, from their perspective, they are being a model of epistemic virtue.
Case 3: Everyday Knowledge (Children, Animals, and Grandmas)
Externalism strikes back with cases from everyday life.
Think about a young child who knows her name, a dog that knows its owner is home, or a grandmother who knows her grandchildren's faces but couldn't articulate an argument for her belief if challenged.
- Internalist Verdict: Problematic. To be justified, these individuals must have reasons that are accessible to them. It's unclear if a dog or a very young child has "accessible reasons" in the way a philosopher means. This makes it hard for internalists to grant them knowledge.
- Externalist Verdict: No problem. The child knows her name via the reliable process of testimony. The dog knows its owner is home via reliable perception (hearing the key in the door). The grandmother knows the faces via a reliable perceptual-memory system. The objective connection is what matters, not their ability to philosophize about it.
This is where externalism seems to align better with our common-sense attributions of knowledge.
Test your understanding!
Consider the case of the "chicken-sexer" — a person who is expertly trained to determine the sex of newborn chicks with very high accuracy, but they cannot explain how they do it. They say, "I just look at the chick and I just know."
Which theory, internalism or externalism, would have an easier time saying the chicken-sexer has justified beliefs? Why?
Show answer
Externalism would have a much easier time.
For an externalist (specifically, a reliabilist), the chicken-sexer's belief-forming process is demonstrably reliable. That's all that's required for the belief to be justified.
An internalist would struggle. The chicken-sexer cannot access or articulate any reasons for their belief. From their internal perspective, it's just a hunch, similar to the clairvoyant Norman. Since they can't fulfill their "epistemic duty" by basing their belief on good reasons, the internalist would be forced to say their belief is unjustified.
Summary: A Tale of Two Theories
The table below summarizes the fundamental contrasts we've discussed.
| Feature | Internalism | Externalism |
|---|---|---|
| Location of Justifiers | Inside the mind (beliefs, experiences, reasons) | Outside the mind (reliability, causation, environment) |
| Key Requirement | Access to reasons; epistemic responsibility | Objective connection to truth |
| Agent's Perspective | Central and all-important | Often irrelevant |
| Verdict on Evil Demon Twin | Justified (epistemically blameless) | Unjustified (unreliable process) |
| Verdict on Clairvoyant | Unjustified (no reasons, a mere hunch) | Justified (reliable process) |
| Verdict on Animal/Child | Problematic (lacks accessible reasons) | Unproblematic (has reliable processes) |
Conclusion
Today, we've pulled back the curtain on the central conflict in the theory of justification. The choice between internalism and externalism hinges on which set of intuitions you find more powerful.
Key Takeaways:
- Internalism holds that justification is determined by factors accessible to the agent, tying it to epistemic duty and responsibility. Its strength lies in cases like the Clairvoyant and the Evil Demon, where perspective seems to matter most.
- Externalism holds that justification is determined by an objective, truth-conducive link to the world, like a reliable process. Its strength lies in accounting for the knowledge of unsophisticated thinkers like children and animals.
- The disagreement is fundamental: it concerns the very purpose of justification and what kind of creatures we are as knowers—are we primarily responsible reasoners or reliable information-gatherers?
Preview of the Next Lesson:
So far, both internalists and externalists have been working on the same project: explaining how we can have knowledge. But what if this entire project is based on a false assumption? In our next module, we will confront the ultimate challenge: skepticism. We will start by outlining the structure of classic skeptical arguments, like the brain-in-a-vat scenario, which argue that knowledge is not just difficult, but perhaps impossible to attain.