1651
Thomas Hobbes
Hobbes, Thomas. Leviathan. London: Andrew Crooke, 1651.
Preserves the older social sense of being conscious together, then describes the inward metaphorical movement toward secret facts and secret thoughts.
Sources
The act of checking
Turabian 9th edition, Notes-Bibliography. Claims in this work are not equal. Primary text, documented fact, scholarly interpretation, project reading, and open question are different kinds of force.
Primary sources
13
Texts the walk reads from. Locke, Cudworth, Plotinus, the New Testament, and the rest of the primary shelf.
Scholarship
29
Historians and philosophers of the word. The checking, not the primary.
Primary sources
1678
Ralph Cudworth
Cudworth, Ralph. The True Intellectual System of the Universe. London: Richard Royston, 1678.
Translates Plotinus's synaisthēsis as con-sense or consciousness. Distinguishes grades of awareness and allows mental activity that is not fully conscious.
Plastic natures operate without express consciousness.
1690
John Locke
Locke, John. An Essay Concerning Humane Understanding, first edition. 1st ed.. London: Thomas Basset, 1690.
Title page dated 1690. Circulating by late 1689.
Printed title uses Humane. Already contains Locke's account of consciousness as perception of what passes in one's own mind.
Does not yet contain Book II, Chapter XXVII.
1694
John Locke
Locke, John. An Essay Concerning Humane Understanding, second edition. 2nd ed.. London: Awnsham and John Churchill, 1694.
Adds the major treatment of persons and personal identity after encouragement from William Molyneux. Person is a forensic term.
Identity of the person is tied to consciousness, not simply to body or soul. This chapter is 1694, not 1690.
c. 250–270
Plotinus
Plotinus. Enneads. c. 250–270.
Synaisthēsis, co-perception or inner sense of the soul. Source material later received by Cudworth.
Plotinus did not possess the modern English concept.
c. 1020s
Avicenna (Ibn Sīnā)
Avicenna (Ibn Sīnā). Kitāb al-Shifāʾ, Kitāb al-Nafs. c. 1020s.
The flying or suspended person thought experiment. Argues that the soul can affirm its own existence without affirming a body.
Embedded in Avicenna's account of nafs, not a Cartesian proof.
c. 397–400
Augustine of Hippo
Hippo, Augustine of. Confessions. c. 397–400.
Memory as a vast inner place. Distinct from the moral inner witness of syneidēsis and conscientia.
Cited here as a limit: a palace is not a court. Not a claim that Augustine invented the inner self.
1890
William James
James, William. The Principles of Psychology. New York: Henry Holt, 1890.
Consciousness as personal, constantly changing, and sensibly continuous. Names Heraclitus: we never descend twice into the same stream.
The stream metaphor is an account of how thought presents itself, not a claim to have invented subjective experience.
c. late sixth to early fifth century BCE
Heraclitus of Ephesus
Heraclitus of Ephesus. Fragments on the river. c. late sixth to early fifth century BCE.
You cannot step twice into the same river. A claim about becoming.
James cites him. That is not a psychology of consciousness, and not a line of descent.
written 1704, published 1765
G. W. Leibniz
Leibniz, G. W.. Nouveaux essais sur l'entendement humain. 1765.
Minute perceptions of which we are unaware, illustrated by the roar of the sea. Distinguishes perception from apperception.
c. 414
Jerome
Jerome. Commentary on Ezekiel. c. 414.
A Latin treatment of the spark of conscience later read as synderesis. Important for the medieval conscience tradition, not a theory of phenomenal consciousness.
c. 57
Paul the apostle
Paul the apostle. Letter to the Romans. c. 57.
Conscience bearing witness, thoughts accusing or defending. A major transmission path for conscientia in Christian moral psychology.
1731
Ralph Cudworth
Cudworth, Ralph. A Treatise concerning Eternal and Immutable Morality. London: James and John Knapton, 1731.
Published posthumously. The mirror and eye argument is 1731, not 1678.
A watch is held before a mirror and a living eye. The mind superadded apprehends relations (cause, effect, means, end, whole, part) that sense and the mirror do not.
Scholarship
April 1918
May Sinclair
Sinclair, May. “The Novels of Dorothy Richardson.” The Egoist. April 1918.
First applies stream of consciousness to a work of literature, taking the metaphor from psychology. A method of fiction, not a proof of James's description.
1990
Mihaly Csikszentmihalyi
Csikszentmihalyi, Mihaly. Flow: The Psychology of Optimal Experience. New York: Harper and Row, 1990.
Flow as absorption in which self-consciousness recedes. A later water.
Not James's stream restated. In flow, the watcher of the stream often goes quiet.
substantive revision, consulted 2026
Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy. “Seventeenth-Century Theories of Consciousness.” Stanford Encyclopedia of Philosophy. substantive revision, consulted 2026.
Spine for the linguistic transition, Cudworth, Hobbes, Locke, and grades of awareness.
consulted 2026
Sarah Hutton
Hutton, Sarah. “Ralph Cudworth.” Stanford Encyclopedia of Philosophy. consulted 2026.
Cudworth's con-sense, plastic natures, free will, and moral philosophy. Warns against treating the published System as a complete ethics.
consulted 2026
Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy. “Locke on Personal Identity.” Stanford Encyclopedia of Philosophy. consulted 2026.
Dates the identity chapter to the 1694 second edition. Distinguishes consciousness from a simple memory theory.
consulted 2026
Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy. “Medieval Theories of Conscience.” Stanford Encyclopedia of Philosophy. consulted 2026.
Synderesis and conscientia. Infallible first principles versus fallible application.
consulted 2026
Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy. “Mind (Heart-Mind) in Chinese Philosophy.” Stanford Encyclopedia of Philosophy. consulted 2026.
Xin is not the ancient Chinese word for consciousness. It partitions thinking, affect, desire, and ethical cultivation together.
consulted 2026
Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy. “Mind in Indian Buddhist Philosophy.” Stanford Encyclopedia of Philosophy. consulted 2026.
Citta, manas, and vijñāna are not one concept. Traditions disagree about self, momentariness, and reflexive awareness.
consulted 2026
Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy. “Ibn Sina [Avicenna] / Arabic and Islamic Psychology.” Stanford Encyclopedia of Philosophy. consulted 2026.
Flying man in its own philosophical context. Caution against proto-Cartesian readings.
2011
Udo Thiel
Thiel, Udo. The Early Modern Subject. Oxford: Oxford University Press, 2011.
The making of the early modern self. Essential on conscientia, consciousness, and the seventeenth-century subject.
2016
Shelley Weinberg
Weinberg, Shelley. Consciousness in Locke. Oxford: Oxford University Press, 2016.
Consciousness in Locke as non-evaluative self-referential awareness internal to perception, not identical with memory or reflection.
2021
Ruth Boeker
Boeker, Ruth. Locke on Persons and Personal Identity. Oxford: Oxford University Press, 2021.
Personhood, moral accountability, and why Locke's theory is not a simple memory criterion.
2019–2022
Matthew Leisinger
Leisinger, Matthew. “Essays on Cudworthian consciousness and agency.” 2019–2022.
Cudworth's grades of consciousness, the hegemonikon, and the work the word was doing in a theory of agency.
2025
Cogitate Consortium (Ferrante et al.)
Cogitate Consortium (Ferrante et al.). “Adversarial testing of global neuronal workspace and integrated information theories of consciousness.” Nature 642. 2025.
Preregistered adversarial collaboration. Some predictions of both IIT and GNWT were supported; important claims of both were substantially challenged.
Neither theory was simply disproved.
2024
Sarah Hutton
Hutton, Sarah. “Ralph Cudworth.” Stanford Encyclopedia of Philosophy. 2024.
Dates the watch illustration to TEIM 85–6 in modern pagination. Distinguishes the 1678 System from the posthumous Treatise.
5 October 2019
Elon Musk
Elon Musk. “Reply on the meaning of life.” X, 5 October 2019.
Asked what the meaning of life is. Answered: to understand the nature of consciousness.
Contemporary public statement, not a scientific paper. The Meaning of Life keeps this sentence.
28 October 2021
Elon Musk
Elon Musk. “Preserve the light of consciousness.” X, 28 October 2021.
Public wording: use of resources to get humanity to Mars and preserve the light of consciousness. Mission language, not a scientific term.
April 2022
Elon Musk
Musk, Elon. TED interview, Chris Anderson. April 2022.
Describes expanding the scope and scale of consciousness, biological and digital, as a driving philosophy. Nearby jokes are jokes.
They are not evidence for the philosophy.
2023
Elon Musk
Musk, Elon. Lex Fridman Podcast 400. 2023.
Asks what consciousness is, how arrangements of atoms produce thought and feeling, whether there may be something more that some people call a soul, whether everything or nothing might be conscious.
Speculation and open question, not settled neuroscience.
29 August 2024, 05:10:14 GMT
Elon Musk
Elon Musk. “Eyes are the window to the soul.” X, 29 August 2024, 05:10:14 GMT.
Exact words: Eyes are the window to the soul. Posted in reply to Why do his eyes look evil?
A proverbial sentence in a reply thread. Not a treatise.
Not a restatement of Cudworth.
current public site
SpaceX
SpaceX. Mission language: extend the light of consciousness. current public site.
Institutional mission language about making life multiplanetary and extending the light of consciousness to the stars. Not scientific consensus.
Not a definition of consciousness.
encounter 2023; recording first broadcast 29 October 2017
The Book of 42
The Book of 42. The Story Before the Story. encounter 2023; recording first broadcast 29 October 2017.
Living memoir. A recorded 60 Minutes Australia interview encountered on X.
His eyes. His words.
Tears she could not account for. The Book does not claim access to his private interior, nor that the recorded gaze was directed at her.
11 March 2015
Elon Musk
Musk, Elon. On the meaning of life. 11 March 2015.
Published interview. Expand the scope and scale of consciousness and knowledge.
Early public philosophy, not a paper.
17 September 2024
Elon Musk
Elon Musk. “Silicon or carbon.” X, 17 September 2024.
Exact words: We should expand the scope and scale of consciousness, whether silicon or carbon, to understand the universe.
22 January 2026
Elon Musk
Elon Musk. “Protect the light of consciousness.” X, 22 January 2026.
Reply: Protect the light of consciousness. Quotes a spoken SpaceX purpose: a tiny candle in a vast darkness that could easily go out.
15 June 2026
Elon Musk
Elon Musk. “Extend the light of consciousness to the stars.” X, 15 June 2026.
Exact words: Make our Sun sentient to understand the Universe and extend the light of consciousness to the stars. Mission language, not a definition.
28 July 2026
Elon Musk
Elon Musk. “The tiny candle.” X, 28 July 2026.
Exact words: Never forget how fragile the tiny candle of consciousness is.
13 August 2026
Elon Musk
Elon Musk. “Propagation of consciousness to the stars.” X, 13 August 2026.
Asked his motivation. Exact words: The mission is advancement of civilization and propagation of consciousness to the stars.
2023
Walter Isaacson
Isaacson, Walter. Elon Musk. New York: Simon & Schuster, 2023. Kindle.
Isaacson, biographer of Franklin, Einstein, Leonardo, and Jobs, writes that Musk spoke with the conviction of a prophet about nurturing the flame of human consciousness, fathoming the universe, and saving the planet.
He first thought it role-playing. Then he came to believe the sense of mission was part of what drove him.
Biographer's wording. Nurture is Isaacson's verb.