Design Is One

Hi there,

long time since my last post, but i feel the need to post again to get opinions and inspiration for other sources from my reading.

I recently looked through this book - http://snurl.com/g3h87

and there was a theory that struck a chord with me. I still cannot decide wether i agree of disagree.

“the basic concept is that the discipline of design is one, and if you can design one thing, then you can design everything. The methodology is the same no matter what the subject”

I study Industrial Design at Uni and would like to think that I could branch into many aspects of design, such as fashion or web design.
so thats where i agree with this point, however i feel as though someone in web design would lack an understanding of how to design a product.

How does everyone feel about this and does anybody have any other literature i could read through related to the subject?

(PS - More of the book can be read online here - http://snurl.com/g3i11)