Ethics: How Do You Know Right from Wrong?

From the lecture series: The Philosopher's Toolkit — How to Be the Most Rational Person in Any Room.

By Patrick Grim, PhD, State University of New York, Stony Brook

Ethics questions…What is right? What is wrong? How do we know that anything has value? When we think something has a certain value—that human life is valuable, for example—how do we know that?

illustration for difficult decision concept
(Image: Huza Studio/Shutterstock)

We do know things about ethics. We know that human life is important and valuable. We know that people have rights, such as taking their own paths in life. We know it is ethically wrong to violate those rights. We know we have obligations to our family, friends, and humanity at large. This is an important kind of knowledge, but a normal kind of knowledge.

The question, however, is not whether we have that kind of knowledge. The question is a reflective question about what kind of knowledge it is.

Learn More: Kant’s Ethics of Duty and Natural Rights

The Intersection of Math and Ethics

There is an approach that sees ethical knowledge not as ordinary empirical knowledge but as extraordinary empirical knowledge. This goes together with a particular view of mathematics. As it happens, in this view, both mathematics and ethics involve a kind of extraordinary perception.

The statue of Plato at The Academy of Athens. Greece.
Plato, the ancient Greek philosopher (Image: Dimitrios/Shutterstock)

Plato thought of mathematical knowledge in terms of geometry; hanging over the entrance to the Academy, his school of philosophy, was the slogan “Let no one ignorant of geometry enter here.” What is geometry about? It’s about concepts like perfect triangles. Your high school geometry teacher may have been a Platonist in this way. He or she may have said, “Here, let me draw a triangle on the board. Of course, this isn’t a real triangle; it has lines that have a thickness, as I’ve drawn it on the board. I haven’t drawn them perfectly straight. What we’re talking about is the ideal triangle that this drawing on the board represents.” But how do we know about that perfect triangle, that ideal triangle, if we can’t draw one, if perfect triangles exist nowhere on this earth?

This is a transcript from the video series The Philosopher’s Toolkit: How to Be the Most Rational Person in Any Room. Watch it now, on The Great Courses.

Simply put, Plato’s theory was that we see those perfect triangles with our mind’s eye. Mathematical knowledge, in such an approach, is a glimpse of a realm of pure forms in which the pure triangle exists. According to Plato, ethical knowledge is similar; it comes not from looking at the physical world, but by glimpsing the form of the good in this other, abstract realm.

Listening to Your Conscience—Ethical Knowledge

There’s a more common view that is not too far from that. It is the idea that we know the ethical value of right and wrong by listening to our conscience. That still, small voice inside is what tells us whether something is right or wrong.

Theories that we know right from wrong by listening to our conscience are troublesome. Click To Tweet

But he problem with Plato’s theory is that it postulates a form of perception—the perception of a realm of being the perfect forms—for which we have no evidence at all. No one has found a mind’s eye buried deep in the brain, and it’s unclear what it would be even if it were found. This doesn’t look like an ordinary explanation for an ordinary kind of knowledge. It looks like a mythical explanation invoking some mythical type of perception.

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Theories that we understand right from wrong by listening to our conscience are troublesome as well. The problem isn’t psychological unreality, as it is in the Platonic case; indeed, the notion of a still, small voice inside does seem to have some kind of psychological reality. The problem is in trying to believe that it is some kind of infallible guide.

Illustration of Jim and Huckleberry Finn, by E. W. Kemble from the original 1884 edition of the book
 by Mark Twain
In The Adventures of Huckleberry Finn, Twain uses Finn’s inner turmoil over his decision not to turn Jim in, as a way of revealing important notions about ethics and conscience. (Image: Edward Winsor Kemble – Project Gutenberg/Public domain)

Where would one’s conscience get its information on what is right and wrong? How do we know that the still, small voice is telling us the truth about right and wrong? Mark Twain makes the point brilliantly in The Adventures of Huckleberry Finn. Huckleberry’s conscience tells him that he should turn Jim in. After all, Jim is a slave. Therefore, he belongs to someone else. Huckleberry berates himself because he helped him go free. His conscience tells him that was wrong—by helping Jim go free, he’s deprived Miss Watson of her property. Not only that, but Jim talks about trying to free his own children. Huck’s conscience bothers him about that. After all, Huck says, those children belong to a man he doesn’t even know.

What we know—and what Mark Twain relies on us knowing—is that Huckleberry’s conscience is not innate and is not infallible. That small voice inside is merely an echo of his acculturation, complete with an approval of slavery typical of that time and place. In the end, Huckleberry Finn defies his conscience and decides not to turn Jim in.

Are Ethics Self-Evident?

There’s another view of ethical knowledge tied to a different view of mathematics. Euclid’s axiomatization of geometry, written in 300 BC, about 50 years after Plato’s, became a model for what knowledge should be like for almost 2,000 years. But in Euclid, not every mathematical question is answered by casting your mind inward, looking for the forms, as Plato would have you do. In Euclid, you begin with a few basic axioms that are taken to be self-evident. You deduce other things from those axioms, by small steps in which the validity of each step is self-evident. You can find out surprising things this way; indeed, all the surprising truths of geometry in this way. The results may be surprising, but they follow by self-evident steps from your self-evident axioms. Is ethical knowledge like that?

Cropped portrait of Thomas Jefferson
Thomas Jefferson, primary author of the Declaration of Independence. (Image: By Rembrandt Peale/Public domain)

Some prominent people seemed to think it was, including Thomas Jefferson. That image of ethical knowledge appears in the Declaration of Independence. It says, “We take these truths to be self-evident, that all men are created equal, endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.” Jefferson formulates the Declaration of Independence as if he is going to put down some self-evident axioms and deduce from them that the colonies have a right to be free and independent. Now even here, one is supposed to see that the basic axioms are true. To that extent, it is still a perceptual view of ethics, demanding some kind of inner eye attuned to the ethical universe.

Learn more about emotions in ethics

Different people seem to take very different things to be self-evident, and that again makes you doubt the self-evidence of ethics as some infallible mode of inner perception.

Unfortunately, different people may claim very different truths are self-evident. George III certainly didn’t think it followed from self-evident truths that the colonies should be free of English control. His self-evident truths were something different; they were beliefs like the divine right of kings. Different people seem to take very different things to be self-evident, and that again makes you doubt the self-evidence of ethics as some infallible mode of inner perception.

If ethical knowledge is not a kind of empirical perception in the world, analogous to scientific knowledge, and if it doesn’t involve a kind of inner perception on either of these models of mathematics, just what kind of knowledge is it?

To address this, what I want to propose is that a large part of the set-up of this question is wrong. Neither scientific knowledge nor mathematical knowledge is really as we tend to portray them. When we have a better appreciation for what other kinds of knowledge are like, ethical knowledge begins to look like those other kinds of knowledge. Ethical knowledge starts to look less different or strange.

Common Questions About Defining Ethics

Q: What is ethics, by definition?

Ethics is defined as a code of conduct as set and followed by a collective of people.

Q: What do philosophers consider as the three types of ethics?

The subgroups of ethics that today’s philosophers have decided define ethics are normative ethics (rules governing behavior), metaethics (the study of ethics itself), and applied ethics (practical use of ethics in everyday life and professions).

Q: Are there any examples of ethics?

Ethics range far and wide and can include the behavior of the employees of a corporation or a cult. Some common examples of ethics might include the Ten Commandments or basic ideals of general tort law in municipalities.

Q: What are the four principles of ethics?

The four principles of ethics are commonly thought to be nonmaleficence (do no harm), justice, beneficence, and respect for autonomy.

This article was updated on July 31, 2020

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