Summary: Researchers argue that aphantasia—the complete inability to form voluntary mental images—poses a serious challenge to David Hume’s imagistic account of thought and to contemporary image‑based models of cognition. People with severe aphantasia report a total blank when asked to visualize a rainbow, a loved one’s face, or their childhood bedroom; they describe absolute darkness. Yet they reason about geometry, recognize acquaintances, and engage with abstract moral and mathematical ideas with the same fluency as anyone else.
Key Facts
- The Humean bottleneck questioned: Uku Tooming and Roomet Jakapi argue that if abstract thought required vivid mental imagery in the way Hume proposed, people with aphantasia should have profound trouble with abstract domains such as geometry, ethics, and mathematics. Empirical evidence shows they do not, implying that abstract reasoning can proceed without sensory images.
- Not explained by other senses: A common counterargument is that aphantasics replace visual images with auditory, tactile, or other sensory imagery. The researchers point out that many aphantasics lack imagery across modalities (sight, sound, touch, taste), yet still perform normally on abstract tasks.
- Unconscious imagery is insufficient: Another defense suggests that imagery may be generated unconsciously, even if unavailable to awareness. The paper reviews recent neuropsychological work indicating a lack of both conscious and unconscious imagery in severe cases, undermining that claim.
- Spatial schemata lack sensory richness: Some aphantasics use schematic spatial knowledge—an awareness of layout or relations without pictorial detail. But Hume’s account treats sensory richness as essential for abstraction; purely schematic spatial representations lack the vividness Hume deemed necessary.
- Words without images: The idea that aphantasics think only in words (e.g., using the word “triangle” as a stand‑in for an image) fails under a strict Humean reading, since Hume assumed words gain meaning through association with sensory ideas.
- Not merely an odd exception: Treating aphantasia as an isolated exception would imply an implausible psychological split between aphantasics and the rest of humanity. Instead, the findings suggest human thought is more flexible than 18th‑century imagistic theories allow.
Source: Estonian Research Council
Most people, when asked to think about triangles, dogs, or justice, spontaneously summon some mental picture: a triangle on a blackboard, a scruffy terrier, a courtroom scene.
David Hume, the 18th‑century Scottish philosopher, took this phenomenon to indicate a general structure of human thought. He proposed that abstract concepts are constructed from imaginative operations on sensory ideas: to think about the general notion of a triangle, the mind first conjures a particular triangle and manipulates it mentally. In Hume’s view, words and abstract rules rest on a foundation of sensory images.
People with severe aphantasia challenge that picture. They report a complete absence of mental imagery: nothing appears in the “mind’s eye.” Still, they recognize faces, reason about shapes, solve mathematical problems, and deliberate about moral dilemmas. If Hume’s account were universally true, this cognitive competence should be impossible without imagery.
In a paper published in Neuropsychologia, University of Tartu Associate Professor of Theoretical Philosophy Uku Tooming and Associate Professor of History of Philosophy Roomet Jakapi present a systematic critique of Hume’s imagistic theory using empirical and conceptual evidence from studies of aphantasia. As Tooming summarizes: “If abstract thought genuinely required mental imagery, people with aphantasia should struggle to think abstractly. They do not.”
How can abstract thought work without images?
The authors evaluate several responses that aim to reconcile aphantasia with Humean abstraction and find them wanting. One response is that aphantasics simply rely on non‑visual sensory imagery. Evidence from multimodal aphantasia—where imagery is absent across senses—undercuts this move.
Another proposal is that imagery may be involuntary or unconscious, supplying the mental content Hume requires even when people report no conscious images. The paper reviews neuropsychological studies and argues that severe aphantasia shows an absence of imagery at both conscious and measured unconscious levels, making this defense unpersuasive for the most affected cases.
A different avenue appeals to schematic spatial representations: knowing relational layouts or geometric relations without pictorial detail. While such spatial knowledge supports practical reasoning, it lacks the sensory vividness central to Hume’s account and therefore does not restore the imagistic foundation he envisioned.
Finally, the idea that language alone provides conceptual content (thinking in words rather than images) fails to meet the Humean requirement that words derive meaning from underlying sensory ideas. Thus, none of these replies fully rescues Hume’s model.
More than a philosophical exception
The authors also reject the claim that aphantasia is a harmless outlier to be ignored by theory. If people with aphantasia can perform complex abstract reasoning without images, then image‑based theories of cognition cannot claim to capture the essential architecture of thought. This has consequences for cognitive science and philosophy of mind, where imagistic models remain influential. The evidence suggests that mental representation can be accomplished by non‑imagistic, more abstract formats—linguistic, structural, or computational—calling for a reappraisal of theories that treat imagery as foundational.
A: Hume characterized the mind as operating like an internal sensory theater. He argued that to grasp a general idea (for example, “triangles”) the mind first summons a particular sensory representation of a triangle and then performs imaginative operations on that representation. For Hume, abstract ideas are built from these sensory-derived mental images.
A: Aphantasics appear to think conceptually and relationally rather than pictorially. They rely on definitions, rule‑like structures, linguistic descriptions, and relational knowledge to represent categories and reason about them. For example, understanding a triangle can come from grasping rules about points and lines rather than from visualizing a drawing.
A: The study pushes cognitive science to move beyond visual‑centric assumptions. If people can think abstractly without imagery, dominant imagistic models must be revised to accommodate non‑pictorial formats of representation. This invites new research into how information is encoded and processed in the brain when sensory imagery is absent.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by staff.
About this aphantasia research news
Author: Mikk Viilukas
Source: Estonian Research Council
Contact: Mikk Viilukas – Estonian Research Council
Image: The image is credited to Neuroscience News
Original Research: Open access. “Aphantasia as a challenge for Humean abstraction” by Uku Tooming and Roomet Jakapi. Neuropsychologia. DOI: 10.1016/j.neuropsychologia.2026.109465
Abstract
Aphantasia as a challenge for Humean abstraction
This paper reassesses David Hume’s imagistic theory of thought in light of empirical and philosophical evidence about aphantasia. Hume’s account holds that abstraction depends on imaginative operations on individual ideas that originate as sensory impressions. The authors argue that if individual ideas are equated with mental imagery, then people with severe aphantasia—who lack the capacity to form such imagery—should be unable to perform abstract thought. Empirical findings show they can. From this premise the paper concludes that abstraction does not require the imaginative manipulation of sensory images, revealing a substantive limitation in Hume’s view and in imagistic models of cognition more generally.