Instinct and Intuition

"Most of entrepreneurship, for me, is about instinct and intuition. Many times I have been asked by someone considering a new venture if he should go for it. But an entrepreneur knows instinctively when to go for it." Michael Dell from Dell Computers.

There is written in a lot of books that Instinct is something that we are born with; it is something that we do naturally without thinking. Instincts are generally an inherited pattern of responses or reactions to certain kinds of situations, and can be seen as a reaction. The word "intuition" can be seen as the direct perception of meaning or truth, without conscious reasoning, but, both words suggest us the idea that some amount of knowledge and awareness is involved, but how reliable are our instincts and intuition?
Instinct and intuition are two attributes that don't fit the scientific mold and are very hard to measure. Yet they are vital in order to create real entrepreneurship.