When the mind enquiries into the nature of will-power, it becomes a question whether it is a power of the mind, a power of thought, or a power of the brain. Those who cannot see beyond the power of the brain, call it brain-power; those who cannot see beyond the mind, call it a power of the mind. Those who cannot conceive of the existence in man of anything above the feelings, consider will-power to be a power of feeling. A Sufi understands it to be the divine power.