Reasoning from First Principles
In order to understand better what first principles are and how they may help us, let us first look at different types of reasoning.
Different types of reasoning
There are two main ways of reasoning, that is, ways of figuring out new facts or truths. These are: logical reasoning and analogical reasoning.
Logical reasoning (reasoning by logic) is like this:
Statement 1: All animals eat food
Statement 2: Dogs are animals
Therefore:
Statement 3: Dogs eat food
The last statement follows logically from the first two statements. What this means is that if all animals eat food and dogs are animals, it must be true that dogs also eat food. So if we did not already know that dogs eat food, but we did know that all animals eat food, and that dogs are animals, then we could figure out that dogs eat food via this logical reasoning.
Analogical reasoning (reasoning by analogy) is more like this:
Statement 1: Cats eat food
Statement 2: Dogs are similar to cats
Therefore:
Statement 3: Dogs (probably) eat food too
Analogical reasoning involves making an analogy, i.e. saying that something is like something else. This kind of reasoning can often give us the correct answer because things that are similar to each other in some ways, are often similar to each other in other ways. Since dogs are similar to cats, and we know that cats eat food, then it is quite likely that dogs eat food too. But analogical reasoning is not as precise or foolproof as logical reasoning. For example:
1. Cats meow
2. Dogs are similar to cats
Therefore:
3. Dogs (probably) meow too
This time we got an incorrect answer. Even though cats and dogs are similar in many ways, they are also different in other ways (otherwise we wouldn’t have different names for them!). Cats meow, but dogs bark.
So reasoning by analogy doesn’t always work, but it can be useful in our everyday lives, since it is quick and easy. If the stakes are higher, however, we may want to use a form of reasoning that is more reliable, i.e. reasoning by logic. For example, if we are trying to figure out if a nuclear reactor will explode, we may not want to rely on a reasoning in the form of “well, that other reactor didn’t explode, so this reactor probably won’t explode either”. We may want to use logical reasoning instead, such as
1: if the temperature is above 1000 degrees, then the nuclear reactions will become twice as fast
2: if the reactions become twice as fast, then it will be impossible to stop the reactions from escalating further
3: if it becomes impossible to stop the reactions from escalating further, then the reactor will explode
4: the temperature is now above 1000 degrees
Therefore:
5: The nuclear reactor will explode
The advantage of logical reasoning is that if we have some information that we are certain is true, then we can be sure that the logical conclusion we draw is true too. There is only one problem: how can we be sure that the original information, the first statements, are true? Let’s take the following example:
All dogs have a tail
Fido is a dog
Therefore, Fido has a tail
If the first two statements are true, then we can be certain that Fido has a tail. But is it really true that all dogs have a tail? Could there be dogs that don’t have a tail? In that case it is possible that Fido doesn’t have one either. And so the statement “Fido has a tail” could be false, even though it follows logically from the first two statements. So trying to use logic when we aren’t completely sure that the first statements are true can be dangerous. It can seem like we have arrived at a new truth because we used logical reasoning, when in fact the conclusion is false.
This is a big problem, because there are actually few things in the world that we can be absolutely certain of. To take dogs as an example, there is almost no property that is true of every single dog. Most dogs have tails, but some don’t. Most dogs have fur, but some don’t. Most dogs have four legs, but some have three, or two, or one, or none. Not all dogs bark, not all dogs have a nose (if they’ve been in an accident), not all dogs have ears. And so on. We can take some other examples to illustrate the point further. If we press the light switch in our bedroom, the light will usually light up, but not every time. Sometimes the light is broken. And to take a famous example in philosophy: in the western world it was believed for many centuries that all swans are white, because all the swans that had been observed so far were white. The idea of a “black swan” was seen as absurd, impossible. But over a thousand years later the western world found out that in Australia, there actually are swans that are black. Something that had been considered so certain that it was used as an example of being “the most obvious fact that no one could reasonably deny”, was actually incorrect.
The point is: there are few “facts” that we can be 100% sure of to be correct. There is often some uncertainty, because the world is complex and not simple. This means that most times we use logical reasoning there will be some uncertainty about whether we have arrived at a true fact, even though the logical reasoning itself is correct. Or to phrase it differently: we can rarely be 100% certain of our conclusion even if we used logical reasoning to arrive at the conclusion. This can be a bit of a problem.
Reasoning from first principles
There is a potential solution to the problems of logic: figure out the fundamental, most certain, facts and apply logical reasoning to them. If these facts are certain, then the logical conclusion that follows from these facts will also be certain. This type of logical reasoning is called “reasoning from first principles”. “First principles” can roughly be described as “fundamental truths”; they are the principles (laws, or facts) that must be the starting point for understanding a topic. They must come first, because they are the principles that underlie all the other facts in that topic. If you know the first principles of a topic, then it means that you can derive all relevant facts on that topic just using logic.
Let’s take an example. All animals who live on land need to breathe air with oxygen in order to survive. This is a first principle. It is true for all animals on land. When animals breathe in air with oxygen, they breathe out air with carbon dioxide. This is also a first principle. It is a fundamental fact of the process of respiration. From these facts we can now tackle a question like what will happen if an animal is placed in an airtight box. If the animal breathes in the oxygen in the box, then this oxygen will be replaced with carbon dioxide until there is no oxygen left. From this, we can conclude with certainty that the animal would die in such a scenario. No need to test it in practice to figure out the answer!
Science is full of first principles. Physics is the most exemplary field, where we have first principles of motion, of gravity, of electricity and magnetism, of quantum mechanics, etc. It is because of this that modern engineering is so effective. Elon Musk has explained that the reason why the company SpaceX is so successful is because they figure things out from first principles. It enables them to come up with new solutions that they can be fairly certain will work.
Reasoning from first principles also allows us to discover more easily whether some new information is correct or incorrect. When a physicist claimed that he had observed an event where light travelled faster than “the speed of light”, other physicists weren’t really that interested. With the first principles of physics it was possible to show that it is impossible for light to travel faster than the established value, and so they could feel secure that the new result must be caused by some measuring error. A few months later this is also what the physicist discovered.
Thus, reasoning from first principles is a powerful tool when it comes to dealing with situations in our lives. It allows us to be more secure in the conclusions we draw, to come up with new solutions, and to more easily determine whether some information is correct or incorrect. With an increased ability to reason from first principles we can therefore make wiser choices.
The downside to reasoning from first principles
While reasoning from first principles allows us to figure out new truths, it also has some disadvantages.
- Most areas of knowledge still lack a set of first principles. This means that there are many situations where reasoning from first principles isn’t possible yet. But of course, the purpose of A Wiser World is to change that!
- It takes more effort to reason from first principles. If you are in a situation where you don’t have a lot of time (or energy) then trying to reason from first principles may be too much work, and analogical reasoning may be more useful. Hopefully, though, A Wiser World will be able to collect answers to many questions, and so the individual person won’t have to do the first principles analysis themselves, but simply need to search for it on the platform.
So reasoning from first principles has great potential, but we need to have these disadvantages in mind!
This concludes the section of what wisdom is. We can now move on to the next question: “How do we acquire wisdom?”. What do we need to do in order to gain knowledge of all those parts that are presented in the wisdom model, and to find the first principles?
Next: How do we acquire wisdom?
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