Psychology is the Science of Mental Life both of its phenomena and of their conditions. The phenomena are such things as we call feelings desires cognitions reasonings decisions and the like; and superficially considered their variety and complexity is such as to leave a chaotic impression on the observer. The most natural and consequently the earliest way of unifying the material was first to classify it as well as might be and secondly to affiliate the diverse mental modes thus found upon a simple entity the personal Soul of which they are taken to be so many facultative manifestations. Now for instance the Soul manifests its faculty of Memory now of Reasoning now of Volition or again its Imagination or its Appetite. This is the orthodox 'spiritualistic' theory of scholasticism and of common-sense. Another and a less obvious way of unifying the chaos is to seek common elements in the divers mental facts rather than a common agent behind them and to explain them constructively by the various forms of arrangement of these elements as one explains houses by stones and bricks. The 'associationist' schools of Herbart in Germany and of Hume the Mills and Bain in Britain have thus constructed a psychology without a soul by taking discrete 'ideas' faint or vivid and showing how by their cohesions repulsions and forms of succession such things as reminiscences perceptions emotions volitions passions theories and all the other furnishings of an individual's mind may be engendered. The very Self or ego of the individual comes in this way to be viewed no longer as the pre-existing source of the representations but rather as their last and most complicated fruit.

Now if we strive rigorously to simplify the phenomena in either of these ways we soon become aware of inadequacies in our method. Any particular cognition for example or recollection is accounted for on the soul-theory by being referred to the spiritual faculties of Cognition or of Memory. These faculties themselves are thought of as absolute properties of the soul; that is to take the case of memory no reason is given why we should remember a fact as it happened except that so to remember it constitutes the essence of our Recollective Power. We may as spiritualists try to explain our memory's failures and blunders by secondary causes. But its successes can invoke no factors save the existence of certain objective things to be remembered on the one hand and of our faculty of memory on the other. When for instance I recall my graduation-day and drag all its incidents and emotions up from death's dateless night no mechanical cause can explain this process nor can any analysis reduce it to lower terms or make its nature seem other than an ultimate datum which whether we rebel or not at its mysteriousness must simply be taken for granted if we are to psychologize at all. However the associationist may represent the present ideas as thronging and arranging themselves still the spiritualist insists he has in the end to admit that something be it brain be it 'ideas' be it 'association' knows past time as past and fills it out with this or that event. And when the spiritualist calls memory an 'irreducible faculty' he says no more than this admission of the associationist already grants.