Predictive processing (PP) accounts of perception are unique not merely in that they postulate a unity between perception and imagination. Rather, they are unique in claiming that perception should be conceptualised in terms of imagination and that the two involve an identity of neural implementation. This paper argues against this postulated unity, on both conceptual and empirical grounds. Conceptually, the manner in which PP theorists link perception and imagination belies an impoverished account of imagery as cloistered from the external world (...) in its intentionality, akin to a virtual reality, as well as endogenously generated. Yet this ignores a whole class of imagery whose intentionality is directed on the actual environment—projected mental imagery—and also ignores the fact that imagery may be triggered crossmodally in a bottom-up, stimulus-driven way. Empirically, claiming that imagery and perception share neural circuitry ignores relevant clinical results in this area. These evidence substantial perception/imagery neural dissociations, most notably in the case of aphantasia. Taken together, the arguments here suggest that PP theorists should substantially temper, if not outright abandon, their claim to a perception/imagination unity. (shrink)

What is the relationship between perception and mental imagery? I aim to eliminate an answer that I call perceptualism about mental imagery. Strong perceptualism, defended by Bence Nanay, predictive processing theorists, and several others, claims that imagery is a kind of perceptual state. Weak perceptualism, defended by M. G. F. Martin and Matthew Soteriou, claims that mental imagery is a representation of a perceptual state, a view sometimes called The Dependency Thesis. Strong perceptualism is to be rejected since it misclassifies (...) imagery disorders and abnormalities as perceptual disorders and abnormalities. Weak Perceptualism is to be rejected since it gets wrong the aim and accuracy conditions of a whole class of mental imagery–projected mental imagery–and relies on an impoverished concept of perceptual states, ignoring certain of their structural features. Whatever the relationship between perception and imagery, the perceptualist has it wrong. (shrink)

Imagination is widely thought to come in two varieties: perception-like and belief-like imagination. What precisely sets them apart, however, is not settled. More needs to be said about the features that make one variety perception-like and the other belief-like. One common, although typically implicit, view is that they mimic their counterparts along the conceptuality dimension: while the content of belief-like imagination is fully conceptual, the content of perception-like imagination is fully non-conceptual. Such a view, however, is not sufficiently motivated in (...) the literature. I will show that there are good reasons to reject it and I will argue that both varieties of imagination involve fully conceptual contents. I will suggest an alternative way to draw the distinction between perception-like and belief-like imagination along the conceptuality dimension, according to which only perception-like imagination requires observational concepts. (shrink)

Though researchers working on congenital aphantasia (henceforth “aphantasia”) agree that this condition involves an impairment in the ability to voluntarily generate visual imagery, disagreement looms large as to which other impairments are exhibited by aphantasic subjects. This article offers the first extensive review of studies on aphantasia, and proposes that aphantasic subjects exhibit a cluster of impairments. It puts forward a novel cognitive theory of aphantasia, building on the constructive episodic simulation hypothesis of memory and imagination. It argues that aphantasia (...) is best explained as a malfunction of processes in the episodic system, and is therefore an episodic system condition. (shrink)