This article seeks the origin, in the theories of Ibn al-Haytham (Alhazen), Descartes, and Berkeley, of two-stage theories of spatial perception, which hold that visual perception involves both an immediate representation of the proximal stimulus in a two-dimensional ‘‘sensory core’’ and also a subsequent perception of the three dimensional world. The works of Ibn al-Haytham, Descartes, and Berkeley already frame the major theoretical options that guided visual theory into the twentieth century. The field of visual perception was (...) the first area of what we now call psychology to apply mathematics, through geometrical models as used by Euclid, Ptolemy, Ibn al-Haytham, and Descartes (among others). The article shows that Kepler’s discovery of the retinal image, which revolutionized visual anatomy and entailed fundamental changes in visual physiology, did not alter the basic structure of theories of spatial vision. These changes in visual physiology are advanced especially in Descartes' Dioptrics and his L'Homme. Berkeley develops a radically empirist theory vision, according to which visual perception of depth is learned through associative processes that rely on the sense of touch. But Descartes and Berkeley share the assertion that there is a two-dimensional sensory core that is in principle available to consciousness. They also share the observation that we don't usually perceived this core, but find depth and distance to be phenomenally immediate, a point they struggle to accommodate theoretically. If our interpretation is correct, it was not a change in the theory of the psychology of vision that engendered the idea of a sensory core, but rather the introduction of the theory into a new metaphysical context. (shrink)

The Age of Enlightenment is more global and complex than the standard Eurocentric Colonial Canon narrative presents. For example, before the advent of unscientific racism and the systematic negligence of the contributions of Others outside of “White Europe,” Raphael centered Ibn Rushd (Averroes) in his Vatican fresco “Causarum Cognitio” (1511); the astronomer Edmund Halley taught himself Arabic to be more enlightened; The Royal Society of London acknowledged the scientific method developed by Ibn Al-Haytham (Alhazen). In addition, if we (...) study the Transatlantic texts of the late 18th century, it is not Kant, but instead enlightened thinkers like Anton Wilhelm Amo (born in present-day’s Ghana), Phillis Wheatley (Senegal region), and Toussaint L’Ouverture (Haiti), who mostly live up to the ideals of reason, humanism, universalism, and human rights. One obstacle to developing a more balanced presentation of the Age of the Enlightenment is the influence of colonialism, Eurocentrism, and methodological nationalism. Consequently, this paper, part II of two, will also deal with the European Enlightenment’s unscientific heritage of scholarly racism from the 1750s. It will be demonstrated how Linnaeus, Hume, Kant, and Hegel were among the Founding Fathers of intellectual white supremacy within the Academy. Hence, the Age of Enlightenment is not what we are taught to believe. This paper will demonstrate how the lights from different “Global Enlightenments” can illuminate paths forward to more dialogue and universalism in the 21st century. (shrink)