Justification makes a belief more likely to be true by providing reasons in favor of the truth of the belief. A natural way to think of justification is that it provides logical support. Logic is the study of reasoning, so logical support is strong reasoning. If I am reasoning correctly, I am justified in believing that my dog is a mammal because all dogs are mammals. And I am justified in believing that = if I did the derivation correctly. But what if I used a calculator to derive the result? Must I also have reasons for believing the calculator is reliable before being justified in believing the answer? Or can the mere fact that calculators are reliable justify my belief in the answer? These questions get at an important distinction between the possible sources of justification—whether justification is internal or external to the mind of the believer. Internalism and Externalism Theories of justification can be divided into two different types: internal and external. Internalism is the view that justification for belief is determined solely by factors internal to a subject’s mind. The initial appeal of internalism is obvious. A person’s beliefs are internal to them, and the process by which they form beliefs is also an internal mental process. If you discover that someone engaged in wishful thinking when they came to the belief that the weather would be nice today, even if it turns out to be true, you can determine that they did not know that it would be nice today. You will believe they did not have that knowledge because they had no reasons or evidence on which to base their belief. When you make this determination, you reference that person’s mental state (the lack of reasons). But what if a person had good reasons when they formed a belief but cannot currently recall what those reasons were? For example, I believe that Aristotle wrote about unicorns, although I cannot remember my reasons for believing this. I assume I learned it from a scholarly text (perhaps from reading Aristotle himself), which is a reliable source. Assuming I did gain the belief from a reliable source, am I still justified given that I cannot now recall what that source was? Internalists contend that a subject must have cognitive access to the reasons for belief in order to have justification. To be justified, the subject must be able to immediately or upon careful reflection recall their reasons. Hence, according to internalism, I am not justified in believing that Aristotle wrote about unicorns. On the other hand, an externalist would say my belief about Aristotle is justified because of the facts about where I got the belief. Externalism is the view that at least some part of justification can rely on factors that are not internal or accessible to the mind of the believer. If I once had good reasons, then I am still justified, even if I cannot now cite those reasons. Externalist theories about justification usually focus on the sources of justification, which include not only inference but also testimony and perception. The fact that a source is reliable is what matters. To return to the calculator example, the mere fact that a calculator is reliable can function as justification for forming beliefs based on its outputs. An Example of Internalism: Ruling Out Relevant Alternatives Recall that the “no defeaters” theory of knowledge requires that there exist no evidence that, if known by the subject, would undermine their justification. The evidence is not known by the subject, which makes the evidence external. The fourth condition could instead be an internal condition. Rather than require that there exist no evidence, one could say that S needs to rule out any relevant alternatives to their belief. The “no relevant alternatives” theory adds to the traditional account of knowledge the requirement that a person rule out any competing hypotheses for their belief. Ruling out refers to a subject’s conscious internal mental state, which makes this condition internal in nature. Like the “no defeaters” condition, the “no relevant alternatives” condition is meant to solve the Gettier problem. It does so by broadening the understanding of justification so that justification requires ruling out relevant alternatives. However, it still doesn’t solve the Gettier problem. Returning to the barn example, the possibility that there are barn facades is not a relevant alternative to the belief that one is looking at a barn. Unless one is in Hollywood, one would not think that facades are a distinct possibility. An Example of Externalism: Causal Theories Externalists hold that a subject need not have access to why their true beliefs are justified. But some theorists, such as American philosopher Alvin Goldman (b. 1938), argue that the justification condition in the account of knowledge should be replaced with a more substantial and thorough condition that effectively explains what justification is. Goldman argues that beliefs are justified if they are produced by reliable belief-forming processes (Goldman 1979). Importantly, it is the process that confers justification, not one’s ability to recount that process. Goldman’s account of knowledge is that a true belief is the result of a reliable belief-forming process. Goldman’s theory is called historical reliabilism—historical because the view focuses on the past processes that led to a belief, and reliabilism because, according to the theory, processes that reliably produce true beliefs confer justification on those beliefs. Reliable belief-forming processes include perception, memory, strong or valid reasoning, and introspection. These processes are functional operations whose outputs are beliefs and other cognitive states. For example, reasoning is an operation that takes as input prior beliefs and hypotheses and outputs new beliefs, and memory is a process that “takes as input beliefs or experiences at an earlier time and generates as output beliefs at a later time” (Goldman 1979, 12). Usually, memory is reliable in the sense that it is more likely to produce true beliefs than false ones. Because Goldman’s approach is externalist, the justification-conferring process need not be cognitively accessible to the believer. His view has also been called causal because he focuses on the causes of belief. If a belief is caused in the right way (by a reliable belief-forming processes), then it is justified. One virtue of this approach is that it accounts for the intuition that someone could have a justified belief without being able to cite all the reasons for holding that belief. However, this view is not without fault. The original impetus behind revising Plato’s traditional JTB analysis was to solve the Gettier problem, and Goldman’s account cannot do this. Consider again Henry and the barn. Henry looks at a real barn and forms the belief that it is a barn. Henry’s belief that he is looking at a barn is caused by a reliable belief-forming process (perception), so according to Goldman’s account, Henry does have knowledge. Yet many philosophers think that Henry doesn’t have knowledge given the lucky nature of his belief.