The world of consciousness has always been seen as the world of the senses but also of course as the world of thought. Although sense-impressions, and in particular images, are the paradigm content of consciousness, it is thought and thinking that constitute its essence. But how can thought be described? If anything, it seems even more puzzling than perception, for the mind seems capable of almost magical feats. In an instant, it can leap any distance and, using its predictive powers, it can defy time and peer into the future. Thought also possesses a strange unpredictable quality. In a flash of inspiration, a problem which has troubled us for days may suddenly become clear, and yet paradoxically, spelling out the solution may take hours, days or even months. So what is it to think? What does thinking actually involve? Despite its importance, it seems impossible to pin down the exact nature of thought: anything we point to seems dead and empty in comparison with the process of thought itself. Similarly, although we may be able to describe a procedure which corresponds to the behaviour of someone acting intelligently, this seems to leave out the essence of the activity. The procedure is
something mechanical, the mere husk of thought-what makes it a manifestation of thought is that it is applied ‘thinkingly’. Thus the essence of thought seems indescribable; it seems the only mystery thought cannot penetrate is its own. These mysteries deepen if we consider the question of what thinking consists of. Here there are only two real candidates-images and inner speech-and each has its virtues. On the one hand, images are undoubtedly involved in some of our thought processes and seem to connect up with other more specific phenomena, e.g. with the flash of insight expressed in the phrase ‘I suddenly saw the solution’. On the other hand, inner speech seems more suited to capture the complexity of thought. Furthermore, although the flash of insight is sometimes contained in an image, it may also take the form of a brief phrase, e.g. when someone pushing against an unyielding door suddenly thinks ‘Why not pull?’ Despite these attractions, both approaches run into difficulties. Take images first. One problem here is the implausibility of claiming that we always experience an image when we think or act in an intelligent way. Someone who is reading, for example, may only experience the odd image, if any, and yet this does not show that reading does not involve thinking. Another problem is that not all thoughts can easily be represented in pictures. This is true not only of abstract ideas but also of everyday thoughts. For example, it is unclear what images correspond to the thought ‘It’s a pity I didn’t stay at the meeting longer because, although it was boring, I might have got the opportunity of having a quiet word with N’. The really fundamental objection, however, is that this approach fails to capture the dynamic quality of thought. In comparison with thought, any picture or image seems dead-in itself it means nothing, for it has to be applied if it is to have a sense. Thus, even if we could see all the images passing through another person’s mind, we still wouldn’t know her thoughts, for we wouldn’t know what she was using those pictures to think. The images, it seems, are not the thoughts, rather the thoughts are what give those images life.