Modern psychologists tell us that all reasoning begins in perplexity, hesitation, doubt. “The process of reasoning is one of problem solving. . . . The occasion for the reasoning is always a thwarted purpose.”[2] It is essential we keep this in mind. It differs from the popular conception even more than may appear at first sight. _If a man were to know everything he could not think._ Nothing would ever puzzle him, his purposes would never be thwarted, he would never experience perplexity or doubt, he would have no problems. If we are to conceive of God as an All-Knower, we cannot conceive of Him as a Thinking Being. Thinking is reserved for beings of finite intelligence. Were we to study the origin and evolution of thinking, we would doubtless find that thinking arose in just this way—from thwarted purposes. If our lives and the lives of our animal ancestors had always run smoothly, if our every desire were immediately satisfied, if we never met an obstacle in anything we tried to do, thinking would never have appeared on this planet. But adversity forced us to it. Tickle a frog’s left leg, and his right leg will immediately fly up and scratch it. The action is merely what psychologists would call a “reflex.” Absolutely no thinking takes place: the frog would do the same thing if you removed its brain. And if you tickle its right leg its left leg would fly up to scratch. But if you tickled both legs at once they could not both fly up and scratch each other. It would be a physical impossibility. Here, then, is a difficulty. The frog hesitates; thinking steps upon the scene. After mature deliberation the frog solves his problem: he holds his left leg still while he scratches it with his right, then he holds his right leg still and scratches that with his left. We cannot, then, think on “general principles.” To try this is like attempting to chew laughing gas. To think at all requires a purpose, no matter how vague. The best thinking, however, requires a definite purpose, and the more definite this purpose the more definite will be our thinking. Therefore in taking up any special line of thought, we must first find just what our end or purpose is, and thus get clearly in mind what our problems are. Advising a man to ask himself what his problems are may seem absurd. But it is just this confusion as to what they want to know which has driven men into error time and time again. The history of the never-ending philosophical controversy between “materialism” and “idealism” is largely a history of different ways of stating the issue; the progress made is mainly due to the increasing definiteness with which it has been stated.