Page:Mind (New Series) Volume 6.djvu/231

 ON THE NATURE OF THE NOTION OF EXTERNALITY. 215 selves. At the same time, by the terms of the theory it is admitted that the perception is conditioned. Further, these mental conditions must be the exclusive means of realising the potential sensations : otherwise the ' existence ' of the object does not imply merely that on the fulfilment of the appropriate mental conditions it "would be perceived". Finally, the conditions must admit of being specified : otherwise there is no meaning in speaking of them as con- ditions. To say that a phenomenon is conditioned, is to say that under certain circumstances, or certain sets of circumstances, it will always happen but only under such circumstances. I have not, as will be readily believed, the slightest in- tention of disputing that certain trains of sensations, etc., if themselves realised, may in point of time lead up to the realisation in sense-perception of the as yet unperceived objects and this even if these trains are completely ir- relevant to the given end. But the above analysis of Apologetic Idealism brings to light the fact that it im- plicitly asserts that the actualised perception follows by rule on the mental states which precede it. In other words, it asserts that the determining factors of perception are, exclusively, mental states. If this is not the meaning of the theory, it is impossible to say what it does mean. Now it has been shown in part i., not merely that there is no routine in perceptions ; but also that, as a matter of psychological fact, we always do distinguish between, on the one hand, the experiences which in point of time lead up to the realisation in sense-perception of any material object or event ; and, on the other hand, the conditions which led to that event taking place, or (supposing it granted that everything has had a history) to that object being as it is, both in respect of its position and its characteristics. Well, if the determining factors of per- ception were exclusively mental states, there would be a routine, if not in perceptions taken alone, at any rate in mental phenomena considered as a whole : and consequently there would never be any need to distinguish in this way between the history of the material thing itself, and the experiences which in point of time lead up to its per- ception. The fact that we actually do employ the notion of externality as a basis for rationalising our perceptual experience, indicates that no more direct method is avail- able. Thus the distinction between the stream of conscious- ness and events in the external world, involves also a