Medicine and Metaphysics: Advancing Our Understanding of the Body

From a lecture series presented by The Great Courses

How do science and philosophy work together? In the new scientific paradigm of modernity, where do concepts come from? Examine how evidence and ideas have come together in modern medicine, and how metaphysics and medicine intersect.

2D illustration of a human body

Ideas sometimes come from the thin air, from insight of young rebellious scientists, from outside the sciences, from the culture of the times, from the arts, and from chance events and happenings. In this way, if we really want to understand why we have the view of reality we do, we must first understand the science that provides us this view, the evidence on which it stands, and the meaning of the ideas within it. Meaning and metaphysics come together to form understanding, which is the basis for modern medicine.

Unpacking Context

But this meaning that forms understanding often results from the cultural and historical context within which the scientists were working. The culture shapes the science, the science shapes how we see reality, and how we see reality shapes the culture. That continuous interdependent flow of events is what we will be examining.

This is a transcript from the video series Redefining Reality: The Intellectual Implications of Modern Science. Watch it now, on The Great Courses Plus.

Stop bacteria signs
Bacteria are outside invaders whose penetration into the interlocked systems of the body must be stopped.

The revolution of thinking that 18th- and 19th-century scientists began indeed triumphed. Bacteria are outside invaders whose penetration into the interlocked systems of the body must be stopped. We will use anti-bacterial soaps to create a metaphorical moat around us that keep the bacteria from entering. If some bacteria force their way in, our medication will be antibiotic, wiping out the bacteria and, thereby, sterilizing our innards and returning us to health. The war is difficult because these one-celled aggressors are tricky, developing resistances to our weapons and forcing us to come up with new antibiotics with which to attack them. But as superior multi-cellular beings, we will surely triumph in the end. This view has been the way we see the world, the human body, and human health.

Learn more about the anatomy and physiology of the human body

But things are changing. There is a new paradigm out there: One in which our bodies are no longer seen as metaphorical castles with bacteria as the bad guys. When we moved from the Cartesian “body is a machine” view to the Semmelweis “body is a castle” view, there were still some remnant concepts that were carried over. The castle was self-contained. The body is a set of interlocking systems that, when working properly, are sufficient for the full functioning of human life. Yes, we need some things from outside the body. Food is needed for energy, and the building blocks like proteins to grow and maintain the body. Oxygen is needed in the air we breathe, as is sunlight for making vitamin D. But all of these needs are met by the digestive system, the respiratory system, and the skin. We possess specially designed organs whose jobs are well defined and keep the whole body capable of doing what it needs to do.

Metaphysics and Modern Medicine

This view of the body as a castle gave us medicines that are incredibly effective. Antibiotics make sick people healthy. Diseases that were once death sentences are now easily and quickly treatable. But, strangely, some people were getting other illnesses as a result of these treatments. Scientists started looking at the interaction between these medications and our digestive system and they found some interesting things—about 100 trillion of them, bacteria that naturally live in our gut and play crucial roles in our body’s ability to function properly. These are not our cells, not parts of our body, but rather their own beings. They are bacteria and we are their home. For every one cell that belongs to us, there are 10 cells subletting inside of us. And they pay their rent in a whole range of biologically desirable ways.

 Intestinal microbiome
Good bacteria, which lives in the digestive system, helps to break down certain chemicals and make them easy to digest.

Some of these bacteria work hand in hand with our digestive system, breaking down certain chemicals in our food to new forms that our body can take up and use. They create an environment that allows for our immune system to work properly. This ecosystem inside of our bodies—what we call the microbiome—is essential to our remaining healthy. Bacteria are not evil invaders; some of them are our partners and our best friends.

Some bacteria are harmful, and they need to be stopped to cure some ailments, but our weapons were taking out the bacteria populating our microbiome with friendly fire. We were harming ourselves by not realizing that we are not just ourselves. We are not individuals; rather, we are walking communities. The good bacteria inside our gut are essential to our body doing what it needs to do. Researchers are now seeing relations between microbiome imbalance and various diseases like Crohn’s, asthma, and even forms of cancer.

Learn more about which germs in your daily life matter

There is reason to think the increase in obesity may be linked to the harm we are doing to our microbiome. Farmers are using antibiotics to make their animals grow faster and fatter. Why would this happen? It turns out that some of the good bacteria in the gut use up calories. Wiping out the good bacteria leaves these calories to be used in generating body mass. For the farmers, this means more weight, and thus more money for their cows and chickens with less feed put in—a bonanza. But those antibiotics are then ingested by us when we eat the meat and when we take them as medicine. If antibiotics have that effect on animals whose bodies are related to ours, perhaps they are doing the same thing to us.

The Body as a Dynamic System

The old approach to obesity based on the view of the body as a machine would focus on the fact that we spend so much time sitting in front of computers at work, and at home in front of the TV. We are now largely sedentary. Our diet is high in processed foods. These factors are possibly explanatory, and surely they are part of the puzzle. But when we have a new picture of reality, one in which we’re not individuals with interlocking fully contained systems, but rather dynamic walking ecologies, the approach becomes different. New possibilities present themselves for explaining what we see.

This new picture means that everything changes. We speak of having a gut feeling. It turns out the microbiome is sensitive to what we see. There appears to be an incredibly sensitive feedback system according to which very subtle reactions in the brain to what we observe quickly manifests itself in the gut biome, which then has multiple pathways into the nervous system. Our gut does literally affect our reactions to our immediate surroundings in real time. How our brain develops, how our brain functions, and how we behave can depend in part on the bacteria in our gut. There are now things we can investigate and explain that would not have even been conceivable using the old paradigm.

This doesn’t mean we just have more tools in our toolbox; it means that we see reality differently. We’ve redefined what it is to be a person. We’re no longer atomic individuals; each of us is a community. When you walk into a restaurant alone and the hostess asks, “Party of one?” You can now say, “No, party of 100 trillion and we’d like a table with one chair please.” Who we are is not who we thought we were. Our own reality has been redefined. This pattern is repeated again and again. We begin with a scientific theory that sees things as atomic individuals. These independent entities are studied—sometimes literally, and sometimes metaphorically—under the microscope. Knowledge about them is found by investigating them closely and carefully. The human body was a machine. To understand it, we looked at its parts and systems.

Learn more about physics in your body

Soon, we came to realize that we can’t understand reality by looking at the pieces; rather, we need to see them in relation, and so we began to look at a more complicated reality in which there is interaction between elements. We find bacteria and learn how they as individual things affect us, a completely different thing. Eventually, we find that what we have is not a set of individual atomic entities, but a complex interrelated system, a web of interdependence. As humans, we become the hosts of huge microbial communities.

Microbiome , microorganisms on human body
As humans, we are hosts of huge microbial communities.

This pattern will be seen not only in medical advances, but in our discussions of the physical sciences, the human sciences, and the social sciences. The universe, people, and society will move through these different metaphysical states in our best scientific approaches. Human science affects what we think is real. Examining how we’ve changed our picture of reality will help us understand ourselves and the universe around us—as well as that within us.

From the lecture series Redefining Reality: The Intellectual Implications of Modern Science, taught by Professor Steven Gimbel