QUOTE : Smee worked both in theory and in the laboratory to explain the electrochemical basis of vision, sensation, memory, logic, and the origination and recombination of ideas. He believed that the mental powers of animals, human beings, and mechanisms were different not in kind but in degree. His definition of consciousness has seen scant improvement in 150 years. “When an image is produced by an action upon the external senses, the actions on the organs of sense concur with the actions in the brain; and the image is then a Reality. When an image occurs to the mind without a corresponding simultaneous action of the body, it is called a Thought. The power to distinguish between a thought and a reality is called Consciousness,” he wrote in his Principles of the Human Mind deduced from Physical Laws, published in 1849.