I'm far behind the threads on intuition and the one on education, but
let my apply my standard rubric:

* When intelligent people disagree, it often turns out that all are
correct -- they are simply talking about different things, or perhaps
the same thing but viewed from a very different perspective.*

I think the argument about the role of intuition versus a systematic
application of knowledge and principles within design is a case in
point. Similarly for the argument about whether or not the PhD in
design is harmful to the field. Let me discuss these briefly.

Intuition versus Systematicity in Design

Some day Roberto Verganti and i will finish our paper in which these
ideas are better developed. Here is how roberto and I discuss this:
Incremental and radical innovation are very different activities.
Incremental is the home for the systematic application of known
knowledge and principles. Radical is the home for "intuition". (Both
are creative.)

Aside: I dislike the word intuition. Intuition means that the person
has no idea where the thought or action has come from. Intuition
requires years of study and practice to acquire in any domain.
However, in this case, it does apply. When someone says "I want to
design this so that it is intuitive to use," I reply, "Oh, you mean
you want the person to spend years learning how to use it."


================
Radical innovation: rare. Where focussed "intuition" applies.

Radical innovation is the most popular and the most talked about,
especially when we talk of creativity. It is, however, the most rare.
Roberto and i contend that the number of radical innovations within
any field is very small. Each of us will only live through a small
number of radical innovations in our lifetime.  Radical innovation is
where the kind of intuition being discussed her shines. It does have
several stages,  as outlined by Birger:

* Preparation: deep thought about a problem coupled with a substantial
period attempting to find a solution. This stage provides the
internalization of much information, knowledge, and skills: this is
called preparation.
* Incubation and Illumination: A period of non-activity, letting the
sub-conscious part of the mind process the information. The
subconscious is a very powerful multi-processor that basically tries
to find stable equilibria (minimum energy configurations). When it
finds one, it signals the conscious mind.  The subconscious part is
called incubation and the signaling is illumination.   These
components were described a long time ago by the mathematician, Henri
Poincare.
* Verification: The subconscious is often wrong. As Poincare put it
(in my words), it can find great novelty, but it doesn't know how to
do arithmetic.  Most of the time, these insights are false.That is why
the stage of verification is needed.

In the world of real design and products, most of these wonderfully
creative radical ideas go nowhere.   It takes more than a good idea to
be successful.

================
Incremental Innovation. The most common. Here is where systematic
approaches apply.

Almost everything we do as designers that have any real value in the
world is an incremental enhancement of what already exists. Here is
where the techniques called "Human-Centered Design" are relevant. here
is where the approach outlined by Terry applies. This is also a
creative process, but different than the radical one.

====
Both radical and incremental innovation can be creative. But they are
two very different activities.

We don't know how to teach radical innovation. Hence, emphasis on
various brainstorming methods (most of which either have no evidence
to support them or have evidence showing they do no good. But they are
a lot of fun, which is why we do them.)  The four stages of
preparation, incubation, insight, and verification have a solid set of
experimental evidence behind them, but they describe the process: they
do not help us make sure it happens.

Although i am a friend and a fan of Cikszentmihailyi, there is no
evidence that his flow state actually leads to great creativity. The
flow state occurs in passive reading or observation of plays,
listening to music, movies, and active participation in computer
games. it does occur in periods of deep thought. It might be a
necessary state for creativity, especially preparation. But again, it
is a description, not an explanation.

===
On a related question; is the PhD harmful to design education?  The
answer is Yes and No, depending upon what aspect of design education
is being considered. One could make a case that they (sometimes) can
be harmful for the training of practitioners. But No -- they are
essential to advance the underlying knowledge base and deep
understanding of design.

Here is an example from my experience as an industry executive (I was
a VP at Apple). We hired PhDs in my research group, but we were very
suspicious of hiring PhDs in the product groups.  Practitioners are
needed to train practitioners. PhDs are need to help advance the
scholarly base of the filed, but most PhDs have very little practical
knowledge: they want to be creative, they want to do deep thinking
about principles and reasons. This is good for the field, but
detrimental to the development and shipping of products.

We need practioners to teach practice and PhDs to teach theory. Both
are needed. It is wrong to question whether one is detrimental to
Design when both are essential.

Don Norman