Paul Kammerer was a brilliant yet eccentric Viennese biologist. Beyond his highly controversial work on the inheritance of acquired characteristics (notably the midwife toad affair), he became passionately engaged early on in the observation of statistical anomalies.
For over twenty years, he spent hours seated on park benches in Vienna or in trams, frantically noting in a notebook all the strange recurrences of his daily life: the number of people passing by with a green umbrella, sequential ticket numbers, repeated surnames within a single day.
Kammerer's career was destroyed by a resounding scientific scandal in 1926. His specimens of toads (supposedly proving Lamarckian inheritance) were discovered to be falsified, with someone having injected India ink into their limbs.
Although it was never proven that Kammerer himself was the forger (some speculate a zealous assistant or a conspiracy), the dishonor was complete. A few weeks after the scandal was revealed in the journal Nature, Kammerer went to the woods of Schneeberg and took his own life with a bullet to the head.
Kammerer accumulated hundreds of direct observations, establishing precise typologies for what was then considered mere chance.
In 1919, Kammerer published the fruits of his empirical observations in 'Das Gesetz der Serie' (The Law of Series). He postulated the existence of an unknown natural force or principle, acting parallel to the force of gravity.
According to him, just as gravity groups physical matter in space, the force of 'seriality' groups similar events in time. It is a force of affinity. He described this as the 'imitation of the universe upon itself'. Things that resemble each other tend to occur together.
Unlike Jung, Kammerer's approach was entirely devoid of psychology, meaning, or mysticism. It was a purely physical theory. He sought a causal, material explanation (albeit unknown), where Jung would later see an acausal principle linked to the observer's consciousness.
Nevertheless, Kammerer's work (which Albert Einstein deemed 'original and by no means absurd') provided the empirical foundation upon which Jung began to contemplate synchronicity.
The foundational work published in 1919 where he presents his theory of a natural affinity force explaining coincidences.