The Cancer Journal - Volume 5, Number 6 (November-December 1992)


Ludwik Fleck was born in Lwow on July 11, 1896. In 1922, at the age of twenty-six, he received his medical degree from the Lwow University. He served as assistant to Rudolf Weigl, a well known typhus specialist at Lwow medical school. He then specialized in bacteriology in Vienna, and headed the bacteriological and chemical laboratories of the State Hospital in Lwow. From 1928-1935 he was head of the bacteriological laboratory of the Social Sick Fund in Lwow. He was an expert in microbiology and immunology, that was then known as serology.
During his medical studies Fleck was also interested in philosophy and after graduating he continued devoting his time to philosophy, sociology and history of science. Most of his publications on philosophy were written in Polish. In 1935/36 Fleck published his major philosophical monograph, "Genesis and Development of a Scientific Fact" (1), written in German and translated into English, forty years later.

During the Nazi occupation Fleck served as a physician in the Lwow ghetto where he discovered that urine of typhus patients was a good source of rickettsial antigen and could be utilized for the development of a vaccine. In 1942 he was arrested by the Germans and forced to develop the vaccine for the German forces, after which he was deported to Auschwitz. He survived and emigrated to Israel where he headed the Department of Experimental Pathology at the Israel Institute for Biological Research in Ness-Ziona. Fleck was actively involved in medical research and discovered the leukergy phenomenon. Ludwik Fleck died in Ness-Ziona on July 5, 1961 at the age of 64.
Before 1977, Fleck's philosophical work was completely unknown, when Trenn and Merton translated his monograph, "Genesis and Development of a Scientific Fact" into English (1). At the same time W. Baldamus assigned his student T. Schnelle to study Fleck's publications systematicaIly. Schnelle's study Has recently been translated into English and serves as main source on Fleck (2).

Fleck is interested in the philosophical theory of reality rejecting any absolute and objective criteria of knowledge. There is no objective and absolute truth. Truth in science is a function of a particular thinking style by a group of scientists, or thought-collective. A thought-collective is "a community of persons exchanging ideas or maintaining intellectual interaction". The individuals of a thought-collective share the same thought-style. Truth and falsehood in science are meaningful only within a specific thought-collective and with respect to a given thought-style and depend on the purpose of investigation. Different views can be equally true (3).

For Fleck, facts depend on particular thought-styles varying in a non progressive way with time and culture. A scientific fact does not exist, rather it develops: "Sciences do not grow as crystals, by apposition, but rather as living organisms, by developing every, or almost every, detail in harmony with the whole". "The process of cognition is not a two-term one...It does not occur solely between an abstract subject and an equally absolute object. The collective is incorporated into this process as a third member"."Between the subject and the object there exists a third thing, the community. It is creative like the subject, refractory like the object, and dogmatic like an elemental power".
Fleck's notion of the relativity of truth originates in medicine. According to Fleck diseases do not exist in nature but are constructed by physicians for didactic reasons. "It is easier to find one's way in a forest than in botany. It is easier to cure a patient than really to know what his disease is". Yet this very nature of medicine is regarded by the exact sciences as non scientific. It appears as if medicine is more an art than a science. Not to Fleck, who claims that even in the exact sciences facts are not absolute and they develop. There is no absolute truth even in physics, and the physical scientific fact evolves and develops exactly as in medicine. Even in physics it is impossible to separate the object from the subject, and both are influenced by the sociology of thought. "We approach the ideal 'absolute' reality not even asymptotically since it changes incessantly, renews itself and moves away from us at the same pace as we are advancing ".

In the era of the "Big Bang theory" that describes the evolution of the universe (4), such a philosophy seems untenable. According to Hawking the universe is governed by universal and absolute mathematical laws. This view underlies modern physics. Yet the existence of this idealistic view of the universe is threatened by a new scientific revolution known as theory of Chaos, that claims that nothing in nature is absolute. Statements, facts and truths are relative (5,6). This sense of the absolute, so typical of physics, and deeply embedded into its thought-style will from the view-point of other thought-styles always remain relative.

No wonder that Fleck's revolutionary ideas were rejected. His philosophy was resurrected only after Thomas Kuhn prepared the scientific community for accepting it with his "Structure of Scientific Revolutions" (1962). Philosophically Fleck was also a forerunner of Chaos theory. Now that the number of his followers is growing, his philosophy will be updated in light of modern technological innovations and the Chaos revolution.

Fleck applied medical reasoning for demonstrating the relativity of truth in science. In spite of being an epistemologist, Fleck is first of all a philosopher of modern medicine who introduced the notion of the relativity of diseases. The definition of a disease is arbitrary and depends solely on the thought-style within which it is studied. Each discipline involved in medicine defines the disease in a different way; e.g., "sore throat" that has different meanings to a clinician, bacteriologist, or an epidemiologist. Superficially it appears as if all are dealing with the same phenomenon, which may be extremely misleading particularly when the disease is treated.

Similar difficulties exist in oncology and may explain its current conceptual confusion. Each discipline involved in cancer research defines the disease from a different view angle and the main difficulty of oncology is to decide which cancer concept to apply. Is it a parasite, or a mutated gene: or could it result from the breakdown of immunological surveillance? Cancer should first of all be defined within the clinical thought-style, a disease with three ingredients: neoplasia, para-neoplasia and cachexia. Any thought-style disregarding one of them is inacceptable (8,9)!

G. Zajicek


1. Fleck L. Genesis and development of a scientific fact. The University of Chicago Press, Chicago USA, 1977.

2. Cognition and fact. Materials on Ludwik Fleck. Cohen R.S. and Schnelle T. Eds. D. Reidel Publishing Company, Boston USA, 1986.

3. Lowi I. The immunological construction of the self. In: "Organism and the Origins of the Self". Tauber A.I. Ed. Kluwer Academic Publishers Norwell USA. p 43-71, 1991.

4. Hawking S.W. A Brief History of Time. Bantam Books New York, 1988.

5. Zajicek G. Chaos and Biology. Meth. Inform. Med. 30: 1-3, 1991.

6. Zajicek G. Meta-Analysis and Chaos. Cancer, J. 4:152-153,1991.

7. Kuhn T.S., Structure of scientific revolutions. The University of Chicago Press, Chicago USA 1962.

8. Zajicek G. Hypothesis: Cancer is a metabolic deficiency. Cancer J. 4:356,1992.

9. Zajicek G. Cancer and metaphysics. Cancer J. 5,1,1992.