The kinematic consequences of special relativity can be expressed in three-dimensional language. Remarkably, this does not mean that, for making special relativity operational, positing a three-dimensional ontology is as good as positing the four-dimensional ontology. This is a singular limitation, whose nature is worth close inspection. In exploring it not just within a traditional, kinematic or geometric perspective but in its modern scientific context – i.e. as regards (1) causation, (2) localized observers that physics finds in nature and are not (...) mere short forms for reference frames, and (3) the semiosis they develop and use to make reference to distant present objects – this essay pursues two aims. First, to put on view that the block universe outlook, regarding the macroscopic-scale universe as a timelessly existing four-dimensional world each of whose diverse items is composed of temporal parts, despite its being ontologically incorrect is indeed the only one that is consistent with special relativity, whose calculations are correct. This is tantamount to point out that the special relativity's descriptions of the macrouniverse necessitate to portray time as a dimension, and moreover as an uncollapsed one; i.e., as a compass wherein mobility, in the vein of the translocative motion that may occur on every spatial dimension, ought to be at least conceivable. Second, to probe arguments defending that special relativity alone can resolve the debate on whether the extramental macroworld is three-dimensional or four-dimensional. In particular, since relativity's condition of possibility, namely the imposition on relativistic observers of describing at once past, present, and future states along the length of the observed moving entities, has been considered a proof that past and future components of real entities enjoy an unremitting mode of existence, the main argument probed in this paper is the one claiming that "if the world were three-dimensional, the kinematic consequences of special relativity and more importantly the experiments confirming them would be impossible." This is acknowledged as exact but it is remarked that, such imposition being a Kantian condition of possibility, it cannot reveal anything about what Kant called noumenon, i.e. extramentality. (shrink)