Our brains take their input from the rest of our bodies. What our bodies are like and how they function in the world thus structures the very concepts we can use to think. We cannot think just anything - only what our embodied brains permit. Thought is mostly unconscious.
Abstract concepts are largely metaphorical.
According to Lakoff, metaphor appears to be a neural mechanism that allows us to adapt the neural systems used in sensory-motor activity to create forms of abstract reason. Anything we can think or understand is shaped by, made possible by, and limited by our bodies, brains, and our embodied interactions in the world. This is what we have to theorize with. He has been a member of the Governing Board of the Cognitive Science Society, President of the International Cognitive Linguistics Association, and a member of the Science Board of the Santa Fe Institute. How the Embodied Mind Creates Mathematics , a study of the conceptual structure of mathematics.