The Gettier problem: Are you justified in believing what you know to be true?

Knowledge can be divided into three categories: personal, procedural, and propositional. Scientific knowledge falls under the propositional knowledge category; throughout history, philosophers have focused on increasing this type of knowledge. More importantly, philosophers interested in epistemology, which is literally the area of philosophy that studies knowledge, have targeted propositional knowledge.

Propositional knowledge can be understood as declarative knowledge, or “an assertion that something is so.” The French mathematician and polymath Jules Henri Poincaré once said that “Science is facts; just as houses are made of stone, so is science made of facts; piles of stones is not a house, and a collection of facts in not necessarily science.” Science is the assertion that a certain pile of facts represents some truth.

First, some background knowledge on, well, knowledge. The philosopher Plato wrote in Theaetetus about how one comes to know something. He is responsible for giving us our understanding of knowledge, which has been called justified true belief, now known as the JTB theory. This theory follows what is called the Tripartite Analysis of Knowledge, which is written in the form of a necessary and sufficient condition.

The supposition, in which the subject (S) knows a fact [proposition (P)] if and only if (IFF) certain conditions are met, can be written as follows:

(a)  S knows P IFF
(i)  S believes P, and
(ii)  P is true, and
(iii)  S is justified in believing P.

This is the most popular form of the Tripartite Analysis of Knowledge; a few other philosophers valiantly attempted to alter the conditions in the original JTB theory to more fully grasp what it means to truly know something. However, there are still some errors in the conditions laid out in the then-accepted formation of JTB.

In steps Edmund Gettier.

Edmund Gettier was a philosophy professor at the University of Massachusetts, Amherst. While in his postdoctoral Mellon Fellowship, Gettier studied Bertrand Russell’s theories of belief and how these theories affected contemporary thought.

“Science is facts; just as houses are made of stone, so is science made of facts; piles of stones is not a house, and a collection of facts in not necessarily science.”


-- Jules Henri Poincaré

Gettier shook the world of epistemology in 1963 with his seemingly small two-and-a-half-page essay titled Is Justified True Belief Knowledge. The paper was an attempt to address the issues of JTB by adequately “[stating] necessary and sufficient conditions for someone’s knowing a given proposition.”

The crux of Gettier’s argument rests on two key examples, or what he called cases. For the sake of brevity, I will only briefly describe his first case, which is the more popular of the two.

Two men, Smith and Jones, go into a job interview. Smith was told after his interview, by the president of the company nonetheless, that Jones would be the one getting hired. Smith uses this first-person knowledge as evidence for his belief that Jones will get the job, along with the knowledge that he gained in the waiting room when he observed that Jones had ten coins in his pocket. (In this odd scenario, Smith somehow counted the coins to know for certain there were ten.) Smith formed the following justified conclusions:

(b) The man who gets the job will be Jones, and Jones has ten coins in his pocket, so
(c) The man who will get the job has ten coins in his pocket.

BUT, unbeknownst to Smith, it is he himself who will get the job. Additionally, Smith unknowingly has ten coins in his pocket. Therefore, proposition (c) stands and (b) fails. The proposition can then be seen as:

(i) The man who will get the job has ten coins in his pocket,
(ii) Smith believes that the man who will get the job has ten coins in his pocket, and
(iii) Smith in justified in believing that the man who will get the job has ten coins in his pocket.

Where Gettier brilliantly draws a distinction is at the point where Smith does not actually know that (c) is true, because he has no idea how many coins are in his own pocket, but he does in fact know how many coins are in Jones’ pocket, and he believes that Jones will be hired. 

As you can see, although the condition “S knows that P IFF” is true for a proposition (Case 1 with Smith and Jones, for example) it is “at the same time false that the person in question knows that proposition.”

Why does this matter?

Gettier revealed a seemingly innocuous flaw in our understanding of knowledge that seemed to have bypassed every analysis of knowledge up until the late 20^th century – it turns out that this flaw is crucial.

The flaw here is as follows: How can someone have a belief that is true and is supported by evidence but fails to be considered knowledge by the epistemologists. This leads to repercussions in all fields, but in my opinion, science feels these effects the most.

Science is based on this type of knowledge and it is evidence based. Think of evidence in the form of a brain scan to determine some brain abnormality. Science is built on Karl Popper’s Falsification Principle, which states that for something to be scientific it must be testable, and it must be falsifiable. If a claim of knowledge is made in science, and it is a true claim that is “justified”, but those justifications are flawed, those looking at science from the outside could find it hard to believe whatever the claim of knowledge is due to the flawed justification. 

"Lucky Belief occurs when a true claim is made based on flawed justifications, as if one happened to get lucky when making the claim."

-- Jacob Weaver

This creates what Richard Brock calls “Lucky Belief.” Lucky Belief occurs when a true claim is made based on flawed justifications, as if one happened to get lucky when making the claim. An example of this can be seen, in some sense, with the old practices of bloodletting. The practice of bloodletting dates to ancient Egypt, in which Egyptians believed that removing blood from the body was the best way to cure illnesses. They justified this belief based on their witnessing of the hippopotamus secreting red liquid, which they assumed was blood and a way for the hippo to relieve stress.

It turns out that bloodletting has actual health benefits – along with many risks – because removing blood from the body allows for the removal of some toxins, slowing down the progression of some bacterial pathogens, and thus slowing its growth.

Were the Egyptians right in their claim?  I would say they were. Bloodletting was the main treatment for many illnesses, even a broken heart at one point, and it is still used today for illnesses such as hemochromatosis (too much iron in the blood). However, the Egyptians justification for their belief was flawed – the red substance secreted by the hippos is actually an oil with red pigments that acts like sunscreen. This is Lucky Belief.

Because of this need for robust and accurate evidence in science, a void has been created between the philosophically minded thinker and the scientifically minded one. This issue, this chasm, between philosophy and science is most evident in the discussions around consciousness. I believe the scientifically minded thinker must be philosophically trained. Having a philosophical undertone in scientific works, namely the field of neuroscience, may lead to some advances in shortening this divide.

My next article will discuss the neuroscience of consciousness, qualia, what it is like to be a bat, and much more. Until then, I leave you with this question: How do you know that what you believe about something is true?