RIP Jay Forrester  

Ugo Bardi at Cassandra's Legacy has a tribute to the recently departed Jay Forrester, the inventor of system dynamics, the modelling method used in "The Limits To Growth" - Jay Forrester: the man who saw the future.

Jay Wright Forrester (1918-2016) may have been the source of inspiration for Hari Seldon, a fictional character in Isaac Asimov's Foundation series. In Asimov's novels, Seldon develops "pyschohistoric equations" that allow him to predict the impending collapse of the Galactic Empire. In the real world, Forrester developed "system dynamics equations" that allowed him to predict the impending collapse of the modern human civilization. The predictions were ignored by the Imperial powers of both the fictional and the real universe.

Jay Forrester, one of the great minds of the 20th century, died at 98, a few days ago. His career was long and fruitful, and we can say that his work changed the intellectual story of humankind in various ways, in particular for the role he had in the birth of the Club of Rome's report "The Limits to Growth".

In 1969, Forrester was a faculty member of the MIT when he met Aurelio Peccei in Italy. At that time, Peccei had already founded the Club of Rome, whose members were worried about the limits to the natural resources that the Earth could provide. They were trying to understand what the consequences would have been for humankind. From what Peccei wrote, it seems clear that he was seeing the situation mostly in Malthusian terms; thinking that the human population would have been growing until reaching the resource limits, and then stay there, kept in check by famines and epidemics. The main concern of Peccei and of the Club of Rome was to avoid human suffering by ensuring a fair distribution of what was available.

The encounter with Forrester changed this vision in ways that, perhaps, neither Peccei nor any of the Club members would have imagined. In the 1960s, Forrester's models were already well advanced. Based on a completely new method of calculation that Forrester had dubbed "system dynamics," the models were able to take into account how the many variables of a complex system interacted with each other and changed in time.

The result was the study that the Club of Rome commissioned to Forrester and to his research group: simulate the future of humankind over a time range of more than a century, all the way to 2100. Forrester himself prepared a complete study with the title "World Dynamics" that was published in 1971. A group of Forrester's students and coworkers prepared a more extensive study titled "The Limits to Growth" that became a true intellectual revolution in 1972.