Clarification/Follow-up by tonyrey on 02/05/09 1:47 am:
Our reasoning may be based not on one but several or many fundamental beliefs. Even so our entire view of reality may be false and unbalanced if we don't know what those beliefs are.

A good parallel is the current economic crisis. There are different theories about why it occurred but its immediate causes are not the real problem. The crimes and errors of individuals and institutions presuppose a more fundamental flaw - the vulnerability of financial system.

Similarly, to take the physical world for granted is to ignore the deeper question of its reality. It is not an illusion but how is it related to us? Are thoughts the product of things or vice versa? Or do they co-exist?

Clarification/Follow-up by tonyrey on 02/06/09 5:45 am:
Jim,

Descartes was certainly on the right track because we inevitably begin with our thoughts. Where else? Some have questioned his transition from thoughts to himself. (Hume noted that he couldn't find his "I"!). It seems reasonable enough to me given that a stream of thoughts can hardly exist by themselves. What would connect them? And even more pertinently what would produce them?

The second question can be asked about a thinker, of course, but it is more economical to posit one entity than many. It is also doubtful whether thoughts should be called entities. In addition, the body of a thinker is tangible whereas thoughts are not (but no doubt that view involves more assumptions!).

All in all, I think Descartes's conclusion is the most satisfactory. Not only are there thoughts but also images and sensations in the mass of primary data. They all need to be linked and unified...

Clarification/Follow-up by tonyrey on 02/06/09 3:41 pm:
server,

The achievements of science show that we know a great deal about the physical world but little about intangible reality. The greatest problem is undoubtedly, in my opinion, the nature of personal existence. But I agree with you that insight, intuition and inspiration occur and cannot be explained scientifically. An example is the ability to distinguish good from evil and right from wrong.