When you stop to think about it, it’s very striking how much better the human body functions on an automatic level than on our usual conscious level. Our hearts beat, our lungs inspire and expire, and many other natural functions proceed almost without our awareness of them, and with very little conscious control. We make complicated machines these days, but none as complex or sophisticated as the human (or animal) body.
Homeostasis is a very basic characteristic of our bodies, but one that’s not easy to understand. The word refers to the constant process of adjustment the body makes to conditions inside and outside. I particularly think about it when I take vital signs–temperature, pulse, respiration, blood pressure–on someone frequently, and see that the values I get always vary slightly, but not very much, unless there’s something wrong. Homeostasis is the process which keeps our functions within the pretty narrow limits where we are healthy. Our planet is situated at the precise distance from the sun which keeps most of us from either freezing or burning. Our individual bodies work to complement that, by keeping our internal functions within a certain range.
And that happens without our conscious control. Suppose we had to consciously make our hearts beat and our lungs work. Assuming the possibility, it could only last until we went to sleep. Then we would die. The autonomic nervous system makes all these systems work, more or less in balance, without our conscious control, and it does this with incredible accuracy, precision, and for a very long time (in most cases). Even damaged hearts can keep pumping for many years.
Beyond these very basic functions are more that most of us know little or nothing about, but which are just as important, though we don’t perceive them. Electrolytes are various chemicals, including sodium, chloride, postassium, magnesium, calcium and phosphorous, which our bodies require, and which must stay within a certain balance to ensure that our bodies work in a correct and healthy way. Too much potassium, for instance, can cause a heart attack. Too little can also make a person very sick. Muscle contraction depends on sodium, calcium and postassium, for instance. Too little any can cause muscle weakness, or severe muscular contraction.
If these electrolytes get out of balance, that can cause other problems. One such condition is pulmonary acidosis, which has to do with lung diseases like chronic bronchitis or emphysema, when the lung loses its flexibility and can no longer expel carbon dioxide. Too much carbon dioxide can cause the body’s pH balance to become too acidic, making the affected person very sick. The process can also work in the opposite direction, called alkalosis, where the pH balance rises instead of falls. Either can make you extremely sick, and ordinarily the body is able to avoid such problems.
The autonomic nervous system controls these levels by the use of hormones intended to raise or lower the various levels. Fifty years or so ago I read a fantasy story in which a man helped out a very small genie, with very limited powers. The genie wanted to reward him, but because of his limited powers, couldn’t give him anything worth more than $1.25. The genie made a woman the man had been lusting after fall in love with him, since the supposed value of the chemicals in the human body were thought to be $1.25 at the time. Now we know that the chemicals in the body have a value of several million dollars at least.
Our digestive and eliminative systems also work automatically, as does the system by which the individual cell gets the glucose it needs to survive. Our brains send signals to other parts of our bodies, and receive signals from them. Our immune systems repel foreign bacteria without our knowledge. We hardly are even aware of much of this happening, let alone the process by which it happens. We take our bodies pretty much for granted, unless we have good reason not to.
All of these systems can have flaws or accidents which affect them. That’s not terribly surprising, More surprising is how often they work well without any difficulties.
The system in our bodies, however sophisticated, is also limited. Put a human in a place where the temperature is significantly too high or low, and they will die. Too much water causes drowning. Too little causes dehydration, which can lead to death. But one significant difference between our automatic system and our usual consciousness is that our system is minimally affected by our ideas, if at all. The automatic system in our bodies is designed for reality, and superbly designed for it. It’s not designed for some fantasy that we may have. So our consciousness, as limited and unreliable as it may be, seems to have been designed for something else.
Ideas do influence our consciousness. It may not be accurate to say that no other animal is influenced that way. Higher mammals have similar emotions to ours, but less freedom to decide what they’ll do. Predators must eat meat. Animals that eat only vegetables are usually prey to some predator. None of these animals has a choice about how to live, but humans do.
Humans can decide whether or not to be predators, for instance. Humans can indulge in sexuality throughout the year, unlike any other animal. In most other animal species males are more impressive, or prettier than females. In humans it’s the opposite. Is all this accidental? Or were we designed to be very different from other animals, though in other respects we’re much the same?
That’s a question about which many people disagree, sometimes violently. I consider the idea that humans evolved accidentally to be quite unlikely, though I wouldn’t go so far as to say there’s no truth to the theory of evolution. On the other hand, I’m not a Fundamentalist either. I don’t consider every word of the Christian Bible (to say nothing of other books considered holy) to be unquestionable truth, nor do I see any necessary conflict between science and religion. Science show us, any time that we are willing to look at its results, that we live in a miraculous world that we usually hardly even notice. Mostly, we don’t even understand our own bodies, let alone the environment we live in, so how can the beliefs that many are willing to kill and die for be other than wrong-headed?
Science, at its best, demands evidence for any assertion. Most of the time our evidence for our beliefs is what someone told us, or what we’ve always felt. Some believe that Jesus’s command to love your neighbor as yourself, is simply a rational way to live. Others don’t believe in that kind of behavior, even though some say they do.
Our bodies operate on a different, realistic plan to adjust to the conditions of life. It may fail to adjust as conditions change, but it will try. Our intellectual, emotional and spiritual beliefs may affect how it performs its duties, but it will still do its best to perform them, even when gravely ill.
Could we imagine controlling our consciousness as effectively as our bodies control the various systems that keep us alive and healthy? To me, that seems a likely (though vague) direction for human evolution to proceed. It’s certainly not a goal that anyone can expect to reach immediately. There may be some people in the world who have something approximating that kind of control, but if there are, they aren’t very visible, and I would assume (perhaps erroneously) that there aren’t many. For most of us, that goal is beyond anything we can achieve, but it might be a worthwhile goal to strive for nonetheless.