Immanuel Kant

Kant, supposedly, was the most boring person to have ever lived. He walked the same path at the same time every day with the same person. He was a merely decent student and never married. He never went farther than 65 miles (110 kilometers) from his home town. He died quietly: no poison, no barbarians, and no bursting bladders. My students take a kind of glee in this. What a bunch of bores and weirdo’s philosophers are!

And yeah, sure, they are. But Kant could have lived in his grandmother’s bedroom, even slept in her nighty for all it matters. Kant is the most important philosopher to have ever lived. If his ideas are not exciting, no ideas are. He put the world on a different footing. He is a mountain that casts a shadow over all of philosophy—and would cast one over science, too if only scientists would listen.

He is also incomprehensible.

Kant wrote two huge and insanely difficult books. Then he wrote two small and insanely difficult books to make the big ones easier to understand. They don’t. They’re just shorter. Still, nobody now reads the big ones.

Kant’s book on ethics one is called the Metaphysics of Morals and the metaphysics one is called The Prolegomena. See how confusing he is? Not even his titles make sense.

Kant’s ethics

In ancient philosophy (everything before Descartes), ethics was about personal life. It was about your own happiness and leading a life of meaning. Aristotle had a few good rules, Epicurus had 40, and Marcus Aurelius had hundreds.

Modern ethics has nothing to do with that namby-pamby, personal-fulfilment nonsense. Modern ethics is all about judging, and, instead of having hundreds of guidelines, each of the two main schools of thought (we’ll get to the other school, Utilitarianism, in a bit) has only one rule.

They have a single rule for a simple reason: one rule never contradicts itself. Ethical dilemmas happen when rules come into conflict. Take, for instance, the rules of Salvatore Lo Piccolo, the boss of bosses of the Sicilian Mafia. He was a murderer, drug trafficker, and extortionist. Oddly, though, he was captured with a list of ten ethical commandments for Mafiosi. Here are two: ‘“Always be available for Cosa Nostra, even if your wife is about to give birth”, and “Wives must be treated with respect”.

Well these are good rules, especially for a murderer, but they clearly conflict. If the caporegime calls while your wife is having birth, you can’t win. You will have to break one of the rules.

You might think that adding another rule, “Wives are more important than capos” might help. It does not. An eleventh rule only creates more problems further down the line. Having only one ethical rule is the way out. A single ethical rule cannot come into conflict with itself.

Part of an ethicist’s challenge, then, is coming up with a single rule to govern (and judge) all human action. This is tough, because there are a few tensions. The rule must be big enough to cover everything (“Thou shalt not covet thy neighbour’s wife” won’t work) but powerful enough to decide actions (“Do the right thing” is hopelessly vague).  It has to avoid the most obvious contradictions with common sense (“Do whatever makes you happy” will make other people very unhappy) but also be a guide that is better than your gut.

There has been one good rule passed down through millennia, the Golden Rule: “Do unto others as you would have them do unto you”.  This is surprisingly great. It requires you to treat yourself no better than others, and it dictates exactly what you should do. If you want to steal, for instance, you have to reckon with the fact that your action creates harm and that others have the same feelings and entitlements as you do.

Kant’s ethical rule is almost the same as the Golden Rule. He says, “Act only according to that maxim whereby you can at the same time will that it should become a universal law.”

A “maxim” is a generalized rule to govern your actions. To judge an ethical action, Kant says I should:

  1. Isolate my action
  2. Consider the rule governing my action
  3. Make that maxim ‘universal’
  4. And see if it leads to contradiction
  5. If it does, I am forbidden to act in that way

So, if I want to lie to my wife, my thought process might go like this:

  1. Red Alert! Red Alert! My wife is asking me if I ever find other women attractive. Lie! Lie!
  2. My maxim is “I will lie to my wife”.
  3. The universal maxim is “Everyone should always lie”.
  4. But if everyone were to lie all the time, lying would lose its power, and lying would become not lying. Lying only works if most people are truthful. If everyone always lied, each of us would just add “not” to every sentence we heard to get to the truth.
  5. So I cannot lie to my wife. I must tell her the truth.

Kant’s system improves on the Golden Rule by being completely a priori. This is remarkable, because it means you do not need to look at the consequences of your actions to see how good you are. (The truth of a priori facts can be decided without looking to experience.) Whether you did the right thing depends only on your logic and your maxim. Actions, he says, are acceptable if their maxims never lead to self-contradiction.

Kant is amazing. He has brought ethics, a squishy field of very human interaction, and turned it into something much like logic or geometry, a purely mental, extremely rigorous, right-or-wrong discipline. With Kant’s ethics, you never need to measure your behaviour by what you accomplished. You only ever need to measure it by what you intended.

He is a ‘deontologist’, someone who believes in duty and following rules. Not all ethicists are deontologists; others believe, for example, that the outcomes of your actions matter most. Many utilitarians, for instance, would say that I should be allowed to lie to my wife if it keeps the peace. Her happiness and my happiness are most important.

Kant’s metaphysics

Kant’s metaphysical theory is harder to understand. Hume (he’s also in this book) destroyed any hope of understanding metaphysical ideas, and Kant said that Hume had “woken me from my dogmatic slumber”. Kant set about prove him wrong. His solution is not very grandiose or sweeping, but it is just about right; he says, in short, that we see the world through metaphysical lenses—for example, our experiences are always in three dimensions, forward in time, and with causes and effects.

Wait, you say. Don’t we learn things? Yes. But if knowledge comes from the senses, how can we trust it? And what do we really know?

  1. Human senses are terrible, and
  2. Extrapolating from them is impossible

You might think that the first problem is the big one; after all, our senses are wrong all the time.  Things that seem small are actually big and far away; a warm pool seems cold when you have been sitting on the deck; I can’t hear my wife, even though I can see her mouth moving.

The second problem, though, is a killer. Hume said, in short, you have never seen one thing cause another thing.

You’ve probably heard that drinking a glass of wine a day prevents heart disease; that joyful fact is printed over and over again, year after year, because it shows how just how kind the universe can be. It’s a shame it isn’t true. Some third thing causes people to drink wine and live longer. It’s money. Rich people live better, can afford better health care and gym memberships, and they also can buy good hooch. Wine and longevity are correlated, not causally related.

Hume takes this idea and runs with it. When have you ever seen a cause? You haven’t. All you ever see is correlation—even when you see one billiard ball crash into another, you do not see the first ball cause the second ball to move. There are two events, and we assume that one causes the other.

This drove Kant nuts. Without causality, there is no science. And, obviously, if we have no science, we know very little indeed.

If causality is not observable, it is probably ‘metaphysical’. Metaphysical questions are really frustrating, because they are important but unanswerable. What is a law of nature? What is a substance? What is the soul? How infinitesimally small things does it take to make a finite small thing? Is nothingness something?

Metaphysics is a graveyard of good ideas. Oceans of ink have been spilt on these questions, and not a single truth has floated to the surface. It is enough to make any sensible person despair of ever finding an answer. Kant, though, is not sensible.

He thinks that it might be possible that some of these questions (like ‘what is causality?’) make sense, while some ideas (what is nothingness?) do not. The good ideas have something in common, and he tries to explain what it is.

Kant doesn’t want to solve these problems. He wants to just say which ones are answerable and which ones are not. He hopes to save metaphysics and put it on a secure, more scientific footing. Saving causality is a very important part.

Metaphysics turns out to be a lot like math: it comes from within our own minds, and we can learn things from introspection. This helps Kant a little–but how do we get to universal truths, true for every person, if we are looking only within our own minds?

If Kant were alive in the 21st century, he would say that we have neurological or cerebral structures that limit the way we see the world: we see it (and can only see it) in three dimensions, going forward in time, and logically.

What can we learn from these structures? Quite a bit, he says. All of geometry is in there (it is the science of dimensions), as is arithmetic. Metaphysics and logic are in our minds as well.