One of the earliest concepts in the history of visual perception is the possibility of seeing due to eidolons (Fig. 3), small copies of real objects, consisting of small, indivisible particles called atomos, which fly into the eyes. The Presocratic philosopher Democritus (c. 460-371 BC) was convinced of this idea because he saw the reflection of such objects on the surface of the cornea.6 He also was convinced, that there are two kinds of knowledge existing, one through the senses and the other through the intellect.7
Platon was convinced that the eyes beam a ray like a scanner on the objects of reality (Fig. 4). It was Aristotle who assumed that only shiny objects like fire or the sun produce light, which is reflected by objects and which reflections reach the eyes (Fig. 5).
It took centuries till the Arabic scholar Abu Ali al-Hasan Ibn al-Haytham investigated the anatomical structure of the eye (Fig. 6). Between 1011 and 1021 he wrote the famous Book of Optics which confirmed the assumptions of Aristotle, that seeing is possible because of rays of light.
But „Alhazen“ as the western historians called Ibn al-Haytham, was also engaged in neuropsychological aspects of visual perception. He noticed that seeing happens more likely in the brain than in the eyes. And everything one sees, he supposed, is influenced by personal experiences.8
Even though no new concept for visual perception has been developed till Copernicus, Kepler, or Descartes, Alhazen's Book of Optics was a long time the only accepted theory and a very important key for the development of the central perspective in the Renaissance.9
It took more than 500 years till Johannes Kepler found some answers to questions of the diffraction of light, which had been unsolved by Alhazen. In 1604 he published Astronomiae Pars Optica (Fig. 12–14), where he analyzed the inverted and reversed projection of images by the human eye lens onto the retina.
Galileo Galilei refers to Kepler's achievements in his development of a refracting telescope. The possibility to boost the human eye with the help of optical instruments is an important step in the development of perception and the change of view on the world. When Galilei published 1610 his observations of the Jupiter moons in the book Sidereus Nuncius (Fig. 16) he reinforced the investigations of Nicolaus Copernicus brought to the public 67 years before.
In the year 1543 Copernicus's book De revolutionibus orbium coelestium (Fig. 9) had been published right after his death. He knew that the leading political system, which had been powerfully connected with the catholic system, could not accept his heliocentric model of the universe. Galilei knew that the Copernicus system is inexorable and the religious interpretation of universal processes was no longer arguable.
René Descartes treatise on light Traité du monde et de la lumiére, written between 1629 and 1633 (Fig. 17), disseminates a nearly complete methodological, philosophical, biological, physical and metaphysical interpretation of the „idea, that is formed in our imagination through the intermediary of our eyes“.10 It is the beginning of the modern era and the interaction of several substantial polymaths fusing the existing knowledge of their time.
Descartes as well as Galilei were friends of Christantijn Huygens, a Diplomat and advisor of the House of Orange-Nassau, and the father of the Dutch polymath Christiaan Huygens. Christiaan Huygens treatise on light Traité de la Lumière published 1690 (Fig. 20), described that all points of a wavefront of light may be regarded as new sources of wavelets, that expands in every direction.11
Four years before Descartes died (1650), Gottfried Wilhelm Leibniz 1646, and another four years earlier Isaac Newton was born in 1642. Through the vast correspondence of Christiaan Huygens (born 1629), it is known that Huygens met Newton in London 1689, and became a friend of Leibniz in Paris some years later. The connections and rivalries of the polymaths of these times changed the interpretation and the perception of the world.
One example is the lifelong interest of Leibniz to develop a universal relevant language (Characteristica universals), which boosted the development of the binary system, the basis of any existing computer system (cf. Fig. 22 & 23).12 Newtons detection of different spectral hues overturned a century-old dogma of „pure“ light, which was assumed to be white. Though Johann Wolfgang von Goethe defended the Aristotelian theory of the fundamental nature of white light in his Farbenlehre (1810, Fig. 27), Newton’s particle theory of light in his book Opticks (1704, Fig. 24), was the beginning of a completely new understanding of light.
In the middle of the 18th century, not only the physical understanding of light and the way humans can see had been changed. The philosopher Alexander Gottlieb Baumgarten published 1750/58 Aesthetica (Fig. 25), a theory of beauty, established perception as an independent science in humanities. Although he connected the term aesthetics with the concept of human sensations „as the ultimate ground of judgment in questions pertaining to beauty.“13 With this book the philosophical discussion of aesthetics started and not at some remote period, 1781, Immanuel Kant reacted to Baumgarten’s publication with the statement that aesthetic could never contain „objective rules, laws or principles of natural or artistic beauty“.14 Kant stated nine years later in his Critique of Judgement (Fig. 26), that an aesthetic judgment has to be subjective. Arthur Schopenhauer countered Kant, that he „does not start from the beauty itself, from the direct, beautiful object of perception, but from the judgment concerning the beautiful…“.15
Parallel to the philosophical dispute a further development arose, which should change the perception and the view of the world again. In the late 18th century James Watt patented a steam engine with a continuous rotary motion.16 The beginning of the industrial revolution stimulated the investigation of moving images. Michael Faraday published in 1831 (Fig. 31) an essay on a peculiar Class of Optical Deceptions.17 He observed the optical phenomenon of two wheels moved in opposite directions with equal velocity. The Belgian physicist Joseph Plateau featured 1832/33 the same effect with a device called phenakistoscope, which demonstrates the illusion of a moving image by counter-rotating disks with repeating drawn images in small increments of motion on one and regularly spaced slits on the other disk (Fig. 32). 1833/34 the Viennese professor for geometry Simon Stampfer invented the stroboscopic disk, which showed a series of images on one side separated by slits (Fig. 33). When the disk was held and rotated in front of a mirror, the images appeared to move when watched through the slits.18
Years later the Austrian physicist and philosopher Ernst Mach became famous for his study of shockwaves and in the field of supersonic fluid mechanics. But his initial studies were based in the field of experimental physics and the investigation of the interference, diffraction, polarization, and refraction of light in different media under external influences. He defended phenomenalism recognizing only sensations as real19 and all knowledge as a conceptual organization of data of sensory experience or observation (Fig. 41).20 Machs rigorous criteria of metaphysical concepts of absolute time and space (like Newton suggested) prepared the way for Einstein's relativity theory.
Albert Einstein extended a hypothesis from Max Planck, who suggested that the emission of radiation is not continuously happening but in discrete packets, called quanta (cf. Fig. 45).21 Einstein investigated the interaction of matter and light by explaining the emission of electrons on a metal surface irradiated by light or higher-energetic photons. The photoelectric effect was based on the concept that light is composed of photons and that an atom in a metal can absorb either a whole photon or nothing (Fig. 46).
Nine years before Einstein´s theory appeared a theory by the physiologist Sigmund Exner published 1894 which claimed that perception is a complex excitement triggered by consciousness.22 Exner outlined the idea, that the inner representation of the world is possible by the network of neuronal regions in the brain (Fig. 42 & 43). Exner already recognized the basic idea of the cognitive neurosciences and opened the door to the psychological aspect of perception, which had been discussed four years earlier by the philosopher and founder of the Gestalt psychology Christian von Ehrenfels in his essay Über Gestaltsqualitäten (On the Qualities of Form) 1890. Ehrenfels was convinced of the quality of perception of the whole, compared to its parts. Alexius Meinong, who had been Ehrenfels´ dissertation adviser in Graz, specified the Gestaltvorstellung (figure imagination) as the result of a psychological act as a product of imagination (Vorstellungsprodukt). Together with Stephan Witasek and Vittorio Benussi the Graz School of Experimental Psychology represented a subjective creation of Gestalten (figures), which is added to the complex of perception as a second or higher level. In contrast, the Berlin School of Experimental Psychology with Max Wertheimer, Wolfgang Köhler, Kurt Koffka stated a figure (Gestalt) as a primary object.23
From the development of perception as an inner image of the outer world and from the Gestalt theory to cognitive psychology, it was obvious that perception is an important part of a mental process next to attention, language use, memory, problem-solving, creativity, and thinking.24
The mathematician and philosopher Norbert Wiener developed a transdisciplinary psychological approach of perception into a regulatory system subsuming as cybernetics (Fig. 56) in 1948.25 While the term still remains an understanding of technological control of any system, Heinz von Foerster developed Wieners concept to the second-order cybernetics, referring to biological processes. Founding the Biological Computer Laboratory in 1958, he investigated self-organizing systems, observing systems, cognitive processes in perception and developed with additional parts of physiology, information theory, perception theory, technology, and epistemology a further branch of constructivism.26, 27 Foersters comprehensions of constructivism entangles an observer indivisible with the observed within a system.28
Parallel to Norbert Wiener the mathematician and electrical engineer Claude Shannon published in 1948 A Mathematical Theory of Communication (Fig. 55).29 This paper provided the concepts, insights, and mathematical formulations that now form the basis of modern communication technology and are widely received as the beginning of information theory and the emerging information age.30
In art images always had been the central topic in depicting the world. The perception of images equaled symbolic markers indicating places and objects of hunting or religious acts. In the development of the central perspective in the renaissance (cf. Fig. 10 & 15), a window had been opened, which imitated reality so apparent to the world of matter, that the imaginary interpretations of these constructed worlds did not attract further attention.
In the scientific study of sight and the behavior of light, images became more and more representative of developed knowledge. The industrial revolution brought forward the studies of moving images and the reflection of perception in physiological and psychological disciplines. The act of seeing became an autonomous expression of art. The development of technical devices to sharpen the perception changed the view of the world. Peter Weibel called this machine perception (apparative Wahrnehmung).31 Alfons Schilling, Walter Pichler, Oswald Wiener, Max Peintner, and Peter Weibel developed in the 60s series of artworks elaborating this questions of perception by machine influence and if „reality had been always a virtual reality“.32
With augmented reality, tangible reality is virtual reality. Or at least it can be taken for real through augmented perception (cf. Fig. 72). With this development, the view of the world changed not the first time. Mass media, the first image from the moon onto the earth (Fig. 60), the worldwide web pushed humanity forward similar to the period in time when the first microscopes and telescopes were built.
While in the 15th and 16th centuries central perspective enabled a photorealistic depiction of nature, it also developed somehow an egocentric perspective, while the geocentric perspective changed into a heliocentric one. The technical possibility to take pictures and to distribute them easily promotes a decentralized perspective in the 21st century. But this process creates so much data, like never before 2013 in the whole of humanity. Without artificial intelligence no augmented reality is possible. And in the rush of time, the developments can not follow a linear protocol any longer.
As always, only a small excerpt from the sum of events can be described. While a fairly linear narrative seems possible until the cognitive turn, the flow of information intensifies enormously in the 20th and early 21st centuries. However, it can be noted that in the understanding of perception, the view of the world is implied. It would therefore be presumptuous to assume that only one worldview exists for all people. This contradicts any notion of diversity within a species. But there are certain unifying perspectives that apply even when it is unclear where the path leads. From the continuing illustration, at least, it is apparent that many developments revolve around a public perception that points to a collective body.
Even if this brief historical outline is structured chronologically as far as possible, it is difficult to describe the variety of parallel events. This overview, therefore, makes no claim to completeness. It demonstrates that after the establishment of technical aids for the expansion of human perception, phases of an intensive exchange of information begin. This allows existing structures to be viewed and reflected on in a new way. And this often causes social reconstruction, riots, uprisings, and sometimes even war. Like the Thirty Years' War some years after the development of the telescope. Or looking at World War I, some years after the first telephone connections had been established and the radio went on air. Such occurrences always mark the end of an outdated worldview and a new beginning.