Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
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etween primary <strong>and</strong> secondary sensory qualities. According to Galilei – <strong>and</strong><br />
later to John Locke (Locke 1975, pp 135–141) – primary characteristics, such<br />
as hardness, mass <strong>and</strong> extension in space <strong>and</strong> time are properties of objects,<br />
whereas secondary characteristics, such as colour, texture <strong>and</strong> shape, are<br />
produced by the mind. Galilei thought that “colours – – are no more than<br />
mere names so far as the object in which we locate them are concerned, <strong>and</strong><br />
that they reside in consciousness. Without a living creature experiencing<br />
them, they would not be there.” (Galilei 1957, p 274).<br />
RENÉ DESCARTES 15 points out that our senses often deceive us <strong>and</strong> that this is<br />
the reason why they cannot give us full certainty. His doubt principally concerns<br />
the ability of the senses as such to give us any knowledge about the<br />
world at all; he considers all perceptions of the outer world as deceptive appearances.<br />
(Descartes 1953, p 95). What we perceive is, however, not guided<br />
by our will, it comes to us involuntarily. According to Descartes, this indicates<br />
an existence of something outside of his mind, <strong>and</strong> thus, an external world.<br />
(Descartes 1953, p 134). The ultimate solution to the problem of the connection<br />
between an outer material world (res extensa) <strong>and</strong> an inner conscious<br />
world (res cogitans) is done referring to a good <strong>and</strong> omniscient God, who<br />
cannot provide human beings with conceptions of the world as mere illusions.<br />
(Descartes 1953, 137–138). Descartes claims – as Locke does – that physical<br />
objects themselves have no colour, only a power or disposition to arouse in<br />
the viewer the idea that objects have special colours. But both of them regard<br />
this “illusion” as natural, unproblematic <strong>and</strong>, in practice, possible to ignore:<br />
to the naïve – not philosophically reflecting – everyday perceivers the objects<br />
have their special colours; it is the nature of perception. A sophisticated perceiver,<br />
however, knows that colour is the power to make us experience the<br />
objects as coloured. (Maund 1995, pp 7–8).<br />
Knowledge beside the world<br />
IMMANUEL KANT 16 takes his starting point from human consciousness <strong>and</strong> the<br />
human world of experience. By introspection he tries to describe the principles<br />
of our conception of the world <strong>and</strong> ignore the outer reality, the world as<br />
independent of how we perceive it. His thesis is that beyond our senses we<br />
have no access to the outer world <strong>and</strong> that knowledge about the world is dependent<br />
on a priori given abilities. (Kant 2004, p 111–112). Experiences of<br />
space <strong>and</strong> time are, a priori, given <strong>and</strong> perceptual <strong>and</strong> not conceptual. (Kant<br />
2004, pp 113–124).<br />
We approach the manifoldness of the external world with what he calls transcendental<br />
consciousness; by representation of space <strong>and</strong> time <strong>and</strong> by a num-<br />
15<br />
French philosopher, 1596–1650<br />
16<br />
German philosopher, 1724–1804<br />
19