Over at Edge.org, a couple scientists (Benjamin K. Bergen and Simone Schnall) mentioned that metaphors are a very powerful explanation of how humans think.
The idea is that you don't just talk about understanding as seeing, you think about understanding as seeing; morality is thought of as cleanliness, affection as warmth, winners are thought of as being in front of others. The abstract is explained via the concrete, something we know, such as seeing, feeling warmth, clean, catching, escaping.
This is why everything is 'like' something else, and why 'its like...' is a great way to explain a new idea. We have a small set of basic things our brains know, assumptions, and these are then the basis for building our more complex thoughts. I think this is important in understanding the problem of consciousness, in that we have certain thoughts are not inferred or reasoned, but rather hard wired. For example, we infer consciousness in others not via first-year philosophy courses, but rather mirror neurons that fire as if we were smiling, etc.
Understanding the origin of our intuitions is helpful in understanding the concepts they relate to. Schnall talks about how we derive meaning fundamentally from analogies with our sense of our bodies. After all, the brain's main job is controlling its body, as over 50% of its neurons are within the cerebellum, the part of the brain that controls our motor activities. So, we all have a very deep, profound understanding of 'hard', 'up', and other sensations. Cognitive operations have arisen to solve certain adaptive challenges of the physical environment, and so embodied metaphors are the building blocks of perception, cognition, and action. People think metaphorically.