[1]
This is a widespread claim that dates back to Plato and Aristotle and pervades the history of philosophy. See White (1990) for a good survey and a critical view of the standard picture (suggested by etymology) according to which imagination is akin to perception only. Among contemporary philosophers see also, for instance, Wollheim (1984), Williams (1976), Casey (1976), O’Shaughnessy (1980), Vendler (1984), Peacocke (1985), Walton (1990), Mulligan (1999), Kind (2001), Currie & Ravenscroft (2002), Martin (2002), Noordhof (2002), Chalmers (2002), Carruthers (2002), McGinn (2004), Goldman (2006), Byrne (2010).
[2]
Throughout the paper, we assume that experiences are conscious mental states.
[3]
Goldman himself acknowledges that these two treatments of imagination are similar (Goldman 2006, p. 52, fn. 21).
[4]
What is the relationship between sensory imagination and mental imagery? The latter phenomenon is at the heart of the well-known debate about the format of representations involved in cognitive tasks such as mental rotation (see Kosslyn 1980, 1994; Tye 1991; Pylyshyn 2002; Kosslyn et al. 2006). This debate concerns the kind of content of the relevant representations, and one of the issues is whether such content is propositional or iconic. In contrast, the notion of sensory imagination is defined here by reference to the psychological mode of the re-created mental state, namely a conscious perceptual experience. For our purposes we can leave open the nature of the contents of sensory imaginings.
[5]
At this point we can count at least the five senses (vision, audition, touch, taste, and olfaction) as sensory modalities. Later on, we shall suggest that a sensory modality involves an external perceptual perspective on the world. This excludes proprioception and the sense of agency as sensory modalities, insofar as they involve internal perspectives on oneself.
[6]
See section 7.2. As Thomas Metzinger reminded us, the existence of motor imagery has been acknowledged by twentieth century phenomenology. For instance, Karl Jaspers has coined the German term “Vollzugsbewusstsein”, which can be translated as “executive consciousness”.
[7]
Deafferented patients have lost the sense of proprioception; see e.g., Cole (1995) and Gallagher (2005).
[8]
Even if it turns out that motor imagery is constitutively dependent on sensory imagination, it is clearly not fully sensory, as we will shortly show. Note also that if motor imagery can be conceived as the re-creation of an essentially active phenomenon, namely the sense of agency or control, it need not be itself active. Although we cannot dwell on this issue here, imaginings can be either active, when we deliberately imagine something, or passive, as for instance when we are lost in an episode of mind wandering (see footnote 22).
[9]
If proprioception is a case of perception, there must be proprioceptive experiences. This has been contested, especially by Anscombe (1957). However, in our view, Anscombe conflates two different claims. The first claim, which we accept, is that there are no proprioceptive sensations. Proprioception is not a case of sensory perception. The second claim, which we reject, is that proprioception does not involve any conscious experience. Even if there are no proprioceptive sensations, we are consciously aware of the positions and movements of our body.
[10]
The idea that there are “self-informative methods,” i.e., ways of finding out about oneself, is pervasive in John Perry’s theory of self-knowledge; for a recent statement, see Perry (2011). As Perry makes clear, these methods can be either metaphysically or merely architecturally guaranteed. François Recanati makes use of a similar idea in his account of perspectival thought (Recanati 2007) and mental files (Recanati 2012); for instance, he writes: “In virtue of being a certain individual, I am in a position to gain information concerning that individual in all sorts of ways in which I can gain information about no one else, e.g. through proprioception and kinaesthesis” (Recanati 2007, p. 262).
[11]
This is an oversimplification, since many ordinary experiences have presumably both internal and external aspects. On the one hand, vision might involve both exteroception and interoception (Gibson 1966). On the other hand, proprioception and other forms of bodily experience often rely on visual information (Botvinick & Cohen 1998; de Vignemont 2013). Still, the external aspect of many ordinary visual experiences is clearly dominant, while visually aided proprioception remains essentially a way of gaining information about oneself, and thus is an internal experience in our sense.
[12]
To make our terminology as clear as possible, the distinction between internal and external experiences concerns the realm of non-imaginative states, while the analogous distinction between subjective and objective imagination concerns the realm of imaginative states. The question of whether imaginings themselves can be said to be internal or external is not raised in this essay.
[13]
Note that our definition leaves open the possibility that a particular imagining is both objective and subjective, to the extent that the re-created experience has both external and internal aspects (see footnote 11).
[14]
One might object that both cases involve subjective imagination, since the visual perspective of the rider, even if she does not see her own body, is tied to her proprioceptive experience; see the caveat voiced in footnote 11 above. Again, it might be that the distinction between subjective and objective imagination has really to do with the distinction between re-creating predominantly internal and re-creating predominantly external experiences.
[15]
For relevant discussion, see e.g., Cassam (1999), Bermúdez et al. (1995), Bermúdez (1998), Metzinger (2003), and Peacocke (2014).
[16]
A similar point is made by Mike Martin when he draws a distinction between “cases in which there is just an itch in the left thigh” in imagination and cases “in which one imagines some person whose behaviour reveals that they have an itch” (Martin 2002, p. 406, fn. 35; see also Dorsch 2012). However, according to his terminology, only the former cases count as being “from the inside”. Very often in the literature, the phrase “imagining from the inside” is used in this narrow sense (to refer to subjective imagination in our terminology) more than the broad sense meant by Peacocke (which refers to experiential imagination as a whole).
[17]
In fact, Mulligan speaks of a judgement-like, rather than a belief-like, type of imagination, which he calls “supposition”. It is not entirely clear whether his notion of supposition can be equated with what we call “cognitive imagination.” Very often in the literature, supposition is taken to be belief-like and, as such, nothing but cognitive imagination (Nichols & Stich 2003; McGinn 2004; Goldman 2006). An alternative view is that supposition is a sui generis type of imagination akin to acceptance rather than belief (Arcangeli 2011b). However, for present purposes we will skip this issue and consider only belief-like imagination.
[18]
See Metzinger (2003), Tye (2009), and Carruthers & Veillet (2011). Note that the standard view can lead to different attitudes toward the notion of cognitive imagination. On one attitude, cognitive imagination exists but is non-experiential. On another attitude, cognitive imagination does not exist or wholly reduces to sensory imagination (if, for instance, it is construed as auditory verbal imagination).
[19]
Crane (2013) defends a closely related view, according to which episodes of thinking, although not beliefs themselves, are phenomenally conscious. CogH can easily be adapted to accommodate Crane’s view.
[20]
In conversation, Peacocke confirmed that he intends GH to cover at least some cases of belief-like imagination.
[21]
Moreover, the question of whether these varieties of imagination exhaust the field of experiential imagination remains open. In order to answer it we would have to inquire as to whether there are other types of imagination, such as desiderative or desire-like imagination (see Currie & Ravenscroft 2002 and Doggett & Egan 2007 for a positive view, and Weinberg & Meskin 2006a and Kind 2011 for a critical view), affective or emotion-like imagination (see Goldman 2006 for a positive view, and Currie & Ravenscroft 2002 for a critical view) and judgement-like or acceptance-like imagination (see footnote 17). For lack of space, we have to defer this inquiry to another occasion.
[22]
This is only a selection of issues where we think our phenomenological and conceptual distinctions are relevant. We wish we had space to discuss other topics of relevance to the theory of imagination, such as mental time travel (Schacter & Addis 2007), dreams (Windt 2014), and mind wandering (Metzinger 2013). For instance, there are interesting issues having to do with the apparent lack of reflexivity of mind wandering episodes, and the tendency for the mind wanderer to identify herself with imagined protagonists (Metzinger 2013). A speculative hypothesis is that the passivity of mind wandering episodes causes various metacognitive errors, such as the error of confusing a case of subjective imagination with a genuine case of internal experience, which leads the imaginer to self-identify with the subject of the imagined mental state. Again, we have to leave this fascinating issue to another occasion.
[23]
There is also the interesting case of observing one’s own action in a mirror. The question here is whether the observer is aware that she is observing her own action. If the answer is negative, then the re-creation of the relevant experience belongs to objective imagination. If the answer is positive, as for instances when one uses visual information to control one’s action (think of a man shaving in front of the mirror), then the re-creation of the relevant experience may also belong to subjective imagination (see footnote 11).
[24]
The notion of imaginative project comes from Williams (1976). Imaginings are particular mental states, whereas imaginative projects can bind several imaginings in a coherent endeavour of imaginative world-making. The distinction is relevant even when a single imagining is at stake. Typically, an imaginative project will impose constraints, e.g., of an intentional or stipulative sort, on what is the case in the imagined world in addition to what is explicitly represented in an imagining.