Karl Ludwig von Bertalanffy (19 September 1901 – 12 June 1972) was an Austrian biologist known as one of the founders of general systems theory (GST).

This is an interdisciplinary practice that describes systems with interacting components, applicable to biology, cybernetics and other fields.

Bertalanffy grew up in Austria and subsequently worked in Vienna, London, Canada, and the United States.

Ludwig von Bertalanffy was born and grew up in the little village of Atzgersdorf (now Liesing) near Vienna.

Ludwig's mother Caroline Agnes[2] Vogel was seventeen when she married the thirty-four-year-old Gustav.

Ludwig von Bertalanffy grew up as an only child educated at home by private tutors until he was ten and his parents divorced, both remarried outside the Catholic Church in civil ceremonies.

[3] When he arrived at his Gymnasium (a form of grammar school) he was already well habituated in learning by reading, and he continued to study on his own.

His neighbour, the famous biologist Paul Kammerer, became a mentor and an example to the young Ludwig.

[4] The Bertalanffy family had roots in the 16th century nobility of Hungary which included several scholars and court officials.

Ludwig's father Gustav von Bertalanffy (1861–1919) was a prominent railway administrator.

On his mother's side Ludwig's grandfather Joseph Vogel was an imperial counsellor and a wealthy Vienna publisher.

Ultimately, Bertalanffy had to make a choice between studying philosophy of science and biology; he chose the latter because, according to him, one could always become a philosopher later, but not a biologist.

The post yielded little income, and Bertalanffy faced continuing financial difficulties.

He applied for promotion to the status of associate professor, but funding from the Rockefeller Foundation enabled him to make a trip to Chicago in 1937 to work with Nicolas Rashevsky.

[6] Within a month of his return, he joined the Nazi Party, which facilitated his promotion to professor at the University of Vienna in 1940.

[6] During the Second World War, he linked his "organismic" philosophy of biology to the dominant Nazi ideology, principally that of the Führerprinzip.

[6] Following the defeat of Nazism, Bertalanffy found denazification problematic and left Vienna in 1948.

They had a son, Felix D. Bertalanffy (1926-1999), who was a professor at the University of Manitoba[8] and followed in his father's footsteps by making his profession in the field of cancer research.

Today, Bertalanffy is considered to be a founder and one of the principal authors of the interdisciplinary school of thought known as general systems theory, which was pioneered by Alexander Bogdanov.

His contributions went beyond biology, and extended into cybernetics, education, history, philosophy, psychiatry, psychology and sociology.

[10] The dynamic energy budget theory provides a mechanistic explanation of this model in the case of isomorphs that experience a constant food availability.

The inverse of the Bertalanffy growth rate appears to depend linearly on the ultimate length, when different food levels are compared.

The intercept relates to the maintenance costs, the slope to the rate at which reserve is mobilized for use by metabolism.

[13] In the late 1920s, the Soviet philosopher Alexander Bogdanov pioneered "Tektology", whom Johann Plenge referred to as the theory of "general systems".

GST defined new foundations and developments as a generalized theory of systems with applications to numerous areas of study, emphasizing holism over reductionism, organism over mechanism.