This article is about the thought experiment called "changing places". To read about the novel by David Lodge, see Changing Places

The changing places thought experiment was created by Max Velmans, Reader of Psychology at Goldsmith's College, University of London, and was discussed in his 2000 work, Understanding Consciousness. The experiment was designed to demonstrate the difficulties in distinguishing phenomenologically between a first-person experience of an event (a subjective experience of an object) and a third-person experience of the same (that is, the analysis of such an experience of an object in a subject). This article is about the thought experiment called changing places. To read about the novel by David Lodge, see Changing Places The changing places thought experiment was created by Max Velmans, Reader of Psychology at Goldsmiths College, University of London, and was discussed in his 2000 work, Understanding Consciousness. ... In philosophy, physics, and other fields, a thought experiment (from the German Gedankenexperiment) is an attempt to solve a problem using the power of human imagination. ... Max Velmans is a Professor of Psychology at Goldsmiths College, University of London. ... Psychology (ancient Greek: psyche = soul or mind, logos/-ology = study of) is an academic and applied field involving the study of mind and behavior. ... Goldsmiths College (founded 1891 by the Worshipful Company of Goldsmiths as Goldsmiths Technical and Recreative Institute) has been a part of the federal University of London since 1904, when it took its current name. ... Senate House, designed by Charles Holden home to the universitys central administrative offices and its library The University of London is a federation of colleges and institutes which together constitute one of the worlds largest universities. ... This article is about the year 2000. ... Look up Phenomenology in Wiktionary, the free dictionary Phenomenology is a current in philosophy that takes the intuitive experience of phenomena (what presents itself to us in conscious experience) as its starting point and tries to extract the essential features of experiences and the essence of what we experience. ...

Velmans conceives of a situation in which an experimenter ("E") is observing the subject ("S") exposed to a light stimulus. The differences between the two viewpoints, Velmans argues, is primarily derived from a difference in interest, reflected in a difference in their required activities. To explain, during the experiment S is required only to report on his experiences of the light, which he needs to communicate to E in an appropriate manner. E, on the other hand, is interested primarily in S's experience of the light, and thus E's focus is not just on the light (which she now thinks of as a "stimulus") but also on the observable events in S's brain, and on S's reports concerning what he experiences. Thus, E is interested first and foremost in the subject's experience, and how these relate to the light stimulus and brain states of S that she can observe. In such a case, E's experience of events would be considered "objective" or "public", while S's experiences are "subjective" and "private"; while E's focus is in recording the neural causes and correlates of visual experiences, S is interested only in reporting about such experiences.

However, Velmans points out that all that would be required for S and E to exchange roles is for them to change their respective foci (as he puts it "S and E merely have to turn their heads"), so that E focuses exclusively on the light and reports her experiences, while S focuses her attention not just on the light, but on the events of E's brain and his reports of the experience. In such an event, S becomes the experimenter and E becomes the subject; thus, following current conventions, "S would now be entitled to think of her observations (of the light and E's brain) as 'public and objective' and to regard E's experiences of light as 'private and subjective'" (Velmans, Understanding Consciousness, 175).

Velmans points out that this outcome is patently absurd, as the phenomenology of the light (that is, its intuited experience) remains the same from the perspective of S or E, that is, whether it is thought of as being an observed stimulus or a subjective experience. Nothing has changed in the nature of the light that either party can observe save in the contextualising focus of their interests. That is, Velmans concludes, there is no phenomenological difference between publicly observed "phenomena" and private, subjective experiences.

See also

• Max Velmans

Max Velmans is a Professor of Psychology at Goldsmiths College, University of London. ...

References

• Velmans, Max, Understanding Consciousness, pp. 175. London: Routledge/Psychology Press. ISBN 0415224926