Back in high school, I learned about Plato's allegory of the cave and his concept of philosopher kings. Basically, PKs are able understand universal truths (Plato calls them "forms.") A PK, for example, knows true beauty whereas Joe-Toga-and-Sandals can only see instances of beauty.
This seems very similar my idea of the purpose of the design process. Let's say a company asks me to design product X. It isn't my job to just make it pretty, or appealing, or functional, or marketable, or profitable. A successful designer uses process as a method of problem solving to simultaneously fulfill all of these needs. Initially, there is no way to know what makes the best product X. But, through research, ideation, exploration, etc. designers can find rational, justifiable answers that lead to a complete understanding of product X. With that knowledge we are able to create the best product X possible.
It is impossible to find every truth in every (or possibly any) design problem, but we use process to get as close as we can. Since we aren't philosopher kings and can't just see them, the design process is our way of arriving at Plato's forms.