Zero was not always on the number scale. The concept of zero emerged from the the contemplation of void by the Buddhists. While the notion of emptiness has negative connotation according to the Western psychology, the Buddhists don’t identify emptiness to the concept of nothing. 2
The number zero was discovered or invented in India. (”Invented” implies that zero is a
human construction, while ”discovered” assumes that while the symbol is created by human, the concept existed without any human activity.) It appeared in the Bakhshali manuscript, denoted by a point. While symbols as placeholders were used earlier by the Babylonians and Mayans, this script seems to be the first, where the symbol represents ”nothing”. Zero as a number is the result of the Buddhists deep introspection. The manuscript is located in the University of Oxford’s Bodleian Libraries, and it was a big excitement among the historians of mathematics in 2017, when radiocarbon dating of the documents showed that zero appeared in the 3rd or 4th century, four-five hundreds years earlier, that it was assumed 3. Zero arrived to Europe only around 1200, when the Italian mathematician traveled back from North-Africa, and now the whole digital age is based on the difference between ”nothing” and ”something”.
Integrative studies in cognitive science combined human developmental psychology, animal cognition and neurophysiology, and the results suggested zero emerges through four stages: first, sensory ”nothing”, i.e. the lack of any stimulus; second, the categorical ”something”, still qualitative; third, nothing is characterized quantitatively by empty sets; and finally there is a transition from an empty set to the number zero. 4 Present day cognitive neuroscience investigates the neural mechanisms of representing empty sets and zero.
Zero and non-zero, nothing and something are basic categories in our digital age. So, we
should think three times (referring to another magical number), when we declare: ”my pain is zero”.
2 https://www.huffingtonpost.com/lewis-richmond/emptiness-most-misunderstood-word-in-buddhism_b_2769189.html; Kaplan, R: The Nothing that Is: A Natural History of Zero. Oxford Univ. Press, 2000; Amir D.
Aczel: Finding Zero: A Mathematician’s Odyssey to Uncover the Origins of Numbers. St. Martin’s Press, 2015.
3 see e.g. https://www.theguardian.com/science/2017/sep/14/much-ado-about-nothing-ancient-indian-text-contains-earliest-
4 Nieder A: Representing Something Out of Nothing: The Dawning of Zero. Trends in Cognitive Science,
20(830-842), 2016 Nov.