One of the definitions of imagination is the ability to face and resolve difficulties. Which makes sense given imagination is an integral component of the learning process, from which higher-order thinking skills of analysis, synthesis, and evaluation are subsumed - the essential building blocks of critical thinking. More important however, imagination helps provide meaning to experience and understanding to knowledge; it is a fundamental faculty through which people make sense of the world.*
Think about that for a moment - if you cannot imagine - you will likely, more often that not, be surprised, confused, or baffled about everyday events which occur around you that fall outside normal routine. In essence, you may perceive no reason behind something you experienced. Imagination "is the ability of forming new images and sensations when they are not perceived through sight, hearing, or other senses."*
I am rarely surprised in part, I believe, due to my automatic and constant scenario-running; following potential logical conclusions in an array of possible variables and outcomes. "When facing a situation, `I can't believe this is happening` is not an acceptable answer for a workable solution. Furthermore, why not? We are each responsible for maintaining a general understanding of causality and the role we play in it, or at least the recognition that we could all be faced with situations in which we were not prepared. It would be foolish to coast through life thinking things would never change. The fact that we weren't expecting it is not a sustainable end-game when repeated ad nauseum."*
Constructivism is a learning theory which promotes the ways people create meaning of the world around them by way of a series of individual constructs - different types of filters we choose to place over our realities for the purposes of comprehension. Rounding back to higher-order thinking, one subset, social constructivism, helps teach in part how to provide multiple representations of reality, avoid oversimplification by representing the complexity of the real world, and encourages thoughtful reflection on experiences in order to promote understanding.
The fact that our imagination is fueled in part by our perceptions skirts the frightening waters of belief, covered in exacting detail here. Frightening only if we are unable to process, absorb and apply new knowledge which may conflict with what we think we know - how we expect the world to be, when in fact it may behave differently at times leading to the surprise, confusion or bafflement above. Wikipedia says that imagination differs from belief because belief "endeavors to conform to the subject's experienced conditions or faith in the possibility of those conditions; whereas imagination as such is specifically free." Whatever the outer circumstances, I am ever perceiving inner pattern-forms and using real-world materials to operationalize them. Others may see what is and wonder why; I see what might be and say "Why not?!" Imagination coupled with belief.
Higher-ordered thinking isn't for everyone. Challenging fixed beliefs takes not only courage, but a modicum of comprehension and self-awareness, two things I've been hard-pressed to discover in the general population - everyone thinks they're open-minded...except for that one thing.