# Heinz von Foerster

Heinz von Foerster (né von Förster; November 13, 1911 – October 2, 2002) was an Austrian-American scientist combining physics and philosophy, and widely attributed as the originator of second-order cybernetics. He was twice a Guggenheim fellow (1956–57 and 1963–64) and also was a fellow of the American Association for the Advancement of Science, 1980. He is well known for his 1960 Doomsday equation formula published in Science predicting future population growth.
As a polymath, he wrote nearly two hundred professional papers, gaining renown in fields ranging from computer science and artificial intelligence to epistemology, and researched high-speed electronics and electro-optics switching devices as a physicist, and in biophysics, the study of memory and knowledge. He worked on cognition based on neurophysiology, mathematics, and philosophy and was called "one of the most consequential thinkers in the history of cybernetics". He came to the United States, and stayed after meeting with Warren Sturgis McCulloch, where he received funding from The Pentagon to establish the Biological Computer Laboratory, which built the first parallel computer, the Numa-Rete. Working with William Ross Ashby, one of the original Ratio Club members, and together with Warren McCulloch, Norbert Wiener, John von Neumann and Lawrence J. Fogel, Heinz von Foerster was an architect of cybernetics and one of the members of the Macy conferences, eventually becoming editor of its early proceedings alongside Hans-Lukas Teuber and Margaret Mead.

## Biography

Von Foerster was born in 1911 in Vienna, Austria-Hungary, as Heinz von Förster. His paternal grandfather was the Austrian architect Emil von Förster [de]. His maternal grandmother was Marie Lang, an Austrian feminist, theosophist, and publisher. He studied physics at the Technical University of Vienna and at the University of Breslau, where in 1944 he received a PhD in physics. His relatives included Ludwig Wittgenstein, Erwin Lang and Hugo von Hofmannsthal. Ludwig Förster was his great-grandfather. His Jewish roots did not cause him much trouble while he worked in radar laboratories during the Nazi era, as "he hid his ancestry with the help of an employer who chose not to press him for documents on his family."
He moved to the US in 1949 and worked at the University of Illinois at Urbana–Champaign, where he was a professor of electrical engineering from 1951 to 1975. He was also professor of biophysics (1962–1975) and director of the Biological Computer Laboratory (1958–1975). Additionally, in 1956–57 and 1963–64, he was a Guggenheim Fellow and also President of the Wenner-Gren-Foundation for anthropological research from 1963 to 1965.
He knew well and was in conversation with John von Neumann, Norbert Wiener, Humberto Maturana, Francisco Varela, Gordon Pask, Gregory Bateson, Lawrence J. Fogel and Margaret Mead, among many others. He influenced generations of students as a teacher and an inclusive, enthusiastic collaborator.
He died on October 2, 2002, in Pescadero, California.

## Work

Von Foerster was influenced by the Vienna Circle and Ludwig Wittgenstein. He worked in the field of cybernetics and is known as the inventor of second-order cybernetics. He made important contributions to constructivism. He is also known for his interest in computer music and magic.

### The electron tube laboratory

In 1949, von Foerster started work at the University of Illinois at Urbana–Champaign at the electron tube laboratory of the Electrical Engineering Department, where he succeeded Joseph Tykociński-Tykociner. With his students he developed many innovative devices, including ultra-high-frequency electronics
He also worked on mathematical models of population dynamics and in 1959 published a model now called the "von Foerster equation", which is derivable from the principles of constant aging and conservation of mass.
    ${\frac {\partial n}{\partial t}}+{\frac {\partial n}{\partial a}}=-m(a)n,$
where: n = n(t,a), t stands for time and a for age. m(a) is the death in function of the population age; n(t,a) is the population density in function of age.
When m(a) = 0, we have:
    ${\frac {\partial n}{\partial t}}=-{\frac {\partial n}{\partial a}}$
It relates that a population ages, and that fact is the only one that influences change in population density.
It is therefore a continuity equation; it can be solved using the method of characteristics. Another way is by similarity solution; and a third is a numerical approach such as finite differences.
The gross birth rate is given by the following boundary condition:
    $n(t,0)=\int _{0}^{\infty }b(a)n(t,a)\,dt,$
The solution is only unique given the initial conditions
    $n(0,a)=f(a),\,$
which states that the initial population distribution must be given; then it will evolve according to the partial differential equation.

### Biological Computer Laboratory

In 1958, he formed the Biological Computer Lab, studying similarities in cybernetic systems in biology and electronics.

### Macy conferences

He was the youngest member of the core group of the Macy conferences on Cybernetics and editor of the five volumes of Cybernetics (1949–1953), a series of conference transcripts that represent important foundational conversations in the field. It was von Foerster who suggested that Wiener's coinage "Cybernetics" be applied to this conference series, which had previously been called "Circular Causal and Feedback Mechanisms in Biological and Social Systems".

### Doomsday equation

A 1960 issue of Science magazine included an article by von Foerster and his colleagues, P. M. Mora and L. W. Amiot, proposing an equation representing the best fit to the historical data on the Earth's population available in 1958:
   Fifty years ago, Science published a study with the provocative title “Doomsday: Friday, 13 November, A.D. 2026”. It fitted world population during the previous two millennia with P = 179 × 10$^9$/(2026.9 − t)$^{0.99}$. This “quasi-hyperbolic” equation (hyperbolic having exponent 1.00 in the denominator) projected to infinite population in 2026—and to an imaginary one thereafter.
       —Taagepera, Rein. A world population growth model: Interaction with Earth's carrying capacity and technology in limited space Technological Forecasting and Social Change, v. 82, February 2014, pp. 34–41
In its simplified hyperbolic form (i.e. with the exponent in the denominator assumed to be 1.00), the doomsday equation reads as follows:
    $Population={\frac {179000000000}{2026.9-t}},$
where t is the number of a year of the Gregorian calendar.
For example, the doomsday equation (developed in 1958, when the Earth's population was 2,911,249,671) predicts a population of 5,986,622,074 for the beginning of the year 1997:
    ${\frac {179000000000}{2026.9-1997}}=5986622074.$
The actual figure was 5,924,787,816.
The doomsday equation is called so because it predicts that the number of people living on the planet Earth will become maximally positive by 13 November 2026 (von Foerster's 115th anniversary), and on the next moment will become negative.