In Thomistic epistemology having phantasms in the mind is central, out of which the mind extracts a universal, the activity of the active intellect characteristics of rational beings (like us). But people who has been diagnosed with aphantasia can still do this very fundamental mind activity (such as recognizing the dogness out of instances of dogs that one sees).

On the surface it looks like a counter-example to Thomistic epistemology. How do modern Thomists tackle the medical condition of aphantasia to preserve the central place of phantasm in human cognition? It would be great if in addition, the answer can elaborate whether the issue was anticipated by pre-modern Thomists.

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    The question can be posed to all Aristotelians, not just Thomists, the idea comes from Aristotle himself:"The soul never thinks without a mental image [phantasma]" (De Anima). SEP points out a similar problem:"His suggestions in this direction may seem unfortunate, since for a broad range of thoughts, images, construed naturally and narrowly as pictorial representations, seem unnecessary or even plainly irrelevant". They suggest that his equating of thinking with imagining should be "tempered" and not apply universally.
    – Conifold
    Commented May 30 at 5:45
  • @Conifold Thanks. Can I then expect modern Thomists and modern Aristotelians solve the problem similarly, or is there specific element of Thomist epistemology (which probably borrows from Augustine / Neoplatonism or even from Christian theology) influencing Thomistic solution that modern / purist Aristotelians would loath to take? Commented May 31 at 13:47

1 Answer 1


Not an example of an approach to the problem, by Thomists, per se, but at least by those who might advance the same local thesis as Thomists would: from the SEP article on mental imagery:

... not everyone conjures up vivid and distinct images when they have mental imagery (see Kind 2017 for a summary of the vividness of imagery). There are people who, when they close their eyes and visualize an apple see no ‘images’ in their mind’s eye. They are referred to as aphantasics, a label that just means that they report no conscious mental imagery (Zeman et al. 2010). Aphantasia can have many causes, some having to do with voluntary control, some with the phenomenology of early cortical representations. But at least some aphantasics seem to have mental imagery that they are not aware of: they have unconscious mental imagery (Koenig-Robert and Pearson 2021, Nanay 2021c, see also Phillips 2014, Church 2008, Emmanouil and Ro 2014, Brogaard and Gatzia 2017 on unconscious mental imagery).

The very idea of unconscious mental imagery may raise some philosophical eyebrows and some philosophers indeed build consciousness into their definition of mental imagery (Richardson 1969, pp. 2–3, Kung 2010, p. 622). But if mental imagery is perceptual representation that is not directly triggered, then the bar for unconscious mental imagery should not be higher than the bar for perception per se, that is, for perceptual representation that is directly triggered. And we have plenty of evidence that perception is often unconscious: subjects with blindsight are not conscious of what they are staring at, but what they see systematically influences their behavior. And the same goes for healthy subjects when they look at very briefly presented or masked stimuli (see, e.g., Kentridge et al. 1999, Kouider & Dehaene 2007 as two representative examples of the vast literature on unconscious perception). If perception can be unconscious, then so can mental imagery.

Aphantasia comes on a spectrum. Researchers put together the so-called ‘vividness of visual imagery questionnaire’, which indicates how vivid one’s (visual) mental imagery is. Aphantasics score very low on this scale. People with very vivid mental imagery (often referred to as hyperphantasics) score very high. But most people are somewhere in between. These interpersonal variability in the vividness of mental imagery should make us even more wary of using introspective criteria for characterizing mental imagery as this would give different results in different people on different parts of the aphantasia-hyperphantasia spectrum.

Arguably, "unconscious mental imagery" is incompatible with the role meant to be played by the agent intellect, here; so perhaps it's not enough to claim that there is such a thing in order for the Thomistic thesis to be able to go through. Or, since not even the word "conscious" is altogether clear and simple, perhaps we might think that being conscious of the activity of the agent intellect, in operating upon phantasms, can amount to being unconscious (or at least subconscious) in some other sense even so.

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    Thanks for the answer; will read the SEP article before providing more feedback. Another avenue to research is whether "unconscious mental imagery" is fine with Thomistic active intellect; it probably IS but then would probably need to worry whether the underlying brain condition prohibits phantasms to form, which will throw a wrench in the machinery (since modern Thomism seems to be very "physicalist"); i.e. this being red-flag for the existence of "unconscious" mental imagery. On the other hand, they can argue that the unconscious is primary but it doesn't seem to be Aristotelian enough. Commented May 29 at 16:21

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