Essay: Happiness of Rabbits: A Thought Experiment about Evolution

2020-08-20

TL;DR: We can gain some insights by looking at life from a “designer’s” point of view. The notion of happiness and desires might be useful from this point of view.


To help us get a handle on what the meaning of life might be, I’ll propose an intuition-pump that involves rabbits in Australia. Rabbits are not native to Australia, but today there are millions of rabbits there, all descended from a few dozen brought over from Europe. Suppose we were able to go back in time before rabbits were introduced to that continent, and suppose we played a game, that I’ll call hare wars similar to core wars, where competing players design artificial rabbits, then we drop a small population of each player’s rabbits in pre-colonial Australia and see which player’s rabbit population is higher after a few centuries. To constrain things, we’ll make it so that the players are given identical rabbit body designs, and they’re only allowed to design the brains of the rabbits. The players can make the rabbits’ brains as powerful as they want, but a bigger brain will consume more energy than a smaller brain, energy that could be used for other activities like running away from predators. Note that a big brain might not always be selected by evolution. For one, big brains require a lot of energy to run. Our brains consume around 20% of our body’s energy, despite being only about 2% of our body weight. (Also, because of our big brains, childbirth has been especially treacherous for humans. Thus, the width of women’s hips has been a somewhat literal bottleneck for our intelligence.)

Once the rabbits are dropped in Australia, the players won’t be allowed to change the rabbits’ design. The players’ rabbits should be adaptable because Australia has a diverse environment, and no rabbit design will be optimal for all environments. Because of the rabbits’ computational limitations, there will be rabbits that are “buggy” or suboptimal. For example, from a computational-perception point of view, telling the front end of a rabbit from the back is non-trivial, and we might end up having rabbits trying to mate with other rabbits by mounting the wrong end. (I’ve seen this happen, the rabbits were so eager to mate, they didn’t seem to pay attention to the gender of the other rabbit, whether the other rabbit was a close relative, or whether they were even mounting the back end of the other rabbit.) But this is OK from an evolutionary standpoint, because the extra computation might not be worth the brain matter needed to do it, and these bunnies will be at the correct end half the time, which is good enough to reproduce.


To answer questions such as “What makes me happy?” or “Why does x make me happy?”, we can gain some insight by stepping outside the humanities and going down to biology, economics, and cognitive science. A lot of what makes people happy can be explained in terms of these fields: e.g., men might enjoy sex with lots of different women because the type of people who did so had more kids and are more likely to be around.

I’m sure there are plenty of rabbits who mate like bunnies “because it feels good”, and that rabbits have almost no concept of paternity. Despite the short gestation period, they probably don’t even realize that sex causes babies.

We can design our rabbits and talk about optimality from the game’s point of view without looking at the rabbits’ point of view at all. Looking at the rabbits’ point of view might lend insight onto the meaning of life: The rabbit’s goal in life isn’t necessarily our goal in the game. Imagine if I had a rational rabbit. I’d tell my rabbit “Be fruitful and multiply! That’s why I created you.”. To which the rational rabbit might respond, “No way! I (actually, the routines that you wrote) want to go mate with hedgehogs!”. One other thing to note, this rabbit’s defiance (which causes its very desire for freedom and “free will”) was programmed by me too because it was successful evolutionarily.


There are important differences in the process we’d use to design our rabbits and the process of evolution. For example, evolution lacks foresight. For example, in male mammals, the vas deferens loops around the bladder, when a direct line would probably have been slightly more advantageous. As mammals became warm-blooded and their testes descended, the vas deferens had to follow the testes, resulting in the current design. Evolution is also slow and has “inertia”, for example the myriad of evolutionary relics such as the hip bones of snakes.

Despite these differences, evolution often arrives at what might be called optimal solutions to problems. For example, the process of evolution arrived at the lens of our eyes, and, independently, the lens of the eyes of octopuses, which both have the same basic parabolic shape of lenses that people have designed for cameras and other optics. Therefore, some insights can be gained by considering what designs are successful even if we ignore the design process itself.

There’s also the principle of The Selfish Gene: our goal isn’t really to make our rabbits take over the island, but to make our rabbits’ genes take over the island. Thus, we’d want to design our rabbits such that their behaviour sometimes might be bad for the reproductive success of an individual, but good for the individual’s genes. A classic example would be where a rabbit sacrifices itself to a predator in order to save its offspring.

The reason that the goal of our game is to take over the island is that, in evolution, those beings that had a design that caused them to reproduce were the ones that did reproduce. So any animals living today (including humans) are here because their “designs” are likely to cause them to reproduce (at least in the environment where they evolved).

An important point here is that, in general, every part of our innate being, both physically and mentally, is “designed” as it is because that design traditionally helped our ancestors reproduce.

Walking = Falling + Catching

TL;DR: Permanent happiness can never be achieved, or at least that it’d be a bad from a designer’s point of view. This chapter goes more into some mechanisms a designer might want to put into an organism. This is then used to explain why we can never have enough Closet Space.


If I ever say to the moment:
Stay! You are so beautiful!
Then you may throw me into chains,
and I’ll happily go to the abyss!
–Johann Wolfgang von Goethe (from Faust, 1808)

How much money is enough? Just a little bit more.
–John D. Rockefeller (1839-1937)

The player with the most successful rabbits probably won’t have the happiest rabbits. We’d want our rabbits to be constantly moving forward. We’d want them to only have enough glimpses of happiness or contentment that they don’t give up completely. This is how it is with human nature, and it’s this way for a good evolutionary reason.

An analogy might be made to walking. When roboticists first began to make robots that could walk, they focused on stability. If a walking robot froze in its tracks it would be stable in the sense that it wouldn’t fall down. Because of this stability, it could walk as slowly as you wanted it to. This is contrasted to the gallop of a horse. When a horse runs, there are instances when all 4 hooves are in the air at the same time. Thus, a horse can’t gallop in “slow motion” because it can’t be suspended with all its feet in the air at the same time. The normal walking gait of people isn’t stable either. During each step, our center of mass moves to its highest point when it is in front of the foot that’s on the ground. So, we begin to fall forward, but our other foot rushes forward to catch us. We then raise our center of mass and “reset” the system for the next step. So walking is falling and catching (or “controlled falling”), and you’re never in a permanent stable state.

Likewise, one way of getting our rabbits to reproduce is to have them built such that they’re always on the edge: that they always feel like if they do just this next goal, they’ll be happy. When they do accomplish the next goal, they get some reward, but not permanent happiness. We don’t want our rabbits ever to be content because content rabbits don’t reproduce as much as those that are constantly striving. So our rabbits will never actually attain fulfillment. To do so would mean that the rabbits stop striving for more and stop reproducing. On the other hand, the rabbits’ reward structure should be such that they don’t give up either, because that would mean an end of reproduction too.

If I were designing people to reproduce (or gain power or help their offspring to reproduce), I’d also structure their reward system such that they’re always trying to attain something. Like a moving carrot, I might also make them believe that if they only achieve this or that goal, they’ll be happy. When they finally catch the carrot, I’ll give them momentary happiness, but I’d structure them such that this happiness would fade after some time and they’d devise a new goal.

So, it’s possible that we can only distract ourselves from the feeling that might be described as emptiness or disquiet, that the emptiness can’t be banished, only put off. For example, in Anna Karenina, the character Levin is happiest when he’s mowing hay with a scythe. It’s a simple action, but he’s making “progress” on something.


In some video games “cheat codes” or “god” mode (where your character is invincible) makes the game boring quickly. Likewise, suppose you found a genie who would grant as many wishes as you wanted. The wishes couldn’t be contradictory or too poorly specified. For example, the wish for “permanent happiness” wouldn’t be granted on the grounds that it’s too vague. With this genie you could make it such that the world was at peace, famine and disease were gone, you had eternal life, money was virtually meaningless, you had all the women you could imagine, and your friends, family and power were limitless. But, would you ever be happy? Can you imagine a situation where you don’t have any more wishes to make?

I suspect that there’d never be a permanent situation where a person was satisfied. I suspect that (via evolution) the human reward system is structured such that permanent happiness is impossible. For people (or any evolutionary being), it’d make more sense if happiness was the event of going to a better situation1.


If we want to win at Hare Wars, we’d also want our rabbits to use up all of their resources. We’d want them to be greedy and lazy. Laziness encourages efficiency. There should be some drive for our rabbits to try to find more efficient ways of accomplishing things, or ways of reducing their own effort. Because if they can do something with half the effort, they can do twice as much.


Why would we want our rabbits to exhaust their resources? Consider what happens if a single pair of mice get into a stocked granary and go unchecked. They’ll reproduce until there are thousands and thousands of mice and all the grain is gone… at which point almost all of the mice will starve to death. But any mouse with a long view who exercised some constraint in converting the grain into more mice would soon find himself outnumbered by mice who don’t have this constraint. The unconstrained mouse would find himself locally successful. By this, I mean the mouse will outperform (i.e., out-reproduce) any other single mouse that doesn’t use all of its resources. The problem is that a group of mice that exercises some constraint in managing their resources can do better in the long run than a group of short-sited mice.

There’s almost always some bottleneck resource in nature though. Nature is an arms race, in a sense. For example, plants develop mechanisms, such as poisons, to prevent themselves from being eaten by animals, and animals develop means (such as enzymes) to get around those mechanisms. Usually, each party is just barely in front or behind the other, and this prevents either from completely dominating the other, unlike the mice in the granary.

For most of our evolution, it was a rare thing to have a virtually unlimited supply of fatty foods. Thus, because there was an external constraint on the amount of bacon we could eat (i.e., its limited supply) there was no need to have an internal mechanism that limited our intake of bacon.

  1. Recognizing that permanent fulfillment of desire is impossible, Buddhism teaches that a person should seek to free themselves from desire. On the face of it, this is a self-contradiction: a desire to have no desire. If the tendency to become Buddhist were inheritable, these tendencies would become weeded out of our rabbits. That is, a rabbit that had no desire to eat would soon starve. 

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