Situated at the junction of Cognitive Semantics and Experimental Phenomenology, this study investigates how participants perceive the structure of 18 perceptual dimensions of opposites across the visual, auditory, tactile, gustatory and olfactory sensory modalities. The structures include three components: two poles (high; low) and an intermediate (neither high nor low). Participants were asked to provide examples of contexts for each dimension for which they could experience the five sensory modalities and then describe their experiences of the structures with respect to whether the poles were experienced as a single property (Point), or a range of properties with or without a precise limit (Bounded Range or Unbounded Range respectively). For the intermediate region, they described if they experienced a single property (Point) or many (Range) or none (No Intermediates). The study centres on two main questions. Is the perceptual structure invariant across the sensory modalities? If not, how do the structures differ? The study shows that the overall structure of all dimensions was stable in at least two of the modalities, and many structures were stable across more than two modalities. Stability was particularly pertinent across the visual and tactile modalities, and the gustatory and olfactory modalities.