Crecimiento inicial de la cámara de vapor

world toward a world in which the transcendental, intelligible levels of re- ality are seen as immanent in what is directly visible in everyday life. The most important role in this change, particularly in the visual arts, was played by the notion of “common sense”: the unifying faculty of all senses, the lower unity of meaning, and place of “sensible” judgment. The unity of common sense corresponds to the unity of things sensed in terms of their essential characteristics—common sensibles.89 _{Typical common sensibles}

are movement, rest, shape, unity, number, and magnitude, which includes sizes and distances.90 _{The ability to see magnitudes, according to the art}

historian David Summers, means not that we “can apprehend the exact di- mensions or distances of things but that what we apprehend is measurable and corresponds to the measurable.” It is for this reason that the history of common sense is closely bound up with optics: “Optics in fact might be de- scribed as the science of the common sense par excellence, and provides a clear example of the relation between common sense and reason. We always perceive particular shapes and magnitudes under real circumstances and therefore in a certain sense perceive them ‘incorrectly’ and optics tells us what we ‘really’ see.”91

Because the judgment of sense and the geometry of vision become so closely related, it is possible to discern a new relationship between the principles of medieval optics and the practical achievements of workshop perspective as early as the end of the fourteenth century. A decisive contri- bution was made by new interpretations of and commentaries on medieval optics. The most interesting, for our purposes, are the commentaries of Biagio da Parma (known also as Pelacani), particularly his unpublished trea- tise Quaestiones perspectivae.92_{In his writings Biagio, who belongs to the}

late medieval tradition as well as indirectly to the epoch of Brunelleschi, dis- cussed perspective and the questions of vision in a language focused on the tangible visual qualities, on the primary role of common sensibles, and on common sense. In Quaestiones perspectivae,Biagio’s main concern is cor- rectness of sight (iudicium sensus).93_{Such a question can be discussed but}

cannot be fully answered by verbal argument. For Biagio, the power to de- cide (virtus distinctiva) resided not in the intellect or in words but in sight itself. It is there, in the domain of visual experience, that the question will be addressed by the next generation.

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THE TRANSFORMATION OF THE VISIBLE WORLD

The new relationship between the world articulated by optics and the con- structions of linear perspective illustrates the transformation taking place in Florence in the first decade of the fifteenth century. Owing to a unique combination of historical circumstances, it was there that demonstrating the continuity between the optical interpretation of the medieval world (mainly cosmology and the problem of creation) and the perspectival repre- sentation of the visible world first became possible. This continuity was largely obscured by the apparent neutrality of the geometrical representa- tion used in linear perspective. The axiomatic nature of geometric opera- tions and their seeming autonomy make it easy, particularly for a modern interpreter, to forget the conditions under which such operations took form or could be taken as truly representing anything. My earlier discussions of geometry and its role in medieval optics have anticipated this problem but more needs to be said, particularly about the assumptions on which the most decisive steps in the development of linear perspective, including the contribution of Brunelleschi and his costruzione legittima,were based.

The conventional interpretations, which take for granted that linear perspective is a new representation of space, make sense only in the modern Newtonian world, where space is seen as absolute and as an independent, a priori concept. It is true, of course, that perspective ideally anticipates such space, but in the fifteenth century space is still part of a phenomenal reality in which it cannot be treated in isolation from the conditions of its embodi- ment. After all, artificial perspective was never supposed to be a purely mathematical or absolute discipline but a pictorial one, representing not a concept of space or abstract structure but a concrete world in its visibility. In such a world, space is both articulated and also embodied and situated, which means that it always has a situational structure as a background to all possible transformations.94_{The development of perspectival representa-}

tion was closely linked not only with medieval optics, new treatments of proportions, and the imaginary or ideal structure of design (lineamenti) but also with surveying, geography, and, most of all, the development of the pictorial space in artists’ workshops. The practice of the workshops is par- ticularly important, because it was there that the creative steps of synthe- sis occurred.95

The first signs of the change toward a new type of pictorial space can be seen in the works of Giotto, of his older and younger contemporaries (Cavallini, Cimabue, and Duccio), and of his disciples (Taddeo Gaddi). Changes in the interpretation of space always result from a more fundamental alter- ation in the intellectual life and sensibility of a particular epoch, and thus these shifts cannot be understood in isolation or as simply formal problems.

The Presentation of the Virginby Taddeo Gaddi in Santa Croce in Florence well illustrates such a change in the period of transition from medieval to proper Renaissance representation (figure 3.12). The composition of the painting, dominated by an oblique construction of a temple, is treated in a medieval manner; individual scenes and places are configured in relation to their meaning and not to a unifying space. This approach is underscored by the lack of any clear connections between figures and their surrounding or between themselves, and there is no unity of event, time, and place. Realis- tic unity or unifying space remains problematic in a world structured in ac- cordance with symbolic topology, where imaginative and not descriptive space is important.

However, the growing emphasis on the concrete representation of di- rectly visible reality, on the realistic interpretation of details and of human figures, contributed decisively to the emergence of a new space. Corporeal- ity became important, with all its typical characteristics—modeling and vol- ume, incidental light and shadow, and so on—simultaneously defining body and space. The new interest in a more precise definition of corporeality led also to a new, almost mathematically clear relation between the body’s vol- ume, its surface, and space. This mathematical clarity is most apparent in the geometry of the depicted architectural structures (casamenti) and ob- jects. As a paradigm of embodiment and spatiality, architecture became a prime, dominating element in the formation of the new pictorial space and in the process of “perspectivization.” What gave architecture such a privi- leged position was its idealized, quasi-mathematical nature—the main characteristic of perspective itself.

Architecture and perspective share a sense of coherent space, most clearly exemplified in the concept of a “room.” The space of a room is obvi- ously not the same as the phenomenal space of the natural world. It is a highly idealized representation that during its long history acquired many of the characteristics of the isotropic space of geometry. The natural per-

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spectivity of architecture is already anticipated in the prevailing parallelism of columns, pillars, and walls, as well as in the axiality and overall regular- ity of its spatial arrangement.

It is true that perspectival depth can be represented by other nonlin- ear means, such as light, shadow, and color, or by perspectival foreshorten- ing of the figures; but in those cases, too, the sense of room seems to play a decisive role. Consider Altichieri da Zevio’s Crucifixion,which offers an un- usual interpretation of space structured mostly by human figures (figure 3.13). Even here, however, the depth of the scene is defined by architectural