Sigmund Freud

Sigmund Freud is presented not through a biographical narrative but as a continuing point of reference in the effort to connect subjective experience with the brain. His account of the ego and the unconscious gives Robin Carhart-Harris a conceptual vocabulary for questions that neuroscience has difficulty answering, and later serves as a striking comparison for hypotheses about the default mode network. The book’s treatment keeps that comparison in view without treating psychoanalytic ideas and brain-imaging results as interchangeable kinds of evidence.

The Ego and the Problem of Consciousness

Freud’s most direct appearance comes in a discussion of consciousness and the self. The book recalls his claim that people are supremely certain of the feeling of their own self, or ego. That certainty sits uneasily beside a scientific problem: subjective experience has no straightforward outward proof. A person can report experience, but the first-person quality of that experience is not itself an observable object in the way a change in sensory response might be. Freud’s formulation therefore sharpens the puzzle rather than resolving it. The self feels most immediate to the person who has it, while remaining difficult to establish from outside.

This tension gives Freud’s reference a role beyond a historical name-check. The question is not merely whether a brain can be measured, but how measurements of physical structures and chemical activity could explain what experience feels like. The book distinguishes ordinary sensory responsiveness from consciousness in the fuller sense of having a self that experiences. Freud’s observation draws attention to the gap between the apparent certainty of that self and the difficulty of making it an object of scientific knowledge. In this account, his work is relevant because it puts the ego at the center of a problem that experimental neuroscience can approach without yet settling.

A Psychoanalytic Route Toward Neuroscience

Carhart-Harris’s early interest in Freud helps explain the unusual route by which the book’s brain-imaging research took shape. He studied psychoanalysis and was fascinated by its theories, but frustrated by the limited rigor and methods available for investigating the unconscious, which psychoanalysis treated as central. He wondered whether a drug might provide another way to approach that territory. His professor directed him to Stanislav Grof’s work on the human unconscious; reading it became a decisive influence on the course Carhart-Harris wanted to pursue.

Carhart-Harris’s plan was to bring psychedelic drugs and contemporary brain-imaging technology to questions associated with psychoanalysis. Freud’s importance here is both inspiration and contrast: the psychoanalytic account supplied questions and concepts, but Carhart-Harris wanted a firmer scientific basis for exploring them. The book presents this as an attempt to investigate the unconscious through methods that could observe changes in the brain as they unfolded, rather than relying only on dreams and free association. The ambition was not simply to repeat Freud’s theory in neuroscientific language, but to build a way of testing questions that psychoanalysis had made important.

Repression and the Default Mode Network

The comparison becomes more specific in the discussion of the default mode network. The book describes this network as exerting an inhibitory influence on other areas, including limbic regions involved in emotion and memory. David Nutt characterizes the network as a neural correlate for repression; Carhart-Harris, in turn, hypothesizes that when its usual influence recedes, other mental systems are released from restraint. Brain scans during psychedelic states show increased activity in several regions, including limbic areas, as reflected in blood flow and oxygen consumption.

The analogy to Freud is illuminating but carefully bounded. Freud’s ego was conceived as keeping unruly unconscious forces in check; the account compares that model with a brain network that may constrain other kinds of activity. On this hypothesis, a temporary reduction in that constraint could allow emotions, memories, and sometimes long-buried childhood traumas to enter awareness. The scans provide evidence of altered brain activity, while the language of repression offers an interpretation of what those changes might mean psychologically. The book does not collapse one into the other: the proposed neural correspondence makes psychoanalytic questions newly investigable, but does not by itself demonstrate Freud’s theory.

Ego Development and Psychedelic Experience

Freud also informs Carhart-Harris’s account of how forms of consciousness might differ. In the model presented in the book, an early, more emotionally influenced mode of cognition precedes the development of the default mode network and a coherent ego. The later mode is more closely oriented toward representing the world and reducing uncertainty. Carhart-Harris borrows from Freud in describing this as a movement from a more primitive, wish- and fear-shaped consciousness toward a reality-bound one governed by the ego. This is the book’s account of Carhart-Harris’s framework, not a claim that brain imaging has independently established Freud’s developmental theory.

Within that framework, psychedelic states may quiet the default mode network and loosen the ego’s ordinary dominance, allowing less regulated material to become noticeable. Carhart-Harris interprets the resulting loss of self and sense of oneness as a return to an earlier psychological condition, compared with the infant’s lack of a settled sense of itself as a separate individual. This reading places a limit on more expansive interpretations of mystical experience: such experiences may feel as if they disclose a reality beyond the individual, but Carhart-Harris does not take that feeling as proof that consciousness exists independently of the brain. Freud’s concepts thus support both a research program and a skeptical interpretation of what that research encounters. The ego is at once a constraint that may be loosened and, in this account, an achievement of human development that psychedelic experience temporarily reverses.