Ontology is the study of being, and the central topic of the field is couched, variously, in terms of being, existence, and reality.
When philosophers study reality is’s called metaphysics. Although they have in the past discussed metaphysical questions from a purely conceptual standpoint, advances in science have forced a reevaluation of some traditional metaphysical views.
The discovery of harmful bacteria causing disease, forced us to reassess how the human body works and how it relates to the surrounding world. This will highlight the connection between scientific theories and our picture of reality as found in the work of historian and philosopher Thomas Kuhn, whose concept of a paradigm illustrates the idea that every scientific theory contains a worldview within it.
Metaphysics: The Study of Reality
René Descartes, known as the father of modern philosophy, began his intellectual odyssey with this question: How do we know that there is a reality outside our own minds? We each know that we have experiences, and we can be sure of these experiences; therefore, each of us can be sure that we exist. But how do we know that the internal experiences we have correspond to objects outside our minds?
You can see, smell, touch, and taste a loaf of bread, but those experiences are in your mind, not out in the world. How, then, do you know that there even is a world out there, and if there is, how do you know that it resembles the world of your internal experience? If all of your experiences are in your mind, how do you know that the thing giving you the bread experiences is, in fact, bread?
Perhaps, Descartes considers, you are merely dreaming or there is an evil damon artificially feeding experiences into your mind, creating a false universe that you wrongly believe is real. Descartes ultimately rejects this hypothesis, in part because there are surprising regularities in our experiences that are beyond our ability to control or create. When we keep careful track of our observations, intricate patterns emerge that can be generalized to systems we had never previously known or imagined.
The study of these patterns of observations is science. We look at patterns and create theories to explain their appearance. These theories, in turn, posit mechanisms that are supposed to be in the world and are responsible for creating the patterns. We can use those theories not only to explain what we have already seen but to predict new observations we have yet to make. If those predictions come true, we take it as evidence that the mechanisms in the theory are likely an actual part of the real world.
In this way, we use our best scientific theories to define reality. When we have new theories that replace our old ones, we not only gain new understandings about how our observations relate to each other, but we conceive of the world itself in new and strange ways. This is where science and philosophy meet. Scientists give us new accounts of how the universe works, and philosophers unpack those theories to see what they tell us about what is real.
The Germ Theory of Illness
According to Descartes, we are made up of two parts, a body and a mind. The body is mechanical and runs according to the laws of physics. The mind (for Descartes, the soul) is non-material and is where the will resides. For centuries, medical science was based entirely on this picture of the human body as a machine.
In the 1840s, Ignaz Semmelweis was an Austrian doctor working in the First Maternity Ward at Vienna General Hospital.
Semmelweis noticed that the incidence of childbed or puerperal fever was quite high in his ward and, schooled in Descartes’s machine view of the body, considered a number of causes for the illness that accorded with that picture.
But when another doctor died from childbed fever after being accidentally cut with a scalpel during an autopsy, Semmelweis considered the possibility that the doctors themselves were a vehicle for the ailment.
He then demanded that people working on his ward clean their smocks and wash their hands with a chlorine solution before assisting with a birth. Childbed fever cases fell dramatically. Semmelweis had identified the cause of the illness; a type of bacteria present in both dead and infected tissue.
This idea, however, was widely rejected. The human was thought to be a machine, and all problems with the machine could only be caused by parts of the machine malfunctioning. The idea that there were tiny animals inside us making us sick seemed silly.
After Frenchman Louis Pasteur’s work, the germ theory of illness became accepted, and we had to change our picture of reality. We were no longer “ghosts in a machine” but castles surrounded by hostile one-celled barbarians. Blood was no longer thought of as oil or hydraulic fluid flowing through our veins; white blood cells were now thought of as armed guards doing battle with tiny invaders. This was a completely different foundation from which to understand human physiology and health.
In the century that followed Semmelweis, this standpoint led to vaccines that eradicated diseases from smallpox to polio and to new ways of life. Cleanliness was not just next to godliness but the source of continued life itself.
Not long after the work of Semmelweis and Pasteur, we find the writings of Jules Verne and H. G. Wells, who posited new worlds at the bottom of the ocean, on the Moon, and back in time. It was a period of great discoveries, and the uncertainty associated with seeing that the world contains things we had never seen before was jarring. The entire genre of science fiction grew out of – and was informed by – the need to redefine reality with our scientific advances.
Kuhn’s View of Scientific Theories
In his 1962 book The Structure of Scientific Revolutions, Thomas Kuhn notes that when we think of the archetype of the scientist, the people who come to mind are Newton, Darwin, and Einstein. But science as it is done on a daily basis by working scientists is not at all like what those towering figures did. Newton, Darwin, and Einstein are revolutionary scientists whose work is different in kind from what Kuhn calls “normal science.” Normal science is quite the opposite of revolutionary.
Normal scientists work within a paradigm that tells them what counts as a legitimate scientific question, what tools they can use to answer such questions, and what counts as a legitimate answer. In other words, normal science occurs when someone poses a question deemed meaningful by the paradigm and uses the tools prescribed by the paradigm to find an answer that is acceptable within the paradigm.
Scientists do not question the paradigm. They teach their students how to act according to it, and challenging it is considered a challenge to rationality itself. Rationality, Kuhn argues, exists only within the paradigm. Because the paradigm tells us what is real and how it works, to question it is to question the structure of the world itself; according to those within the paradigm, that leads to nonsense.
Occasionally, however, anomalies pop up. There are questions the paradigm accepts as legitimate, but when the proper tools are applied, the answer fails to be one the paradigm recognizes. The first reaction is to assume that the normal scientist made an error, but sometimes, even after checking the calculations, the anomaly remains unanswered.
The unanswered anomalies, according to Kuhn, are ignored for as long as possible, until there are enough of them or they are so significant that they can no longer be discounted. At this point, the scientific community is thrust into a crises and is forced to reevaluate the paradigm. If the crisis is severe enough, some will consider the unthinkable: using a different paradigm, a new set of basic concepts, a new structure to reality itself.
These people are seen as nonscientific by those in the community because scientific thought is defined by the paradigm. But if the normal science within the new paradigm starts to look good, some will leave the old way for the new. If a critical mass adopts the new paradigm, the result is a scientific revolution. In the same way that a political revolution completely changes the system of government—that is, one legislative reality is replaced with another – so, too, does a scientific revolution replace one reality with another. Scientific revolutions, according to Kuhn, force us to redefine reality.
The revolution that Semmelweis began seems to have triumphed. Bacteria are outside invaders whose penetration into the interlocked systems of the body must be stopped. But there is also a new paradigm emerging, one in which our bodies are no longer seen as metaphorical castles with bacteria as the bad guys.
As scientists have started looking at the interaction between medications and the digestive system, they have discovered about 100 trillion bacteria that naturally live in the gut and play crucial roles in the body’s ability to function properly. These bacteria break down certain chemicals in our food to new forms that the body can use and create an environment that allows for the immune system to work properly. This ecosystem inside of our bodies, called the micro-biome, is essential to good health. Bacteria are not evil invaders; some of them are our partners.
Some bacteria are harmful, and they need to be stopped to cure some ailments, but our weapons, antibiotics, have also been eliminating the bacteria populating the micro-biome. We have been harming ourselves by not realizing that we are not just ourselves. We are not individuals but walking communities.
Soon, we realize that we cannot understand reality entirely by looking at the pieces; rather, we need to see the pieces in relation to one another. Thus, we begin to look at a more complicated reality in which there is interaction between elements. Eventually, we find that what we have is not a set of individual atomic entities but a complex interrelated system, a web of interdependence.
Carter, Childbed Fever.
Descartes, Discourse on Methods