Alexander Grothendieck

This morning I read a Quanta Magazine article about a mathematician named Alexander Grothendieck titled How Alexander Grothendieck Revolutionized 20th Century Mathematics. I'd never heard of him. The article focuses on his mathematical contributions but says very little about his eccentric personal life. I asked Gemini the following:

Grothenddieck was a famous 20th century mathematician. Find out all you can about his personal life as opposed to his contributions to Mathematics. In particular what were his reasons for living as a recluse in the final years of his life. He fathered five children so presumably he turned his back on his family. 

Figure 1

Figure 1, taken from the Quanta Magazine article carries the following caption:

Grothendieck, seen here in 1954, was fascinated by hidden geometric structure. “If there is one thing in mathematics which fascinates me more than any other (and undoubtedly always has), it is neither ‘number’ nor ‘size,’ but invariably shape,” he wrote.

Here was Gemini's  response to my query:

You are entirely correct in your presumption. Despite fathering five children, Alexander Grothendieck was notoriously detached from his family and eventually abandoned those relationships completely. His colleague and biographer Pierre Cartier once noted that Grothendieck was "as absent a father to them as his own father was to him."

A Chaotic Family Life

Grothendieck's personal life was highly unstable, and his five children were born to three different women:

• Serge: Born to his landlady in Nancy during his early university years. Grothendieck later unsuccessfully sued for custody.
  
  
• Johanna (1959), Alexander (1961), and Mathieu (1965): Born to his wife, Mireille Dufour.
  
  
• A fifth child: Born to Justine Skalba, with whom he lived in a radical pacifist commune in the early 1970s.

Ultimately, his intense, manic obsession with his work—and later his extreme political and mystical beliefs—left almost no room for traditional familial bonds. He eventually severed all ties with his children and his past.

Early Trauma and a Stateless Youth

To understand his eventual rejection of society, it is crucial to look at his deeply traumatic upbringing.

Born in Berlin in 1928, his parents were radical anarchists. His father, a Russian Jew, was handed over to the Nazis by the French Vichy government and murdered in Auschwitz. Alexander and his mother were interned in French refugee and concentration camps (such as Rieucros) during World War II, and he spent years hiding in the woods from authorities.

Grothendieck was technically stateless for most of his life, only taking French citizenship in 1971. This early exposure to the brutality of the state instilled in him a permanent, uncompromising distrust of institutions, authority, and eventually, the scientific establishment itself.

Grothendieck lived the final decades of his life
as a recluse in the French countryside.
This 2013 photo was taken a year before his death.

Reasons for His Final Retreat

Grothendieck did not become a recluse overnight. His withdrawal was a gradual, decades-long process fueled by profound moral convictions, deep disillusionment, and an increasingly fragile psychological state.

• The 1970 Fracture: The major turning point occurred in 1970 when he discovered that his prestigious research home, the Institut des Hautes Études Scientifiques (IHÉS), received a small fraction of its funding from the French military. A strict pacifist, Grothendieck resigned immediately.
  
  
• Radical Pacifism: He shifted his immense intellectual focus from mathematics to environmentalism and anti-militarism, founding a group called Survivre et Vivre (Survive and Live). He became convinced that mainstream science was inextricably linked to militarism and global destruction.
  
  
• Rejection of the Establishment: By the 1980s, he felt completely alienated from his peers. In 1988, he famously refused the highly prestigious Crafoord Prize (and its $250,000 award). He wrote a scathing public letter to the Swedish Academy declaring that the scientific world had become ethically compromised and spiritually dead.
  
  
• Descent into Mysticism: In his later years, his writings became highly focused on spirituality, the apocalypse, and mystical visions. He wrote thousands of pages of personal, philosophical reflections—most notably the massive Récoltes et Semailles (Reaping and Sowing)—which blended brilliant self-analysis with bitter grievances against his former friends and colleagues.

In 1991, he completely vanished from public life. He moved to Lasserre, a tiny village in the French Pyrenees, and legally demanded that all of his unpublished works be destroyed. For the last 23 years of his life, he refused visitors, ignored letters, and lived a fiercely ascetic, solitary existence until his death in 2014 at the age of 86.

The MacTutor has a quite detailed biography about Grothendieck. Within this biography, there are links to even more detailed information about him with this link being especially informative.