The relationship between the photographic and optical images and time has been the subject of great deal of debate. Despite their differences, what many of these considerations have in common is their focus on the receiver, whether mechanical, biological, social or the memory and imagination of the observer. My aim here is to shift the emphasis from the receiver to the object or vista that is photographed or viewed and to explore how the constraints implied by our modern understanding of (...) the Universe, concerning space and time, impact on the way we perceive photographic and optical images. Viewed from this perspective, photographs can be treated as light projections of sections of the four-dimensional observable world onto two-dimensional spatial photographic or viewing surfaces. I shall show that despite the severe reduction that such projections imply, these modern considerations have the important consequence of bestowing a complex temporality upon optical images, including photographs. This realization dramatically changes the way we view photographs. I give examples of this rich temporality through considerations of terrestrial images – and more significantly images of the Sky, where these temporal effects are far more pronounced. (shrink)

We consider the domain of applicability of general relativity (GR), as a classical theory of gravity, by considering its applications to a variety of settings of physical interest as well as its relationship with real observations. We argue that, as it stands, GR is deficient whether it is treated as a microscopic or a macroscopic theory of gravity. We briefly discuss some recent attempts at removing this shortcoming through the construction of a macroscopic theory of gravity. We point out that (...) such macroscopic extensions of GR are likely to be nonunique and involve non-Riemannian geometrical frameworks. (shrink)

Infinity, in various guises, has been invoked recently in order to ‘explain’ a number of important questions regarding observable phenomena in science, and in particular in cosmology. Such explanations are by their nature speculative. Here we introduce the notions of relative infinity, closure, and economy of explanation and ask: to what extent explanations involving relative or real constructed infinities can be treated as reasonable?

One of the points of principle made by Cartwright is that the fundamental laws do not describe reality because they are always employed together with ceteris paribus clauses, the implication being that ceteris paribus assumptions always have dire consequences. We here wish to offer a dynamical interpretation of ceteris paribus laws in terms of their stability or fragility. On this interpretation, the consequences of ceteris paribus assumptions become concretely dependent on the nature of the laws under consideration and cannot be (...) decided in a blanket fashion a priori. Using insights from nonlinear dynamical systems theory, we shall put forward the idea that any assumption of the general validity or invalidity of ceteris paribus laws amounts to a stability or fragility assumption, respectively. We shall then argue that it is in certain cases possible to relativise the consequences of ceteris paribus assumptions in a concrete way. We shall also indicate briefly how the same principle applies to Cartwright's arguments concerning composition of causes and approximations. Overall, our intention is to suggest a framework within which Cartwright's intuitions about the fundamental laws of physics could be grounded. (shrink)

Photographs and optical images, whatever their contents, are imprints of the electromagnetic waves in the (human) visible range of wavelengths, we refer to as light. Furthermore, they are designed to portray different parts of the visible light in terms of different colours, in analogy with the human eyes, however imperfectly. The world outside our eyes and cameras, however, is permeated by electromagnetic waves with much wider spectrum of wavelengths than those in the visible range. Importantly also, colour is a construct (...) of our eye‐brains: the Universe itself has no colour, independently of us. I ask how does the knowledge of these facts change the way we perceive the colour in optical images and photographs, whatever their relationship to the world in a representational sense may be? By employing three images, with very different origins and vistas ‐ one a direct photograph, the other two synthetically constructed images using real cosmological observations ‐ I demonstrate the extent to which colour in such images can hide the underlying phenomena of which they claim to visually speak, both due to its nature as a coarse-grained visual index, and by being restricted to the visible range. The aim is not to belittle the important role that our (restricted) vision together with our perception of colour have played in the evolution of our species, and still play in the way we relate to the world informationally, aesthetically and emotionally. But rather to show that recognizing the limitations of our vision and complementing it with the knowledge of the phenomena underlying optical images and photographs can allow us to perceive them anew and provide additional tools (both conceptual and visual) to imagine and envision such images outside the bounds of the visible range and colour. (shrink)