We all appear to ourselves to be thinking all the time during our waking hours, and most of us are aware that we go on thinking while we are asleep, even more foolishly than when awake. When uninterrupted by some practical issue we are engaged in what is now known as a _reverie_. This is our spontaneous and favorite kind of thinking. We allow our ideas to take their own course and this course is determined by our hopes and fears, our spontaneous desires, their fulfillment or frustration; by our likes and dislikes, our loves and hates and resentments. There is nothing else anything like so interesting to ourselves as ourselves. All thought that is not more or less laboriously controlled and directed will inevitably circle about the beloved Ego. It is amusing and pathetic to observe this tendency in ourselves and in others. We learn politely and generously to overlook this truth, but if we dare to think of it, it blazes forth like the noontide sun. The reverie or "free association of ideas" has of late become the subject of scientific research. While investigators are not yet agreed on the results, or at least on the proper interpretation to be given to them, there can be no doubt that our reveries form the chief index to our fundamental character. They are a reflection of our nature as modified by often hidden and forgotten experiences. We need not go into the matter further here, for it is only necessary to observe that the reverie is at all times a potent and in many cases an omnipotent rival to every other kind of thinking. It doubtless influences all our speculations in its persistent tendency to self-magnification and self-justification, which are its chief preoccupations, but it is the last thing to make directly or indirectly for honest increase of knowledge.[2] Philosophers usually talk as if such thinking did not exist or were in some way negligible. This is what makes their speculations so unreal and often worthless. The reverie, as any of us can see for himself, is frequently broken and interrupted by the necessity of a second kind of thinking. We have to make practical decisions. Shall we write a letter or no? Shall we take the subway or a bus? Shall we have dinner at seven or half past? Shall we buy U. S. Rubber or a Liberty Bond? Decisions are easily distinguishable from the free flow of the reverie. Sometimes they demand a good deal of careful pondering and the recollection of pertinent facts; often, however, they are made impulsively. They are a more difficult and laborious thing than the reverie, and we resent having to "make up our mind" when we are tired, or absorbed in a congenial reverie. Weighing a decision, it should be noted, does not necessarily add anything to our knowledge, although we may, of course, seek further information before making it. 4. RATIONALIZING