There is a common belief in America that you are what you are, and there is nothing you can do to change this. Not everyone believes this, of course. And in fact the exact opposite belief, that all of your attributes can be improved with training, also floats around our culture. Both of these beliefs are really myths that could stand for some overt repudiation by science. In reality, some attributes can be easily and straightforwardly trained. Like muscle strength. But others cannot be so easily trained, like height, or genetic disposition to certain diseases. What exactly are all of the attributes that can be trained? Humorously, searching for this on Google reveals but one result, and it is exactly the opposite of what we want: un-trainable attributes.

In order to determine this, we need to investigate the human body to see what we are capable of doing. The body is divided into several subsystems, like bones, muscles, and nervous system. According to this website, these systems are:

• Circulatory system
• Respiratory system
• Immune system
• Skeletal system
• Excretory system
• Urinary system
• Muscular system
• Endocrine system
• Digestive system
• Nervous system
• Reproductive system

(This list doesn’t seem to be comprehensive. What about eyes, for instance? Or skin? We’ll ignore those for now.)

Some of these can certainly be trained, like the muscular system. Muscles can become stronger or have greater endurance with training. But it is not obvious that all of them can be trained. What would it even mean to train the excretory system? Have less smelly poops? Actually, for all I know, this can be trained, and I am just not clever enough to know how. But I have no choice but to ignore the ones I don’t know how to train for now. For the others, here are some ways they can be trained:

• Circulatory system: Cardiovascular exercise will train your heart.
• Respiratory system: Adapting to low-pressure or low-oxygen environments (think high elevation environments like Tibet) can train your respiratory system to be more efficient and require less oxygen.
• Immune system: By being exposed to small doses of diseases, your body can develop immunities to those diseases.
• Skeletal system: By exposing your bones to small amounts of damage, they can become stronger.
• Muscular system: By lifting weights, your muscles will become stronger.
• Nervous system: Your nervous system includes your nerves and your brain. You can obviously train your brain by reading, or solving math problems, or creating art, or any number of other intellectual activities. You can also train your nervous system by performing tasks, like gymnastics, that require good coordination.

The ones I don’t know how to train are the excretory system, urinary system, endocrine system, digestive system, and reproductive system.

It is very tempting to train one thing at a time and forget about the others. For instance, a lot of intellectuals place a much greater emphasis on intellectual training (myself, or at least my former self, included) at the expense of training the muscular system. But why? Surely all these systems can be trained at the same time. Although I will grant that it may be possible, given a finite human life, to train only a subset of them to your genetic potential. Or maybe not.

Let’s try a crude approximation to quantify how much these systems can be trained. Suppose we rank systems linearly so that if you have reached your maximum genetic potential for a system, then we rank it 10/10. And if you have made no effort to train that system at all and are only just trained enough to continue being alive, then we give it 1/10. (0/10 means you do not have that system at all.) Perhaps it is only possible to train one system to 10/10, since we only have to much time, and all the others are condemned to being trained at a maximum of 3/10. Is that really true? Probably not. Probably at least one other system can be trained highly to, say, 9/10, or even 10/10. In fact, perhaps all systems can be trained to be 10/10. Why not? I mean, how can you possibly be sure that only one system can be trained highly? And surely being strong does not condemn you to being stupid, uncreative and unhealthy. Surely it is possible (even if very hard) to be simultaneously strong, intelligent, creative, coordinated, healthy, efficient, etc.

It is possible that some skills conflict with each other. Suppose someone wants to be really good at fitting into small spaces. That conflicts with the goal of having large muscles, because large muscles make it harder to fit into small spaces. But the systems of the human body do not in general conflict with one another. It is possible to have stronger muscles, stronger bones, and a stronger brain simultaneously. They are also consistent with having a stronger heart, more efficient lungs, and better coordination.

Now, what are the steps someone can take to train all of these systems from 1/10 to 10/10?

Previously: The Many Dimensions of Human Excellence.