Divergent-Convergent-Lateral Thinking

As you write, you need both kinds of thinking: logic and imagination. In other words, lateral thinking: both logic and imagination, thinking "outside" the box.

Divergent Thinking: Using imagination. Also called creative/horizontal thinking, brainstorming. A question leads to ideas.

Convergent Thinking: Using logic. Also called critical/vertical analytical/linear thinking. Facts lead to an answer.

The graphic is by Sylvia Duckworth.