Modern symbols
Symbols given new meaning by recent movements, science and culture, and the stories behind them.
The six symbols here each gained a new meaning in the twentieth or twenty-first century: a magician’s seal, a physicist’s thought experiment, a mathematical sign and a punctuation mark. Each page says who gave the symbol its new meaning, and when.
Magic and science
- SigilsA sigil is a drawn sign that magical practitioners believe carries power. In the old books of magic it is the seal of a named spirit or angel; since the artist Austin Osman Spare published his method in 1913, it is more often a monogram a practitioner makes from the letters of a written wish.
- Schrödinger’s catSchrödinger’s cat is a thought experiment the physicist Erwin Schrödinger published in 1935: a cat shut in a steel chamber that quantum mechanics, taken literally, would describe as alive and dead at once until someone looks. He offered it as a ridiculous case, to question the theory; it has since become a popular emblem for anything undecided.
Movements and awareness
- Infinity symbol (∞)∞ is the mathematical sign for infinity, a figure eight lying on its side. The English mathematician John Wallis introduced it in 1655, and why he chose the shape is disputed. It is also called the lemniscate, and outside mathematics it is carried on the Métis flag and by autistic and neurodiversity advocates.
- Autism infinity symbolThe gold infinity symbol is a sign autistic people use for autism: gold because its chemical symbol, Au, is the first two letters of “autism”. With the rainbow infinity of the wider neurodiversity movement, it is the symbol many autistic advocates choose in place of the older puzzle piece.
- Neurodiversity symbolThe rainbow infinity symbol is the sign of the neurodiversity movement, which holds that differences such as autism, ADHD and dyslexia are natural variations among people. Autistic advocates first used it in 2005; a gold version stands for autism in particular.
- Semicolon tattooA semicolon tattoo is the sign of Project Semicolon, a mental-health and suicide-prevention movement begun in the United States in 2013. A semicolon marks the place where a writer could have ended a sentence and chose not to; wearers use it to say that their life, like the sentence, isn’t over.
The sigil
A sigil was first a seal: the word comes from Latin sigilla, “statuettes, little images, seal”, and in the Goetia each spirit has one: “This is his seal.” In The Book of Pleasure (1913), Austin Osman Spare turned the sigil into a monogram a practitioner makes from the letters of their own wish. Chaos magic took up his idea; its first order, the Illuminates of Thanateros, was founded in 1978.
Schrödinger’s cat
Schrödinger set out the cat in 1935 as one of the “quite ridiculous cases” that follow if the theory’s “blurred model” is taken for reality. Paul Halpern, writing for NOVA, says the cat was scarcely mentioned until after Schrödinger’s death in 1961. It became a classroom example first, and later what Halpern calls “a popular emblem for ambiguity”.
The infinity sign, from Wallis to Autistic Pride
John Wallis first used ∞ in 1655. Why he chose it is disputed: MacTutor says for a curve that can be traced infinitely often, while Jeff Miller’s history gives the Roman sign for 1,000 and the Greek omega as possible sources. In 2005 the forum Aspies for Freedom began Autistic Pride Day. The sources disagree on the colours: Aimee Grant (The Conversation) gives the rainbow infinity to the neurodivergent community and gold, from Au, to autism; the Autistic Empire describes the Autistic Pride flag as “a rainbow infinity symbol on a gold field”, AutismBC as a gold infinity on a rainbow. Grant writes that many autistic adults find the older puzzle piece offensive. The infinity symbol, autism infinity symbol and neurodiversity symbol pages give each reading.
The semicolon
In April 2013 Amy Bleuel asked anyone who had struggled with mental illness to draw a semicolon on their wrist and post a photo. Project Semicolon, a nonprofit since 2015, explains the mark: “A semicolon is used when an author could’ve chosen to end their sentence, but chose not to. The author is you, and the sentence is your life.” In the United States, the 988 Suicide & Crisis Lifeline is free and confidential: call, text or chat 988, at any hour.
Sources
- sigil (n.), Douglas Harper, Online Etymology Dictionary
- Lemegeton Clavicula Salomonis Rex, Part 1: Goetia, Digital edition by Joseph H. Peterson, 1999, updated 2026; transcribed from British Library Sloane MS 3825, Esoteric Archives, Introduction; spirits 1 and 3
- The Book of Pleasure (Self-Love): The Psychology of Ecstasy, by Austin Osman Spare, First published London, 1913; sacred-texts.com transcription (Internet Archive copy, January 2025), sacred-texts.com, Chapter “Sigils. Belief with protection”
- The Book of Pleasure, Publisher’s page for its edition of Spare’s book, Jerusalem Press
- Illuminates of Thanateros (IOT), From John Michael Greer, The Element Encyclopedia of Secret Societies (2006), Occult World
- The Present Situation in Quantum Mechanics: A Translation of Schrödinger’s “Cat Paradox” Paper, John D. Trimmer, Proceedings of the American Philosophical Society 124 (5), 1980, pp. 323–338, American Philosophical Society (copy hosted by the Universidade Estadual de Campinas), Introduction and §5
- Schrödinger’s Cat Lives On (Or Not) at the Age of 80, Paul Halpern, 10 November 2015, NOVA, PBS
- Infinity, J. J. O’Connor and E. F. Robertson, MacTutor History of Mathematics, University of St Andrews
- Earliest Uses of Symbols of Calculus, Jeff Miller, Earliest Uses of Various Mathematical Symbols, MacTutor History of Mathematics, University of St Andrews, “Infinity”
- Autistic Pride, Autistic Empire
- Understanding Red and Gold: Colours of Autism Acceptance and Pride, AutismBC
- Why the autism jigsaw puzzle piece is such a problematic symbol, Aimee Grant, Swansea University, 10 April 2025, The Conversation
- ‘And your story will live on’: Remembering Amy Bleuel, mental health advocate and founder of Project Semicolon, Colby Itkowitz, 30 March 2017, The Washington Post
- Our History, Project Semicolon (Internet Archive copy, 18 April 2025; the organisation’s site was offline when checked in September 2026), Project Semicolon
- 988 Suicide & Crisis Lifeline: Get Help, 988 Suicide & Crisis Lifeline
- 988 Suicide & Crisis Lifeline, Substance Abuse and Mental Health Services Administration (SAMHSA)
Last reviewed September 30, 2026 by Rory Hansen. How we research