Which cannot be seen as absolute truth

Image and reality in the natural sciences

What is truth With this question, Pontius Pilate ends the interrogation of Jesus in the Gospel of John. And with this very question Francis Bacon begins his essay 'Of Truth' in 1625: "What is Truth? Said jesting Pilate; and would not stay for an answer." Gottlob Frege, one of the fathers of modern logic, also wrote in 1918 that it was "likely that the content of the word 'true' ... is indefinable." How does natural science relate to Pilate ‘cryptic question today?

The goal of the natural sciences is to recognize the world around us. That means gaining statements about reality and depicting them in the form of observations and laws. We consider these statements and images to be true if they correspond to the reflected reality. They are subjective and not identical to objective material reality. Therefore, the relationship between image and reality is not a simple isomorphism.

How do we measure truth?

How do we check whether our findings correspond to reality? For a scientist, the most important truth criterion is the test of his ideas against reality, especially through experiment. An essential founder of the scientific method is Galileo. In his 'Discorsi' of 1638 he doubts that Aristotle ever tested whether a heavy stone falls faster than a light one, and describes the experiments on the basis of which he formulated his law of fall. This method is also described by Karl Marx in his second Feuerbach thesis: "The question of whether objective truth belongs to human thinking - is not a question of theory, but a practical question. In practice, people have to prove the truth ... of their thinking." Max Born, one of the founders of quantum theory, also advised realism: "My advice is not to rely on abstract reason, but to decipher the secret language of Nature from Nature’s documents, the facts of experience".

Truth criteria

You shouldn't get a picture, one of the Ten Commandments demands. The images that we make of reality always harbor the risk of not correctly reproducing all aspects of reality. There are many false images of the Higgs field circulating as the cause of the mass in the universe. This includes the image of a syrupy substance. It is wrong because mass is resistance to acceleration and not movement. Astrophysicists often combine measurements of cosmic objects with computer simulations in one image, thus mixing reality and simulation.

A second truth criterion does not concern the relation of the statements to reality, but their inner consistency. They should be logical in themselves and free of contradictions. Gödel's work on the undecidability of statements in sufficiently complex systems guarantees the openness of systems of statements and excludes definitive and absolute truths and theories.

In addition to external verifiability and internal consistency, other truth criteria are simplicity, predictive power and consistency with other knowledge. A theory does not always meet all criteria equally. So you can't experiment with the universe, Darwin's theory of the origin of species makes hardly any predictions, and chaotic systems such as weather and climate or biological structures can be very complex. Even so, we try to model them using simple principles.

Truth is relative

Our knowledge is always historical and limited to a limited scope. If for centuries space and time were regarded as absolute standards, we have known since Einstein that they can be changed at high speeds and under strong gravity. While space, time and energy were continuous for a long time, at the beginning of the 20th century they turned out to be quantized. The classical mechanics is only valid for velocities small compared to the speed of light and for energies large compared to Planck's quantum of action. It is contained and abolished as a borderline case in relativity and quantum theory. Recognizing the limits of our theories is often the key to overcoming them. Physics is the basis of chemistry and that of biology. These areas are also delimited from one another, but canceled out from one another.

Laws are not set in stone, and truth is never final and eternal. While Laplace still dreamed, within the framework of his determinism, of being able to accurately predict the behavior of classical mechanical systems with precise prior knowledge, today we know the fundamental instability and unpredictability of even simple many-body systems.

As described by Thomas Kuhn, the progress of science depends crucially on paradigm shifts. Starting from a current relative truth, we arrive at the next, deeper truth. After a paradigm shift, a theory is often contained as a borderline case in the previous theory and canceled in it. Thus scientific knowledge advances from one relative truth to the next - in the hope of getting ever closer to a presupposed absolute truth. At the same time, our knowledge broadened and deepened.

“An important role in the advancement of science
play the doubt and the determination of the limits of a theory. "

Doubt and the determination of the limits of a theory play an important role in the progress of science. Do gravity and electrical force decrease with the square of the distance, even over the greatest and smallest distances? Do both forces have an infinite range, and are the quanta of light and gravity really massless? Does light also spread on cosmological scales according to the laws of the theory of relativity (that is, the Lorentz invariance applies)?

Wherever possible, physicists test these fundamental laws, for example on the basis of gravitational waves that have only recently been detected or the highest-energy gamma radiation. The constancy of the natural constants is also on the test stand: the strength of electromagnetism (the fine structure constant) varies by less than 1017 and that of gravity by less than 1010 per year. However, particle physicists have shown that both the strengths of the forces and the masses of the elementary particles depend on the energy. So constants are not always constant!

Furthermore, uncertainties prevent us from fully realizing the truth. That is why we try to get closer and closer to the true value of a measured variable through better systematics and statistics of the measurements.

One example is the discovery of the Higgs boson at the LHC (Large Hadron Collider) at CERN. In view of the existing uncertainties, the General Director of CERN, Rolf Heuer, announced in a historic colloquium on July 4, 2012: "As a layman I would say: I think we have it… We have a discovery. We have observed a new particle consistent with a Higgs boson. " The press triumphed: "Sensation! God particles discovered! Have researchers deciphered the origin of the universe?"

»Scientific truth can often be found
not reduce to a headline. "

However, several months of data had to be taken before CERN was able to report in a press release on March 14, 2013: "The new particle is looking more and more like a Higgs boson". Immediately the "Spiegel" criticized: "However, it was not without controversy in specialist circles that the results should go public in July". Scientific truth can often not be reduced to a headline. Our knowledge is always limited, both in its accuracy and in its depth. The truth is relative!

Expect the unexpected

New knowledge emerges in very different ways. Due to its precisely elaborated theories, physics often works for decades towards predicted and planned discoveries that then actually succeed. These include the neutrino predicted by Pauli in 1930 and discovered after more than 25 years in 1956, the Higgs particles predicted by Higgs and others in 1964 and discovered after almost 50 years at the LHC of CERN, and those predicted by Einstein in 1916 and discovered by the LIGO laser interferometer after 100 years Gravitational waves.

In the hope of discovering something new, researchers often try to open windows into new territory through improved measurements (e.g. with increasingly sensitive telescopes in astronomy and astrophysics). But there are also unexpected discoveries that often open up completely new areas of knowledge. These include the discovery of X-rays, as well as the discovery of radioactivity and muon, which ushered in the era of nuclear and particle physics.

The law - the truth behind things

The success of our scientific method of knowing the truth is based on two prerequisites: that there are laws behind appearances and that we can recognize these laws.

Both are part of a scientist's faith and a priori of our thinking. Belief in the law and the search for it became an important driving force of Western thought through the story of God's proclamation of the Ten Commandments. Did the laws prevailing in our world exist before they came into being in the Big Bang?

The Old Testament begins with the story of creation, in Hebrew the book of Bereshit or 'in the beginning', and says that in the beginning there is chaos or chaos. The New Testament, on the other hand, begins with the Revelation of John and means that it begins with the Logos, the Word - or the Law. Here epistemology must clearly define the role of law and truth.

Today mathematics is the language of the law. An exciting question is whether we generate the laws of mathematics through our thinking or discover them as in the natural sciences.


The first atomic hypothesis based on scientific observation was formulated by the English chemist John Dalton in 1808. He asked exactly the right question: Why do continuous substances react in relation to whole numbers? However, Dalton could not provide an experiment to directly confirm his hypothesis, and it was almost a century before the last physicist had given up his resistance to it.

Today the idea of ​​a multiverse is one of the most controversial hypotheses in modern science. Its proponents never claimed to have developed an empirically proven theory. Nevertheless, physicists and philosophers alike often criticize them that the concept does not satisfy Popper's principle of falsification.

If, in the cognitive process, as in the development of the atomic concept, we push the limits of our knowledge, it is legitimate and often unavoidable to make hypotheses without being able to immediately specify procedures for their verification or falsification. Dogmatic prohibitions on thinking would be the end of science at this point and were never intended by Popper.

Atomic hypothesis, gravitational waves, Higgs particles and neutrinos waited for their confirmation for 2000, 100, 50 and 25 years, depending on how early the idea arose and how quickly the experimental technology developed. A scientist don't say never!

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