How Do We Know What We Know?

1. Facts vs. Opinions

Some things you believe are facts, such as your age, your height, and how much money you have in your pocket. Others are opinions, such as your favorite flavor of ice cream, the TV shows you enjoy watching, and whether you believe in extraterrestrials.

How do you separate the two? We generally consider factual claims to be things that can be true or false, or having truth value, while opinions don’t have truth value.

EXAMPLE

“Mint chocolate chip is the best ice cream,” cannot be judged true or false. “There is mint chocolate chip ice cream in the freezer,” is either true or not true, and has truth value.

However, some statements propose what a person believes to be the facts. These are opinions in the sense that they are not yet known to be true or false. But unlike opinions about the best flavor of ice cream, these may eventually be revealed as true or false. These statements have truth value, but at the time their truth is unknown.

EXAMPLE

“The butler committed this murder,” is an opinion, but more facts may be revealed that show it to be true or false. The statement has truth value, we just don’t yet know if it is true or false.

To engage in critical thinking, we must adopt an understanding of “opinion” to sometimes mean “a best guess about the truth, based on the evidence,” and not a statement of preference. We must also understand that while some opinions may not be proven true or false (at least not yet), opinions can be evaluated. Opinions can be found “good” (or convincing) or “bad” (not convincing). In some cases, opinions may be described as “likely” or “unlikely,” if they are predictions about future events. The basis for deciding whether such an opinion is good or bad is evidence, other facts that support the claim, and logical interpretation of those facts. This is often (but not always) called a reasoned opinion to distinguish it from matters of preference and taste.

EXAMPLE

“The butler committed this murder,” will not be enough to convince a jury that the butler should be imprisoned. The prosecuting attorney will have to provide facts that support this claim, like the presence of the butler’s fingerprints on the murder weapon, a motive, and an opportunity.

This also means our own opinions can be challenged. To state “I have a right to my opinion,” and consider the matter settled is the opposite of critical thinking.

EXAMPLE

A juror who argues, “I think the butler did it. That’s my opinion,” and refusing to discuss it further is doing a disservice to the other jurors, and to the butler, who deserves to have his case considered carefully.

Becoming a strong critical thinker means evaluating other reasoned opinions based on merits instead of dismissing as “just an opinion.”

EXAMPLE

The same juror might be told that the butler has a solid alibi, spotted my multiple witnesses at a restaurant at the time the murder took place. Saying, “well, you have your opinion, and I have mine,” does not address this evidence or incorporate new information into his worldview. Besides being a disservice to the defendant and to the process, it shows poor critical thinking.

terms to know

Truth Value

A statement that is either true or false.

Reasoned Opinion

A “best guess” as to the truth of something based on evidence and logic.

2. Ways of Knowing

2a. Experience

We now know that some opinions are statement about what a person believes to be true, and these should be based on facts. But how do we know what’s factual? This is a broad and complex topic called epistemology, or the study of knowing. Epistemology is one of the biggest realms of philosophy and impacts many other academic disciplines. We will now consider this tough question.

quote

"“Who are you going to believe, me or your own eyes?” -Chicolini (Chico Marx) in Duck Soup"

—

The first way we know anything is through lived experience. You know that grass is damp in the morning, or that snow is cold, or that honey is sweet, because you have direct experience of those things.

You can even say that these statements are facts, not opinions – that the grass is wet for everyone who walks on it, that snow is cold for everyone who touches it, and that honey is sweet for everyone who tastes it. You can even go further and say that the grass is wet even if nobody walks on it, that snow will have a temperature below freezing even if nobody touches it, and that honey has C6H12O6,, more commonly known as “sugar,” even if nobody tastes it.

So, while direct experience leads us to formulate facts, the facts (by definition) are true even if we do not experience them. However, direct experience isn’t a perfect way to determine facts. We are all subject to perceptual selectivity, meaning that we pay attention to some experiences more than others. Sometimes this is due to the one experience being extraordinary in some way, but it might also be shaped by our interests and culture. Our perceptions are also influenced by what we want to be true.

EXAMPLE

Alice is riding her bicycle home and is nearly hit by a car. When she arrives at home, she can recall that car and its driver perfectly. She cannot recall a single other car or driver she saw.

EXAMPLE

Allen works in security for a large department store, focused on catching shoplifters. At the end of each shift, he can recall customers who were wearing oversized coats despite warm outside temperatures, carrying bags from other stores, or otherwise suspicious as potential shoplifters. He cannot recall anyone else because he was not paying attention to them.

EXAMPLE

Michael and Alice are watching an American football game. After Alice’s favorite team scores a touchdown, the referee throws a flag, meaning the team committed a penalty and the touchdown doesn’t count. Alice says the penalty didn’t occur and the ref is blind. Michael, who’s rooting for the other team, says the penalty was clear. Even though they are watching the same replay and have the same perceptions, they come to different conclusions about what they just saw because they want different things to be true.

As we learned in the last tutorial, an important part of critical thinking is metacognition, and that includes knowing your own perceptual limitations and biases. In the process of using experience to determine facts, it is thus important to know that your perception is selective, and the facts you think you know may be incomplete or distorted. So how do you figure out what really happened? We will discuss that question next.

terms to know

Epistemology

The study of knowledge, and how we know what we know.

Perceptual Selectivity

The cognitive trait of paying attention to some experiences more than others.

2b. Corroboration

One way we can verify our perceived facts is through corroboration, or gathering additional evidence. One way we do this is by talking to others who witnessed the event, or by asking experts to review the evidence we’ve gathered and give their own opinion. Consensus is agreement on what is true based on these many different perceptions. However, consensus is vulnerable to its own errors, such as groupthink, when one person drops their own point of view to go along with the group.

EXAMPLE

Brian sees a car crash and feels that the driver of the red car was speeding. After talking to other witnesses, who all say it was going at a normal speed, he modifies his account of the event.

Corroboration might also be made through physical evidence, or anything that can be measured, photographed, or held and examined. While this is in some ways superior to perceptions or even consensus, physical evidence by itself is also limited.

EXAMPLE

Investigators review the physical evidence at the scene of the accident and determine that indeed the red car was speeding, which they can tell from the length of the skid marks it left on the road where the accident occurred. However, they do not know why it was speeding.

terms to know

Corroboration

Gathering additional information to support a recollection or theory.

Consensus

A general or unanimous agreement as to what is true.

Groupthink

The habit of dismissing personal thoughts or experiences to go along with the group.

2c. Research and Testing

Another way of determining the facts is through research and testing. The difference between investigation and research is the presence of a research question. Investigation is poring over the evidence and trying to figure out what happened. Research is guided by a specific question the researcher is trying to answer.

EXAMPLE

The investigators at the car crash have gathered evidence like broken glass and skid marks to reconstruct what happened. They build a theory about the exact turn of events. One runs computer simulations of the crash to see if the outcomes are what they observed.

Research is connected to testing, or various ways of staging experiments to see if theories are correct, whether it is seeing whether a particular chemical reaction occurs under certain circumstances or whether a group of patients receiving a new medication fare better than a group receiving the traditional medication for the same condition.

Testing can also be done informally, by non-experts, to test their theories.

EXAMPLE

Michael is trying to change some behaviors in his children at bedtime, and starts to experiment with bedtime routines and different bedtimes to see what gets the best results and to identify the “triggers” for challenging behavior.

Research and testing lead to bigger truths about how the world works, such as what diseases might be indicated by a set of symptoms, what metallic alloy holds up the best under extreme heat, or even which teaching method leads to the highest student performance. Such experiments are controlled and then reviewed by other scientists or scholars to make sure they were done correctly. In this way, people collectively create new knowledge, which leads to our next section.

terms to know

Research

Investigation guided by a specific question.

Testing

Various methods of gathering new evidence to see if theories are correct.

3. Facts vs. Knowledge

So far, we’ve talked about truth as facts, things that can be observed or tested. But a lot of knowledge isn’t about real-world facts, but about how those facts are organized or how humans use those facts. Statements like this might be described as true, but it is more precise to say they are accurate or correct.

EXAMPLE

You may know that mice are rodents. But this isn’t the same as knowing the grass is wet or that the snow is cold. Knowing that “mice are rodents” isn’t a statement about mice, it’s an accurate statement about how humans organize and label mice.

The facts don’t change, but knowledge is always changing. As people learn more about the universe, as they gather more evidence, as they devise and run more sophisticated tests, they elaborate on collective human knowledge and understanding of the facts.

EXAMPLE

At one time it was accurate to say that “rabbits are rodents,” but now it is not. Nothing about rabbits changed, but scientists realized that rabbits are more different from mice than they first thought.

When knowledge changes—like rabbits being moved from “rodents” to their own category, Leporidae—it does not mean that earlier facts were wrong, or that the experts are trying to con you, only that the understanding of the facts has changed.

EXAMPLE

When Pluto was reclassified as a dwarf planet in 2006, it was due to an international association of astronomers refining the meaning “planet” rather than any new facts about the celestial body called “Pluto.”

In terms of determining “what is true,” it is important to distinguish “true facts” (observed qualities of natural phenomena or human activity) from “accurate knowledge” (things that are true within an established framework that helps organize, label, and explain natural phenomena or human activity). An easy way to distinguish between the two is to ask if the matter can be proven with physical evidence or only by looking it up.

For some, a distrust of science is rooted in the fact that it is always changing, but the fact that scientists “change their story” is due to the nature of science itself.

EXAMPLE

A lot of astronomy buffs were angered by the change to Pluto’s classification, and may argue that it is still a planet. But “Pluto is a planet” is only meaningful within the classification system that astronomers have created for organizing and labeling objects in outer space. While saying that “Pluto has an atmosphere,” or making other arguments in favor of its planethood can be factual, “Pluto is a planet,” is not true and (for now) not accurate.

An informed, reasoned opinion is built on facts and knowledge. Astronomers know facts about the known universe, and also have knowledge about astronomy itself, or "knowledge about the knowledge." They know that this particular definition has been useful, or that another definition has not been useful, leading to confusion or inconsistency. In the case of Pluto, there are at least four other orbiting bodies that are similar, but for historical reasons have not been categorized as "planets." Astronomers realized that they needed more clarity and consistency, and so poor Pluto was demoted.

Critical thinking requires this ability to discriminate between facts and knowledge; to know that knowledge is an attempt to better organize, understand, and use facts; and that knowledge is always growing and changing as we learn more facts about the universe.