1. Phenomenalism

2. …  To be is to be perceivable  Problems with Idealism – Commitment to God or to the ‘gappy’ existence of objects Confusion at the heart of the Master Argument Leads to solipsism

3. Re-articulating anti-realism 1. The bounds of knowledge are set by our acquaintance with ideas or sense-data. 2. We can only really have knowledge of our own perceptual experiences. 3. Our talk of physical objects and our perceptual experience of them needs to be cashed out in terms consistent with (1) and (2). Such an analysis must respect the common-sense view that objects continue to exist when unperceived.

4.  In our perceptual experience one does not acquire knowledge of a mind independent world.  The only thing(s) which we can be (directly) aware of (the only possible object of awareness) are complexes/combinations of actual experiences.  The 19th century British empiricist J.S. Mill expressed this point by describing material objects as ‘permanent possibilities of sensation’.

5. …unperceived objects?   When I leave my office the computer and desk continue to exist because were I to return, then I would have just those computer and desk sensations.   Objects are thus to be understood as stable and coherent collections of actual and possible sensations.   A physical object exists as a continuing or permanent possibility of experience. We cannot get knowledge of a world that is independent of our experience or sensations.   Note, this does not entail the Idealist denial that there is a physical reality. It puts a limit set by our perceptual experience on what we can know about the world. .  Unlike the realist, though, the phenomenalist denies that experience warrants going beyond reference to the permanent possibility of sensations to reference to the ground or basis for such a possibility: knowledge of a material world of mind-independent objects.

6. Logical Positivism and Phenomenalism  Phenomenalism is characteristically understood as a semantic thesis.  Statements asserting the existence of physical objects are equivalent in meaning to statements describing sensations.  The phenomenalist claims that to say that a physical object exists is to say that someone would have certain sequences of sensations were they to have certain others.

7. Motivations  It provides a response to sceptical arguments.  Phenomenalism combines this motivating feature of anti- realism with the claim that it is able to retain the sense in which objects exist unperceived.  We can fully explain the meaning of our talk about the external world in verifiable terms of our immediate and possible experience of sense-data.  We can understand our knowledge of the material world as a logical construct of experience.

8. Problems  Can you really translate ordinary experiences of the world into sense-data talk?  Only a weak sense in which it allows that objects continue to exist unperceived.  Correlation between types of perceptual states does not explain why one is in a particular state.  It doesn’t avoid the collapse into solipsism.  What are sense-data?

9.  Key reading –  Knowledge of the External World pp.18-21.  Readings pp. 72-74  So, back to the common-sense of direct realism? direct realismdirect realism