What is Synesthetic Color? John Roman McMaster University 

What is Synesthetic Color? • What would the main views in color ontology say about synesthetic color? – Would they call synesthetic colors real? – If real, how would they ascribe synesthetic color properties? – How would they distinguish synesthetic colors from normal colors? 

Preview [1] Affirm the reality of synesthetic color [2] Distinguish synesthetic color from normal color [3] Avoid the ontological excess of ascribing synesthetic colors to external objects Realism: [2] and ([1] or [3]) Anti-Realism: [3] Adverbialism: [1], [2], [3] 

1. What is Synesthesia? • …a neurological condition in which the stimulation of one sensory modality or cognitive pathway leads involuntarily to experiences in a second modality or cognitive pathway. – Inducer: the original stimulus – Concurrent: the experience in the secondary modality or cognitive pathway • Color synesthesia: cases of synesthesia in which the concurrent is color – E.g., Sound-color (inducer: sound of a church organ; concurrent: experience of greenness) – Variation in inducer-type and inducer-concurrent associations • Associative vs. Projective – Projective: colors experienced as in the visual field – Associative: colors experienced as “in the mind’s eye or head” (MacPherson 2007) • Involuntary, vivid, reliably associated 

1. What is Synesthesia? • The problem of synesthetic colors – Unlike hallucinatory color, they involve an interaction with external stimuli – Unlike normal color, they do not involve the stimuli that the visual system typically exploits – Unlike illusory color, they do not inhibit or obscure our interactions with the external world • A tension between abnormality and usefulness 

1. What is Synesthesia? • Synesthetic colors are illusory if synesthetic colors are… (a) maladaptive: they interfere with a perceiver’s environmental interactions; OR (b) essentially non-veridical: only normal colors can represent external stimuli • No strong evidence for (a) – See Baron-Cohen 1996; Ramachandran & Hubbard 2001; Cytowic 2002; Blake et al. 2005 • Main motivation for (b) seems to be prior commitment to externalist representationalism – Unnecessarily restricts the relationship between representational content and phenomenal character 

2. Locating Synesthetic Color The location problem: “[C]olours must, if they are instantiated anywhere, be findable somehow” (Jackson 1998, 87). If colors are properties of objects, then colors are real… • Realism*: Colors are properties of objects. Therefore, colors are real. • Anti-Realism: Colors are not properties of objects. Therefore, colors are not real. 

2. Locating Synesthetic Color • If synesthetic color is real… – Realism: ontological excess – Anti-Realism: N/A • If synesthetic color is not real… – Realism: affirm normal, deny synesthetic – Anti-Realism: indistinguishable 

3. Color Adverbialism (Chirimuuta) • Colors are properties of perceptual interactions between perceivers and stimuli. – Avoids the location approach: “there is no color-in- the-object, on the one hand, and color-in-the-mind, on the other; there is just one color—the property of a perceptual process” (Chirimuuta 2015, 154). – Perceptual process: a perceiving event – Property: an adverb 

3. Color Adverbialism (Chirimuuta) • Perceptual pragmatism – “What does it take for a perceptual state to be right?” • Pragmatism: “it must work—it must be a useful guide to the surrounding environment” (109) • Correspondence: the external world must correspond to what the perceptual state represents – “What are perceptual states for?” • Pragmatism: “to help you to live by guiding your activity in the world” (110) • Correspondence: to detect what is in the external world 

3. Color Adverbialism (Chirimuuta) • “Colors are properties of perceptual interactions involving a perceiver (P) endowed with a spectrally discriminating visual system (V) and a stimulus (S) with spectral contrast of the sort that can be exploited by V” (Chirimuuta 2015, 140) • P = “any sighted animal with the right kind of visual system” • V = “the visual machinery of all creatures conventionally classified as having color vision proper” • S = any excitation which “bear[s] spectral contrast,” i.e., “reflect[s] or generate[s] patterns of light with wavelengths in the discriminable range of at least one kind of visual system” 

3. Color Adverbialism, Revisited • Normal colors are properties of perceptual interactions involving a perceiver (P) endowed with a spectrally discriminating visual system (VNORM ) and a stimulus (SNORM ) with spectral contrast of the sort that can be exploited by VNORM . • Synesthetic colors are properties of perceptual interactions involving a perceiver (P) endowed with a synesthetic sensory system (VSYN ) and a stimulus (SSYN ) that does not involve spectral contrast but that VSYN can exploit to produce experience that is qualitatively similar to normal color. • Colors are properties of perceptual interactions involving a perceiver (P) endowed with a color-perceiving sensory system (V) and a stimulus (S) that induces color experience. 

Review [1] Affirm the reality of synesthetic color [2] Distinguish synesthetic color from normal color [3] Avoid the ontological excess of ascribing synesthetic colors to external objects Realism: [2] and ([1] or [3]) Anti-Realism: [3] Adverbialism: [1], [2], [3] 

4. Problems for Color Adverbialism 4.1. Perceiver-dependence – Since colors are properties of interactions, their existence depends on perceivers and stimuli – Cohen: it seems “counterintuitive” and “idealistic” to suppose that “colors go in and out of existence with these events—say, when perceivers die, close their eyes, or shift their attention” – Response: adverbialism doesn’t deny the existence of the components of these interactions—rather, it denies that there is color without their interaction 

4. Problems for Color Adverbialism 4.1. Perceiver-dependence – Response (cont’d): Perceiver-dependence is an essential aspect of synesthetic color • Synesthetic colors do “go in and out of existence with [their] events” and when perceivers “shift their attention” 

4. Problems for Color Adverbialism 4.2. Predication – Adverbialism claims colors qualify events rather than individuals – Cohen: this view conflicts with the grammatical structure of color predication in natural language – Response: individual-predication is sometimes inadequate for describing normal color experience, but especially inadequate for synesthetic color experience 

4. Problems for Color Adverbialism 4.3. Phenomenology – Cohen: colors look like properties of individuals, not properties of events – Response: some color phenomena look like properties of events, not individuals (e.g., Benham disk) – It seems at least possible, though perhaps implausible, to see surface color in the same way (Pasnau 2009) – Many forms of synesthetic color experience involve motion and dynamic form, two things that the individual-view has difficulty capturing (Cytowic 2002) 

Conclusion • If synesthetic colors are no less real than normal colors, adverbialism seems best equipped to deal with them – (if they are real…) • Two paths forward: (i) Offer more compelling arguments for why synesthetic colors are illusory (ii) Revise our theories to accommodate them