Panthéon (Paris) is a recurring example in Jean-Paul Sartre’s analysis of how imagination differs from perception. Rather than describing the building as a setting, the book uses the absent structure to show that a mental image can present an object without supplying independent knowledge of it: what appears in the image depends on what the imaginer already believes or assumes.

The absent building as an example

Jean-Paul Sartre asks whether forming a mental image of Panthéon (Paris) can reveal how many columns support its pediment. It cannot. The image will show the number the imaginer believes to be there, or it may leave the number indeterminate. Imagining the building is therefore not a way of inspecting it from afar; the image offers no new evidence about its architecture.

The example makes a precise contrast with perception. A perceived object can disclose features that the observer did not already know, while an imagined object is presented with only the properties attributed to it. Sartre’s discussion notes that an image may fail to show the eighteen columns supporting the pediment and still be an image of Panthéon (Paris). The gap between the object and what the image depicts does not, by itself, prevent recognition; it exposes the limits of what imagining can establish.

Belief and the limits of imagery

The case also sharpens the role of knowledge in imaginative experience. The account calls this component knowledge, but its commentary observes that belief or opinion is more apt: a person can imagine an object on the basis of a false belief. Thus an image’s apparent detail is not a guarantee of accuracy. Its content follows the imaginer’s assumptions, rather than independently correcting them.

Panthéon (Paris) consequently illustrates a broader point about the difference between imagining and learning. The image may make the building present to thought in a particular way, but it cannot settle a question about the building that the imaginer does not already know. The example turns a familiar architectural feature—the columns beneath the pediment—into a test of whether vividness should be mistaken for observation.

Recurrence in the book

The index records Panthéon (Paris) at several points, including pages 38, 86–88, 128, and 131. In the discussion of the term remplir, the building appears again in connection with imagining it while absent: the example concerns whether imaginative presentation fulfils an act of consciousness, not whether it fills in missing architectural information. Across these appearances, the same absent building helps distinguish an image’s mode of presentation from the knowledge that would require encountering or otherwise establishing facts about its object.