Philosophy and the Mind Sciences
December 30, 2020
Jakob Hohwy, Anil K. Seth
162 citations
The search for the neural correlates of consciousness needs a systematic, principled foundation to give putative correlates greater predictive and explanatory value. The predictive processing framework for brain function is proposed as a promising candidate because it addresses three general challenges to identifying neural correlates and satisfies two constraints common to many theories of consciousness. Implementing the search through this lens can yield detailed, systematic mappings between neural substrates and phenomenological structure. The framework, precisely because it is not itself a theory of consciousness, has significant potential for advancing the neuroscience of consciousness.
Philosophy and the Mind Sciences
March 24, 2020
Thomas Metzinger
133 citations
This paper proposes that the simplest form of conscious experience, termed "minimal phenomenal experience" (MPE), can be identified with the state of "pure awareness" reported in meditation. The authors derive six semantic constraints from existing literature and analyze sixteen phenomenological case studies to develop this concept. They hypothesize that pure awareness corresponds to a Bayesian predictive model of tonic alertness, which on an abstract level represents an unpartitioned epistemic space. This offers a minimal model explanation for conscious experience, grounding it in predictive processing theory.
Philosophy and the Mind Sciences
December 30, 2020
C. Klein, J. Hohwy, T. Bayne
54 citations
The search for neural correlates of consciousness (NCCs) is a central framework in consciousness science, often praised for its metaphysical neutrality. However, this framework implicitly assumes a specific model of consciousness—the Lite-Brite model—whose plausibility is an open question, making the NCC framework structurally biased. As an alternative, the authors propose a Difference-Maker framework that searches for difference makers of consciousness (DMCs) instead of mere correlates. Drawing on interventionist ideas in philosophy of science, they argue that shifting to DMCs would alter both experimental practice and how existing results are interpreted, offering a more neutral and productive approach.
Philosophy and the Mind Sciences
March 24, 2020
George Deane
48 citations
Psychedelic drugs like psilocybin, LSD, and DMT can profoundly alter experience, sometimes dissolving the sense of being a self—a phenomenon known as ego-dissolution. This paper explains such experiences using active inference, a theory from cognitive science. The self is described as a model built by the brain over time to guide an organism toward stability. Psychedelics lower the precision of high-level expectations, causing the brain to learn too quickly from new sensations. This relaxation of deep assumptions collapses the brain's sense of time and self, leading to a loss of ordinary selfhood. The account may illuminate both normal self-consciousness and its disruptions in conditions like psychosis, autism, depression, and dissociative disorders.
Philosophy and the Mind Sciences
March 24, 2020
Raphaël Millière
47 citations
Some states of consciousness may lack self-consciousness entirely. The author distinguishes six common notions of self-consciousness and argues that none is necessary for consciousness, because for each there exist conscious states where it is plausibly absent. Such states are at least partially selfless. Preliminary empirical evidence suggests some conscious states may lack all six forms, making them totally selfless—lacking every way one could be self-conscious. The author addresses four objections to the possibility and reportability of such totally selfless states.
Philosophy and the Mind Sciences
March 24, 2020
Chris Letheby
18 citations
The paper challenges the widely held view that phenomenal consciousness always requires some form of self-consciousness, a principle called the subjectivity principle (SP). Previous defenses of SP argued that mental states lacking self-consciousness, such as inserted thoughts in schizophrenia or depersonalization experiences, are not genuinely conscious. The author presents ego-dissolution experiences induced by fast-acting serotonergic psychedelics as counterexamples that are both phenomenally conscious and entirely selfless. The paper then critiques the concept of "for-me-ness," a proposed minimal form of self-awareness, by posing a dilemma: if for-me-ness includes an experiential component, it is absent in these psychedelic states; if it does not, the definition undermines its proponents' claims and concedes that conscious states can lack self-consciousness. The conclusion reflects on the intuitive appeal of SP in light of altered-state evidence.
Philosophy and the Mind Sciences
January 25, 2022
9 citations
A commentary argues that Chris Letheby's defense of psychedelic therapy insufficiently supports the claim that insights about the self are epistemically superior to those about the external world. The author contends that a key underexplored element is the capacity of self-related beliefs to become self-fulfilling prophecies. Recognizing the psychedelic experience and subsequent integration as opportunities not only to apprehend facts about the self but also to actively shape and redetermine those facts is crucial for understanding the epistemic differences between insights about the self and the external world.
Philosophy and the Mind Sciences
April 19, 2022
Sarah Hoffman
8 citations
Letheby's naturalistic theory of psychedelic therapy holds that the therapeutic power of psychedelics stems from enabling individuals to discover the contingency, mutability, and simulatory nature of their identity and habitual modes of attention. While the general shape of this project is persuasive and the claim that successful therapy involves changes to the self seems hard to object to, the role of affect in psychedelic therapy is insufficiently explored. A comparison with MDMA-assisted therapy indicates that Letheby's reliance on a particular conceptualization of ego dissolution experiences requires further explanation and justification.
Philosophy and the Mind Sciences
April 19, 2022
Sascha Benjamin Fink
7 citations
This philosophical commentary argues that while psychedelics can trigger processes of discovery, they rarely contribute directly to justification or epistemic success—truth, veridicality, aptness, or skillfulness—which are essential for a mental state to count as knowledge. The heavy epistemic work that turns a mental state into knowledge remains largely independent of psychedelic influence. However, the mechanisms Chris Letheby associates with psychedelics do provide crucial epistemic benefits when linked to understanding, offering a broader picture that includes cases where truth or justification is absent.
Philosophy and the Mind Sciences
April 19, 2022
Joshua M. Martin, Philipp Sterzer
7 citations
Psychedelics may help treat mental health conditions by changing how people think about themselves, but the context in which they are taken plays a crucial role. A commentary on Chris Letheby's 'Philosophy of Psychedelics' argues that a person's mindset and physical surroundings during a psychedelic experience shape which new self-conceptions they discover. This aligns with the REBUS model, where relaxing strong prior beliefs makes the brain more sensitive to incoming sensory information. A supportive environment and positive state of mind make beneficial changes in self-understanding and long-term well-being more likely. This view largely agrees with Letheby but questions his idea that psychedelics create a 'level cognitive playing field' where all self-related hypotheses are equally probable.
Philosophy and the Mind Sciences
April 19, 2022
Chris Letheby
6 citations
The author defends two central claims from their book Philosophy of Psychedelics: that psychedelic therapy works mainly by altering mental representations of the self, and that it yields epistemic benefits compatible with a naturalistic worldview. In response to commentaries, the author agrees with some supplementary mechanistic points from Hoffman and from Martin and Sterzer, while offering qualifications. The author also engages with challenges from Lyon, Farrenikova, and Colombo, defending core commitments. On epistemology, the author endorses connections to agency-first epistemology and self know-how from Bortolotti and Murphy-Hollies, and engages with Caporuscio's concept of self-shaping, again with qualifications. Finally, the author is sympathetic to Fink's proposal that the main epistemic benefit is increased understanding, but criticizes arguments for Psychedelic Justification Impossibilism.
Philosophy and the Mind Sciences
April 19, 2022
Matteo Colombo
6 citations
A commentary argues that Letheby's use of Predictive Processing to explain psychedelic therapy may lack genuine explanatory power, making his account unwarranted. The author motivates this concern and sketches an alternative interpretation of psychedelic therapy within the Reinforcement Learning framework.
Philosophy and the Mind Sciences
December 10, 2024
Adriana Alcaraz-Sánchez
5 citations
A new multidimensional framework introduces five phenomenological dimensions—Richness of the Content, Bodily-Awareness, Passage of Time, Attentional Focus, and Self-Revelation—to systematically study altered states of consciousness that appear contentless or objectless. Drawing on empirical research, the framework provides precise scientific terminology for operationalizing and adapting these experiences for future work. A case study applies the framework to clear light sleep, a state of pure awareness reported in Indo-Tibetan Buddhist traditions that has drawn attention in analytic philosophy of mind. The framework situates clear light sleep and other associated states as regions within a multidimensional state space, clarifying their relationships and characterizations.
Philosophy and the Mind Sciences
April 19, 2022
A. Lyon, Anya Farennikova
5 citations
The effectiveness of psychedelic psychotherapy may depend on specific changes in how people experience their own thoughts and perceptions, not just on the brain's neural disorganization. One prominent theory attributes therapeutic benefits to increased 'phenomenal opacity'—the sense that mental contents are constructed rather than direct reflections of reality. However, this paper argues that such accounts overlook the role of 'radically transparent' experiences, where perceptions feel vividly real and immediate. The authors describe common shifts toward phenomenal transparency during psychedelic sessions and contend that these experiences can also drive psychotherapeutic transformation. This alternative view suggests new directions for empirical research on attention and phenomenology in psychedelic treatment.
Philosophy and the Mind Sciences
April 19, 2022
Lisa Bortolotti, Kathleen Murphy-Hollies
4 citations
This paper examines the epistemological issues raised by psychedelic drugs as discussed in Letheby's book, arguing that his analysis requires an agency-first approach to epistemic evaluation. In this view, epistemic evaluation focuses on identifying the skills agents need to acquire to pursue and fulfill their epistemic goals.
Philosophy and the Mind Sciences
April 19, 2022
Chris Letheby
3 citations
A book-length philosophical examination of classic psychedelic drugs like psilocybin and LSD addresses the Comforting Delusion Objection—the concern that psychedelic therapy relies on inducing non-naturalistic metaphysical beliefs, making it epistemically and ethically problematic. The book reviews evidence for therapeutic efficacy and argues that psychedelics work not by neuroplasticity alone or by inducing supernatural ideations, but by altering mental representations of the self. Drawing on predictive processing theory and the self-binding theory of self-representation, it proposes a speculative account of this mechanism. The final chapters argue that psychedelic therapy can yield epistemic and spiritual benefits compatible with a naturalistic worldview.
Philosophy and the Mind Sciences
May 27, 2026
Edmundo Lopez-Sola, Roser Sanchez-Todo, Jakub Vohryzek et al.
1 citation
A computational framework rooted in algorithmic information theory, the algorithmic agent model, is used to investigate the phenomenon of pure awareness central to contemplative traditions. The framework proposes that agents build compressive models of the world, and structured experience arises from running such models. Pure awareness may correspond to experiences with minimal structure achieved through meditation, psychedelics, or other deconstructive practices, such as jhāna meditation. A key hypothesis is that the phenomenology of pure awareness arises from the agent's model of its own modeling process, and this recognition can occur alongside other phenomenal content, as in non-dual awareness. These ideas can be explored through whole-brain computational models based on predictive processing, grounded in meditation and psychedelic research.
Philosophy and the Mind Sciences
May 2, 2022
Chiara Caporuscio, Sascha Benjamin Fink
1 citation
A book symposium on Chris Letheby's Philosophy of Psychedelics (2021) examines the tension between psychedelic therapy and philosophical naturalism. The special issue opens with an introduction by Matthew Johnson, followed by Letheby's overview of his main arguments. Seven contributions either critique or expand on Letheby's proposed mechanism for psychedelic therapy or discuss its epistemic implications. The symposium concludes with Letheby's responses to the commentaries.
Philosophy and the Mind Sciences
July 6, 2026
Niccolò Negro
Analogical abduction combines analogical reasoning with inference to the best explanation to justify claims about consciousness in others. This paper applies that method to fetuses at the end of the second trimester, using a three-step recipe. Given the best minimal model of adult human consciousness and current evidence on fetal brain architecture, the argument supports the conclusion that these fetuses are probably not conscious. The work also shows both the strengths and limits of analogical abduction as a theory-light tool for detecting consciousness across different populations.
Philosophy and the Mind Sciences
July 6, 2026
Richard Brown
Higher-order theories of consciousness are empirical conjectures that can be tested and potentially falsified. The author examines what these theories imply about infant consciousness, focusing on Ned Block's argument that infants aged 6–11 months have conscious color experiences without possessing color concepts. The author contends that Block's argument does not disprove higher-order theories but instead raises empirical questions that could help distinguish between different versions of the theory or determine whether the approach is viable.
Philosophy and the Mind Sciences
July 6, 2026
Jacob Berger, Lori M. Curtindale
A method for determining whether nonverbal organisms like human infants are conscious, called the marker methodology, has gained attention but is fundamentally flawed. This approach uses markers thought to correlate with consciousness instead of relying on theories of consciousness. The authors argue that this method is unlike other scientific investigations because its markers are derived neither from theory nor from commonsense conceptions of the target phenomenon. They contend the marker method should be abandoned and propose using commonsense markers instead to explore infant and other forms of consciousness.
Philosophy and the Mind Sciences
June 25, 2026
Wim Pouw
Iconicity is the informative relation between an utterance's form and its meaning, but defining it formally is difficult. Researchers often base iconicity on resemblances, yet philosophical critiques of depiction raise fundamental issues against resemblance-based accounts. Recent work argues that iconicity should abandon objective resemblances and instead be understood as in the eye of the beholder, reflecting a struggle between iconicity as a property of mind versus environment. This paper proposes an alternative relational ontology informed by 4E cognition approaches, which view iconicity as arising from a niche-constructed organism-environment system. The account offers a philosophical ontology and working definition that keeps iconicity verifiable and context-dependent without reducing it to either objective resemblances or subjective mental states.
Philosophy and the Mind Sciences
May 27, 2026
Vivian Mizrahi
Smell and taste, unlike vision, touch, and hearing, are directly oriented toward stuffs rather than individual objects. Stuff constitutes an irreducible ontological category distinct from both individuals and universals. Chemistry itself is best understood as a science of stuffs rather than of atoms or molecules. The distinctive phenomenology of smell and taste—including mixture, concentration, and the sense of presence—is best explained by a stuff theory of their proper objects. This view has implications for how to individuate the senses of smell and taste.
Philosophy and the Mind Sciences
February 11, 2026
Jeffrey Yoshimi, Jason Ford
The authors propose a structuralist account of conscious experience by examining the parts that compose the minimal sense of self. Using a variational method, they argue that the feeling of agency, the feeling of privacy, and the feeling of “me-ness” are separable components that can be dissociated in various combinations, as supported by empirical and clinical cases. Removing or altering any of these components changes the whole experience in a holistic but determinate way, much like altering an instrument in a symphony alters the overall sound.
Philosophy and the Mind Sciences
February 9, 2026
Sascha Benjamin Fink, Andrew Y. Lee
Conscious experiences have many structural features, such as color experiences varying in hue, saturation, and brightness, decreasing visual acuity from the center to the periphery of the visual field, pain experiences in different magnitudes, and temporal experience flowing as a continuous stream. Structuralism, broadly defined, is an approach to consciousness research focused on investigating these structures. Varieties include methodological structuralism, which holds that scientific methods yield knowledge only of structural features, and ontic structuralism, which claims consciousness is nothing but structure. This special volume collects articles on the structures of conscious experiences and their role in research, aiming to establish a foundation and agenda for a structuralist research program in the science of consciousness.