“The photographer’s gesture as the search for a viewpoint onto a scene takes place within the possibilities offered by the apparatus. The photographer moves within specific categories of space and time regarding the scene: proximity and distance, bird- and worm’s-eye views, frontal- and side-views, short or long exposures, etc. The Gestalt of space–time surrounding the scene is prefigured for the photographer by the categories of his camera. These categories are an a priori for him. He must ‘decide’ within them: he must press the trigger.”

Source: The Elementary Forms of the Religious Life, 1912, p. 488

Saul Leiter: The Quiet Iconoclast (2009)

Interview with the Art Newspaper (August 13, 2020)

The Structure of the Universe: An Introduction to Cosmology (1949)
Context: Galileo had raised the concepts of space and time to the status of fundamental categories by directing attention to the mathematical description of motion. The midiaevel qualitative method had made these concepts relatively unimportant, but in the new mathematical philosophy the external world became a world of bodies moving in space and time. In the Timaeus Plato had expounded a theory that outside the universe, which he regarded as bounded and spherical, there was an infinite empty space. The ideas of Plato were much discussed in the middle of the seventeenth century by the Cambridge Platonists, and Newton's views were greatly influenced thereby. He regarded space as the 'sensorium of God' and hence endowed it with objective existence, although he confessed that it could not be observed. Similarly, he believed that time had an objective existence independent of the particular processes which can be used for measuring it.<!--p.46

Variant: to take a photograph is to participate in another person's mortality, vulnerability, mutability. precisely by slicing out this moment and freezing it, all photographs testify to time's relentless melt.
Source: On Photography

On the photograph of Sherpa guide Tenzing Norgay at the summit of Everest, in "Adventure's End" in The Norton Book of Sports (1992) edited by George Plimpton, p. 86
Context: Tenzing had been waiting patiently, but now, at my request, he unfurled the flags wrapped around his ice–axe and standing at the summit, held them above his head. Clad in all his bulky equipment and with the flags flapping furiously in the wind, he made a dramatic picture, and the thought drifted through my mind that this photograph should be a good one if it came out at all. I didn't worry about getting Tenzing to take a photograph of me — as far as I knew, he had never taken a photograph before, and the summit of Everest was hardly the place to show him how.

Deschin, Jacob. "Nature as it is". New York Times (1857-Current file); Feb 3, 1952; Proquest Historical Newspapers The New York Times (1851 - 2002) pg. X14

National Character of Americans—first impressions (1831) Oeuvres complètes, vol. VIII, p. 233 https://books.google.de/books?id=x9pnAAAAMAAJ&pg=RA2-PA233&q=ciel.
Original text:
Né sous un autre ciel, placé au milieu d'un tableau toujours mouvant, poussé lui-même par le torrent irrésistible qui entraîne tout ce qui l'environne, l'Américain n'a le temps de s'attacher à rien; il ne s'accoutume qu'au changement, et finit par le regarder comme l'état naturel à l'homme; il en sent le besoin; bien plus, il l'aime : car l'instabilité, au lieu de se produire à lui par des désastres, semble n'enfanter autour de lui que des prodiges...
1830s

Quote, 1930: from Rodchenko lecture at the October group's meeting; as quoted by Margarita Tupitsyn in Chapter 'Fragmentation versus Totality: The Politics of (De)framing', in The great Utopia - The Russian and Soviet Avant-Garde, 1915-1932; Guggenheim Museum, New York, 1992, p. 486
the issue was not to take 'photo pictures' of the entire object but to make 'photo stills' of characteristic parts of an object