The presented knowledge bases, which can improve diagnostics in neurology and psychiatry and lead to adequate therapeutic consequences, are not new. It is also obvious that, for example, the outdated interpretation of the barrier function hinders both disease research and adequate therapeutic treatment of patients. In the 95,000 scientific citations on the blood-brain barrier of the last 10 years, the authors speak of impairment in 83%, 76% consider a breakdown and 60% mistakenly consider leakage as the adequate interpretation of their data. Also, the possible role of genetic predisposition in many diseases is constantly and unjustifiably brought into play, which is not helpful for therapy. The concept of gene therapy has predictably failed. But this very idea of gene therapy is based, consciously or unconsciously, on a centuries-long prehistory in the form of preformation, which has repeatedly displaced the ideas of an epigenesis of form (here also of disease). The molecular biology orientation of the biology education of today’s practicing physicians had nothing to counter this creation doctrine hidden in the genetic program of Jacob and Monod. It was only with the (unexpected) findings from the Human Genome Project that Epigenesis was once again raised to the forefront. Making such critical connections visible for our thinking and ultimately also for our (medical) actions is the field of philosophy of science. In this sense, we can ask ourselves why—as with many other socially relevant topics—a refuted theory has not long since been replaced by the existing, better theory.

Since philosophy of science is also subject to fashions, we need to have a critical look at its various ideas.

The Kuhnian model of the history of science, in the sense of a falsification concept introduced by Karl Popper and subsequent paradigm change, occurs in reality as a rare exception at best. The philosopher of science Imre Lakatos even rejected this view that theories must be completely abandoned when they have been falsified, i.e., refuted by experimental or empirical results, as “naive falsificationism”. An important argument of his is that there are no pure data that consist only of observation. Any observation is only possible because it is based on a theory. In short: A falsification can also be wrong. His friend, Paul Feierabend, the anarchist among the philosophers of science, even believes that there is no systematic way to recognize what is right or wrong. He states: “And where arguments do seem to have an effect, it is often due to their physical repetition rather than their semantic content. Once one has conceded so much, one must also admit the possibility of non-argument-related developments in individuals as well as in institutions such as science, religion, prostitution, etc.” (Against Method, Suhrkamp 1995, p. 23).

These are system-immanent, theoretical considerations. We find a completely different context of justification in the social context. Michel Foucault has made significant contributions to this. He has examined the unconscious basic attitudes of scientifically active people in dependence on social, work and power structures in history since the Renaissance. As practicing researchers, we can also directly understand today that both the choice of areas to be investigated and the acceptance of the results obtained from them are determined by society, political conditions and the Zeitgeist (Reiber 2017d).

However, this still does not explain how the existence of controversies that endure all societal systems comes about. Elsewhere (Reiber 2017c), I have shown, using the example of the history of developmental and evolutionary biology since Aristotle, what a millennia-long, parallel, undeterred continuation of two competing narrative traditions looks like: On the one hand, there is the line of Plato’s abstract theory of ideas, religious creation myths, church-supported preformation to the genetic program. On the other hand, there are the theories nourished by observation of Aristotle’s “kinetics” (biological form development), epigenesis, geometric symmetries in shape formation to the self-organization of stable form of the phenotype. The incomprehension of one group for the ideas of the other has led to personal hostilities or even to the burning of the opponent.

With increasing neurobiological knowledge, it becomes clearer that the problem with finding truth is not a scientific problem, nor primarily a social one, but has more to do with a special function of our brains. With the functional lateralization of the two brain hemispheres, we create the competing world experience within ourselves. Both brain halves are structurally and functionally different. The usually left brain hemisphere looks for what it already knows and what fits into its existing ideas, the already learned. The other, the right brain hemisphere, looks for everything that is new and processes even the most complex contexts. This brain hemisphere dreams and contributes to creative, spatial ideas and is also an important basis of emotions. The asymmetry of the brain is phylogenetically old and can be found in all vertebrates. The different function can be as simple as in the chicken, which differentiates grains from pebbles with the right eye and the associated left brain during food search, while the left eye with the right brain turns to everything new, unknown, perceives changes in the environment and recognizes danger from predators. We also see the corresponding head turn for better perception of the unknown in horses.

We need and use both brain hemispheres for all our functions (language, art, mathematics). But the different attentions lead to different constructs, images, ideas about the world, to different realities, which can appear contradictory, incompatible or paradoxical (Reiber 2017c).

The complexity of our individual world experience is already evident in the details of optical signal processing in the brain, e.g. in the function of the lateral geniculate body (Corpus geniculatum laterale) of the visual pathway. In this control center between the retina of the eye and the visual cortex, it is decided, based on the inputs of all possible further sensory impressions, including emotions, what of the images captured in the retina will ultimately be forwarded to the cortex for processing. Since these diverse sensory inputs at the lateral geniculate body have also arisen in subjective learning processes, one could also say, we only see what we have learned to be important for us, or also, we only see what we can or want to see.

The consequences of this divided world of experience with the control mechanisms in our brains are not only evident in the ongoing coexistence of competing scientific theories, but also in social beliefs and disputes, for which the current Covid discussion is one of many smaller examples. A more existential version of different “experience-based” perceptions of the world is the international climate discussion.

From the variety of contexts in the philosophy of science, we learn that many of the mechanisms that stand in the way of implementing new insights are of biological orgin and are subject to learning processes. Just as epigenesis has repeatedly prevailed against creation models, a more complex thinking of the right brain could also prevail against the currently predominant linear cause-effect mechanisms. From what has been said, it is clear that this requires both learning processes of the researching, acting individual as well as much more difficult to effect changes in our capitalist and ideologically oriented societies. We should be able to give more space in our thinking and actions to the qualities emerging from connectivity of all living things and their complex dynamics.