Not all differentiated surfaces will have this effect, but I doubt that anything significant can be said about what exactly a surface must be like for it to have this effect. When the surface is right, then an experience with a certain phenomenology will occur, and it is this phenomenology that is distinctive about seeing-in. This distinctive phenomenological feature I call 'twofoldness' because when seeing-in occurs, two things happen: I am visually aware of the surface I look at, and I discern something standing out in front of, or (in certain cases), receding behind something else. (Wollheim: Painting as an Art, p. 46) The above quote also provides a basis for understanding the view of type and token that he developed.

From the above understanding of artistic perception, Wollheim goes on to explain his solution to the main objection to subjectivist views of art; namely his thesis of artistic intentionality. His view of intentionality is based on a standardization of interpretation in art. Wollheim argues that art criticism is essentially a process of retrieval and therefore he argues that it is a reconstruction of the creative process which initiated the artwork. He asserts that an understanding of the artist's intention is essential in the critical assessment of a work of art.

Wollheim also distinguishes between types and universals in artworks. Artworks are types rather than universals for Wollheim. There are some interesting parallels with Wollheim's views on this aspect and Platonic forms and particulars. However, Wollheim points out that the way types are to be understood differs from the perception of universals. Types are where "we correlate a class of particulars with a piece of human invention: these particulars may then be regarded as tokens of a certain type." (ALCARAZ J. 2004) the difference between types and universals is illustrated by the following example from Wollheim.

Whereas the universal Redness is not itself red, the type Union...

The most important aspect from my point-of-view is the non-dualistic notion of "seeing-in" to the artwork. This theory allows for a more inclusive and holistic view of the artwork. Secondly, the emphasis on the intentionality of the artist is also deemed an influential and far-reaching theory. Although there are objections to both these theoretical aspects, they provide the foundation of an important discourse in art theory and philosophy.
Bibliography

ALCARAZ J. INDISCERNIBLE PROPERTIES, DISCERNIBLE ARTWORKS

Postgraduate Journal of Aesthetics, Vol. 1, No. 3, December 2004. Retrieved: April23, 2005. http://216.239.59.104/search?q=cache:K4Ksx69pSYQJ:www.british-aesthetics.org/uploads/Alcaraz.PDF+Richard+Wollheim+physical-object+&hl=en&start=4&client=firefox-a

Alpers Svetlana Artful mind: Svetlana Alpers on Richard Wollheim. ArtForum, May, 2004 Retrieved April 23, 2005. http://www.findarticles.com/p/articles/mi_m0268/is_9_42/ai_n6081693

Ayer, a.J., et al. The Revolution in Philosophy. New York: St. Martin's Press, 1956.

Hyman, John. "Subjectivism in the Theory of Pictorial Art." The Monist 86.4 (2003): 676+.

Lyas, Colin. Aesthetics. London: UCL Press, 1997.

Wollheim, Richard (1980) Art and Its Objects, London: Cambridge Press.

Wollheim, R. (1988). Painting as an Art. Wollheim. Princeton University Press/Thames and Hudson.

The complexity of types and token will only be touched on briefly in relation to the central thesis of this paper.

The prescribed length of this paper does not allow for the extension this discussion