Architecture is one product of an activity called design, and there is no design without a problem. A problem definition is an explicit, written statement of a problem: the gap between the current state and the desired state.
Before we lay out the route to our destination, we have to know where we're going. More often than not, when we ask software developers what problem their product solves, the discussion goes something like this:
What problem are you solving?
"We're trying to become more object-oriented."
No, that's a solution to some problem, not a problem. What problem are you solving?
"Oh, we're using object orientation so we get better reuse."
No: reuse is itself a solution to some problem. What problem are you solving?
"Well, the last project was too costly and we're trying to reduce our costs."
How many alternatives did you consider?
"Well, none. Everyone else is using objects, so we decided to take a low-risk path."
If you recognize your organization in this reasoning, you're hardly alone.
Grandpa Harry always had a sense of purpose when he set out to build something. Whether it was serious (a house for his family), generous (a small railway station for Jim's model railroad set), or whimsical (carving a small wooden puzzle or toy) it was always purposeful. Your projects should probably be purposeful, too. A good problem definition can help point the way.
Many of the principles of problem definition apply in many other microcosms of design. Problems are ...