Evolution has brought us a tree of life in which the problems are solved with bodies – bodies that breathe and bodies that eat, bodies that grow and bodies that heal, bodies that walk and dig and swim and fly. On that tree of life is one anomalous species which comes in the form of the human body. It is ancient, flawed, and exquisite.
We are fully embodied beings. Our thoughts emerge from and with and of our bodies.
Your body is not at your command, or failing you, or getting fit, or struggling with illness—you are it and it is you. If your body and mind do not feel integrated, you have, in some form or another, disintegrated. It is time to find re-integration.
All this talk of bodies should raise a question, however. What is a body?
A body has division of labor. That is, it contains multiple, distinct parts which are not interchangeable. Consider living organisms that do not have bodies: bacteria. Bacteria often form colonies, which are teeming masses of individual cells. If you take some of the cells away—any of them, most of them even—the colony is smaller, but its fundamental nature is unchanged. It has become a smaller, teeming mass of individual cells. There is no division of labor among the cells. Thus, bacterial colonies are not bodies.
Kangaroos have bodies, though, as do salmon, and dragonflies, and howler monkeys, and boa constrictors. Bacteria do not have bodies, but all of these animals do.
If you take part of a body away, you have changed its fundamental nature, even if it can survive the insult. Many salamanders can regrow fingers, hands, even whole limbs, after an injury. This seems extraordinary to us—and it is!—but the fact that we can observe their transformation, from whole to damaged to growing back into wholeness, is evidence of their embodiment.
Thus, bodies have division of labor. The parts of a body also have structure.
Bodies have structural molecules. You will have heard of some of these molecules, such as collagen; others you may not have not heard of, like proteoglycans and hydroxyapatite. Structural molecules all have different properties. Collagen is like rope, with a high tensile strength that gives it an ability to twist and stretch. Proteoglycans act like sponges that, when full of water, are squishy like jello. Hydroxyapatite is a crystal, and is like concrete—very strong in some directions, but not very capable of resisting forces in other directions. When present in specific ratios, these molecules, and a few others, create the larger materials with which we are more familiar, materials like teeth, bone, and cartilage.
Thus, the parts of a body have structure. They are also connected.
The parts of the body are connected to one another through molecular rivets that act like glue. Some of these molecular rivets will bind to almost anything; others are so selective that they will only attach to other cells of the same type—skin to skin, bone to bone, and the like.
Thus, the parts of a body have structure and are connected. They also communicate.
The parts of the body communicate with one another, again through molecular signals. The growth of muscles and bones is coordinated. Sensory neurons receive information from the world, motor neurons send instructions regarding how to act out to the world, and there is communication in between. Cells send molecular signals to other cells, which may respond by proliferating, or by making new products, or even by dying.
So: bodies have division of labor, and their parts have structure, are connected, and communicate one another.
Finally, to wrap up the question of what a body is, bodies have emergence. The whole is greater than the sum of the parts. You could try to enumerate everything about your body—your bones and your skin, your hormones and your glands, a map of your brain and of your circulatory system, your eyes and liver and kidneys—but even so, you will be missing something. All of the parts combine to make something more than what we have yet been able to name. That is true of bodies.1
This particular approach to understanding bodies is from the excellent, highly readable, and very much recommended book by Neil Shubin, called Your Inner Fish (2009). Specifically, his chapter 7, “Adventures in Body Building.” Pp 116-119.
"Your body is not at your command, or failing you, or getting fit, or struggling with illness—you are it and it is you. If your body and mind do not feel integrated, you have, in some form or another, disintegrated. It is time to find re-integration."
Ah yes.