Terence Edward "Terry" Horgan (born October 13, 1948) is an American philosopher and a professor at the University of Arizona in Tucson. His areas of expertise include philosophy of mind and metaethics.

Horgan obtained his bachelor's degree in philosophy in 1970 from Stanford University. In 1974, he completed his Ph.D. at the University of Michigan under the supervision of Jaegwon Kim, with his dissertation titled "Microreduction and the Mind-Body Problem." After holding professorships in Illinois, Michigan, and Memphis, Horgan has been a professor in Tucson, Arizona since 2002.

Phenomenal intentionality Horgan has written many works on phenomenal intentionality, which is the idea of "an internal, narrow type of intentionality that is not only determined by phenomenology but is constituted by it". Horgan and his co-authors have been credited with inaugurating the "Phenomenal Intentionality Research Program".

Phenomenal intentionality theory (PIT)

Horgan is a leading proponent of the view that intentionality is grounded in phenomenal consciousness, often called the phenomenal intentionality theory (PIT). With John L. Tienson he argued that there exists "a kind of intentionality, pervasive in human mental life, that is constitutively determined by phenomenology alone," articulating the paired theses of the intentionality of phenomenology and the phenomenology of intentionality, and developing a "phenomenal duplicates" argument for the prevalence of phenomenal intentionality.Horgan, Terence E.; Tienson, John L. (2002), "The intentionality of phenomenology and the phenomenology of intentionality," in D. J. Chalmers (ed.), pp. 520–533. In the same context Horgan and Tienson also contrasted PIT with what they dubbed "separatism," on which consciousness and intentionality are metaphysically independent.Horgan, Terence E.; Tienson, John L. (2002), "The intentionality of phenomenology and the phenomenology of intentionality," in D. J. Chalmers (ed.), pp. 520–533.

Together with George Graham and Tienson, Horgan developed PIT in a moderate, derivativist direction: many non-phenomenal intentional states (for example, standing beliefs) have their content in virtue of suitable functional or other systematic relations to phenomenal intentional states, rather than being phenomenal themselves.Graham, George; Horgan, Terence E.; Tienson, John L. (2007), "Consciousness and intentionality," in M. Velmans & S. Schneider (eds.), pp. 468–484. They further defended internalism and a corresponding account of narrow content via "brain-in-a-vat" scenarios, arguing that phenomenal consciousness provides the best basis for narrow intentional content even if reference and truth-conditions involve external relations.Horgan, Terence E.; Tienson, John L.; Graham, George (2004), "Phenomenal intentionality and the brain in a vat," in R. Schantz (ed.), pp. 297–318.

Horgan has also linked PIT to issues of content determinacy, contending (with Graham) that purely physical, functional, or informational facts underdetermine the specific contents we represent (e.g., RABBIT vs. UNDETACHED-RABBIT-PARTS), and that appeal to phenomenal character helps explain how content is fixed.Horgan, Terence; Graham, George (2012), "Phenomenal Intentionality and Content Determinacy," in R. Schantz (ed.), Prospects for Meaning, Berlin: De Gruyter, pp. 321–344. In parallel, he has been a prominent defender of cognitive phenomenology: he connects agentive phenomenology to thought phenomenology,Horgan, Terence (2011a), "From Agentive Phenomenology to Cognitive Phenomenology: A Guide for the Perplexed," in T. Bayne & M. Montague (eds.), pp. 57–78. doi:10.1093/acprof:oso/9780199579938.003.0003. argues for the evidential role of perceptual experience,Horgan, Terence (2011b), "Phenomenal intentionality and the evidential role of perceptual experience: comments on Jack Lyons, Perception and Basic Beliefs," Philosophical Studies 153(3): 447–455. and maintains that original (non-derived) intentionality is phenomenal intentionality.Horgan, Terence (2013), "Original Intentionality is Phenomenal Intentionality," The Monist 96(2): 232–251.

Across these contributions, Horgan (often with Tienson and Graham) has used a range of phenomenological devices—contrast cases, spontaneous-thought examples, and agency-involving experiences—to argue that much of a thinker's web of belief and desire is structured by, or derives from, phenomenal character.Horgan, Terence E.; Tienson, John L. (2002), "The intentionality of phenomenology and the phenomenology of intentionality," in D. J. Chalmers (ed.), pp. 520–533.Graham, George; Horgan, Terence E.; Tienson, John L. (2007), "Consciousness and intentionality," in M. Velmans & S. Schneider (eds.), pp. 468–484.

Moral phenomenology Horgan has applied his phenomenological theories in investigating moral issues (moral phenomenology), such as formulating a theory of the supererogatory.

Narrow mental content

Horgan has been a central proponent of linking phenomenal intentionality to narrow mental content. With John Tienson (and later with George Graham), he argues that there is a pervasive kind of intentionality that is constitutively fixed by phenomenology alone, and that phenomenology itself depends only on an individual's intrinsic (narrow) properties. Taken together, these claims support the existence of widespread narrow content: if phenomenal character is narrow and phenomenal character determines intentional content, then much intentional content is narrow as well.Horgan, Terence; Tienson, John (2002). "The Intentionality of Phenomenology and the Phenomenology of Intentionality". In D. Chalmers (ed.), Philosophy of Mind: Classical and Contemporary Readings. Oxford University Press.Horgan, Terence; Tienson, John; Graham, George (2004). "Phenomenal Intentionality and the Brain in a Vat". In R. Schantz (ed.), The Externalist Challenge. Berlin: Walter de Gruyter.

To motivate both premises, Horgan, Tienson, and Graham adapt brain-in-a-vat scenarios: a physical duplicate of a subject's brain, sustained and stimulated so as to match the subject's internal states, would (they contend) share the subject's phenomenology; because phenomenal character fixes phenomenal intentional content, many of the duplicate's intentional contents would match the original's too. This is intended to show both the narrowness of phenomenology and the reality of phenomenally determined (hence narrow) content.

Although perceptual experience is the most immediate case, Horgan and collaborators extend the program beyond perception, arguing for distinctive phenomenologies of agency and of propositional attitudes (belief, desire), and for the thesis that all intentionality is either identical with, or derived from, phenomenal intentionality—thereby grounding a broad class of narrow contents for thought as well.

On the theoretical side, Horgan and Tienson suggest affinities between their approach and two-dimensional modal semantics for characterizing content, while related work with Uriah Kriegel emphasizes a broadly descriptive connection between phenomenal intentionality and reference.Kriegel, Uriah; Horgan, Terry (forthcoming). "The Phenomenal Intentionality Research Program". In T. Horgan; U. Kriegel (eds.), Phenomenal Intentionality: New Essays. Oxford University Press.

General ontology

In metaphysics, Horgan defends austere realism, an ontological position developed with Matjaž Potrč. Austere realism combines a minimalist ontology with a contextual theory of truth. The ontology is "austere," excluding most common-sense objects, yet ordinary statements about such entities can still be true via semantic correctness under contextual standards.

In Austere Realism: Contextual Semantics Meets Minimal Ontology (2008), Horgan and Potrč defended a version called blobjectivism: the view that only one concrete particular exists—the entire cosmos ("the blobject"). Thus, Horgan and Potrč's view is a form of "Existence Monism". This entity has enormous spatiotemporal variability but no proper parts. Truth, on their account, is a matter of indirect correspondence rather than mirroring discrete objects. This view has been discussed in metametaphysical debates.

Philosophy of mind In the philosophy of mind, Horgan has investigated the possibility of a physicalist interpretation of consciousness.

Views on the knowledge argument about qualia

In a 1984 paper, Horgan criticized Frank Cameron Jackson's dualistic thought experiment known as "Mary's Room" as merely exploiting an ambiguity in the notion of physical information, rendering it inconclusive since "physical information" carries different meanings in various premises. Since 2002, Horgan has begun arguing against it using conceivability arguments in the tradition of Saul Kripke and David Chalmers.

Views on reductionism and multiple realizability In a 1993 paper, Horgan raised methodological caveats about reductionism regarding mind, resting ultimately on multiple realizability. He wrote:Multiple realizability might well begin at home. For all we now know (and I emphasize that we really do not now know), the intentional mental states we attribute to one another might turn out to be radically multiply realizable at the neurobiological level of description, even in humans; indeed, even in individual humans; indeed, even in an individual human given the structure of his central nervous system at a single moment of his life. (p. 308; author's emphases)

Views on supervenience Regarding the supervenience of the mental on the physical, Horgan has promoted the notion of "superdupervenience" (a term coined by William Lycan) as well as his own formulations of what he called "regional supervenience".

In an essay from 2002, Horgan describes his ambivalent stance towards physicalism as follows: "I remain deeply attracted to materialism in philosophy of mind; I would like to believe that the mental is superdupervenient on the physical. But the whole hard problem looks very hard indeed, and I see no prospects currently in sight for dealing with it satisfactorily. […] Much as I would like to be a materialist, at present I do not know what an adequate materialist theory of mind would look like."

Metaethics and moral philosophy

Horgan, with Mark Timmons, developed the Moral Twin Earth argument. In New Wave Moral Realism Meets Moral Twin Earth (1991), they adapted Putnam's Twin Earth thought experiment to moral terms. They showed that if moral terms could pick out different properties on a twin Earth, then synthetic moral naturalism faces serious problems. This thought experiment has been called the "central difficulty" against an objection against Moore's "open question argument" against moral naturalism.

Horgan's approach to supervenience of moral truths on natural truths, relying on "superdupervenience", has been influential.

In subsequent work, Horgan and Timmons defended cognitivist expressivism (also called nondescriptivist cognitivism). This hybrid theory holds that moral judgments are cognitive states (beliefs) but not descriptive representations of stance-independent facts. Rather, they express evaluative attitudes while still being truth-apt under minimalist semantics. This approach explains the objectivity-like feel of moral discourse without positing robust moral facts.

Decision theory

Regarding Newcomb's problem, Horgan supports one-boxing, but believes that this cannot be demonstrated to be the only rational solution to the problem, because it is a "deep antinomy of practical reason" where both solutions are supported by principles that are constitutive of practical rationality.

Epistemology