The soldier, general, and boy who broke Locke's theory of identity
John Locke argued you are identical only to whoever you remember being. Thomas Reid exposed a logical flaw: a boy is flogged; as an officer, he captures a flag and remembers the beating. As an old general, he remembers the battle, but has forgotten the flogging. Under Locke's rule, the general is the officer, and the officer is the boy, yet the general is not the boy. But in logic, if A equals B and B equals C, A must equal C.
Locke's Memory Criterion and the Nature of Selfhood
In the late seventeenth century, John Locke proposed an influential account of what makes a human being the same person over time. Rather than anchoring personal identity to an immaterial soul or a persistent physical body, Locke located it in consciousness. For Locke, a person remains the same individual across days, years, or decades to the extent that their consciousness reaches back to past thoughts and actions. If an individual can remember an earlier experience from the inside, conscious of having performed or witnessed it, they are identical to the person who had that experience.
This view was groundbreaking because it separated personhood from substance. A human body could change completely as cells and tissues renewed themselves, and speculative questions about the nature of an invisible spiritual substance could be set aside. What mattered for moral responsibility, legal accountability, and self-understanding was subjective continuity. To Locke, punishment and reward made sense only if the being standing in the present shared consciousness with the being who committed the deed in the past.
The Brave Officer and the Failure of Transitivity
In the eighteenth century, Scottish philosopher Thomas Reid challenged Locke's psychological account by demonstrating that it violated an elementary rule of logic. In his Essays on the Intellectual Powers of Man, Reid presented a thought experiment that has become known as the brave officer paradox. He asked his readers to consider a young boy who was flogged at school for robbing an orchard, an ambitious young officer who captured an enemy standard on the battlefield while still remembering the beating, and an aged general who remembered taking the standard but had completely forgotten the schoolboy flogging.
Under Locke's definition, the officer is identical to the boy because the officer directly remembers the flogging. Similarly, the elderly general is identical to the officer because the general vividly remembers capturing the enemy flag. However, because the general has forgotten the orchard incident entirely, Locke's criterion dictates that the general is not identical to the boy. This outcome directly contradicts the logical principle of the transitivity of identity: if A equals B, and B equals C, then A must necessarily equal C. By Locke's rule, the general is the officer, the officer is the boy, yet the general is not the boy, resulting in a formal logical contradiction.
Confusing the Evidence with the Fact
Reid did not stop at exposing the logical flaw; he diagnosed why Locke had fallen into it. Reid argued that Locke had fundamentally confused the evidence of personal identity with identity itself. Memory provides an individual with epistemological access to their past—it is the evidence that informs a person that they were the one who performed an action. But having evidence of an event is not the same thing as the event or the relation existing in reality.
Reid pointed out that memory necessarily presupposes personal identity rather than creating it. To truly remember performing an action, an individual must already have been the person who performed it. If personal identity were literally constituted by the act of remembering, it would imply that a past deed only belongs to an individual when they happen to turn their mind toward it. For Reid, claiming that memory creates personal identity is as absurd as claiming that seeing an object creates the object, or that a witness's testimony creates the crime.
The Scottish Common Sense Defense of the Self
Thomas Reid developed his critique as part of the Scottish School of Common Sense, a philosophical movement that resisted the skeptical conclusions of modern philosophy, particularly the skepticism of his contemporary David Hume. Philosophers within the empiricist tradition had embraced what Reid called the 'way of ideas'—the theory that the human mind does not perceive external objects or genuine substances directly, but only interacts with intermediate mental impressions, sensations, and representations.
Pushed to its extreme by Hume, this approach dissolved the enduring self into a loose 'bundle of perceptions' lacking any continuous underlying unity. Reid argued that such conclusions contradicted the foundational principles of human nature and common sense, which every sane person relies on in daily life. In Reid's view, the self is not a succession of fleeting thoughts or conscious links, but a simple, indivisible, and enduring substance. Because the self is indivisible, personal identity cannot exist in degrees or fragments; an individual cannot be partly the same person and partly someone else.
The Fallibility of Human Memory and Responsibility
Tying personal identity to continuous memory creates practical and moral dilemmas that Reid highlighted. Human memory is inherently fallible, selective, and interrupted by periods of sleep, unconsciousness, intoxication, or simple forgetfulness. If identity depends entirely on the unbroken thread of recollection, then whenever a person sleeps without dreaming, or simply forgets a mundane afternoon from three weeks prior, their continuity of existence is severed.
This vulnerability would have severe consequences for moral and legal responsibility. A person who completely forgot committing an offense due to trauma, drunkenness, or the passage of decades would, under strict Lockean rules, no longer be the person who committed the crime. Reid maintained that society rightly holds individuals accountable for actions they genuinely performed, even if memory fails them entirely. The underlying historical fact of agency remains intact regardless of the present contents of the agent's mind.
The Paradox's Enduring Philosophical Impact
Reid's objection forced philosophers to reconsider how psychological continuity could be defined without collapsing into logical incoherence. Later defenders of psychological accounts attempted to salvage Locke's core insight by moving from direct memory to overlapping chains of continuity. In these updated accounts, the general remains identical to the boy not because he directly recalls the boy's experience, but because there is an unbroken, overlapping chain of memories connecting the boy to the officer and the officer to the general.
Nevertheless, Reid's critique remains a foundational case study in analytic philosophy. It established that any coherent philosophical theory must conform to basic logical axioms, including transitivity, and warned against conflating our subjective awareness of a reality with the metaphysical nature of reality itself. By defending the indivisible self against fragmentation, Reid provided a lasting framework for debates about consciousness, personal identity, and the limits of empiricism.
Key takeaways
•Thomas Reid demonstrated that John Locke's memory theory of identity violates the logical transitivity of identity, creating an impossible contradiction where a general is both identical and non-identical to his childhood self.
•Reid argued that Locke confused the evidence of identity with its metaphysical foundation, pointing out that memory presupposes that a person already existed rather than bringing identity into existence.
•As the founder of the Scottish School of Common Sense, Reid defended the self as a continuous, simple, and indivisible substance that cannot be reduced to a shifting chain of mental states.
•The paradox forced subsequent philosophers to reformulate psychological theories of identity, shifting the focus from direct memory to overlapping chains of psychological continuity.