North Whitehead, Alfred – 10 The nature of ‘delusion’
Type of Spiritual Experience
A description of the experience
PART II DISCUSSIONS AND APPLICATIONS
Chapter II The Extensive Continuum
If the familiar correlations between physical paths and the life-histories of a chair and of the animal body are not satisfied, we are apt to say that our perceptions are delusive. The word 'delusive'" is all very well as a technical term; but it must not be misconstrued to mean that what we have directly perceived, we have not directly perceived. Our direct perception, via our senses, of an immediate extensive shape, in a certain geometrical perspective to ourselves, and in certain general geometrical relations to the contemporary world, remains an ultimate fact. Our inferences are at fault.
In Cartesian phraseology, it is a final 'inspectio' (also termed Intuitio') which, when purged of all 'judicium— i.e., of 'inference — is final for belief.
This whole question of 'delusive' perception must be considered later (cf. Part III, Chs. Ill to V) in more  detail. We can, however, see at once that there are grades of 'delusiveness.' There is the non-delusive case, when we see a chair-image and there is a chair. There is the partially delusive case when we have been looking in a mirror; in this case, the chair-image we see is not the culmination of the corpuscular society of entities which we call the real chair. Finally, we may have been taking drugs, so that the chair-image we see has no familiar counterpart in any historical route of a corpuscular society. Also there are other delusive grades where the lapse of time is the main element. These cases are illustrated by our perceptions of the heavenly bodies. In delusive cases we are apt, in a confusing way, to say that the societies of entities which we did not see but correctly inferred are the things that we 'really' saw.
To sum up this account: When we perceive a contemporary extended shape which we term a 'chair’ the sense- data involved are not necessarily elements in the 'real internal constitution' of this chair-image: they are elements— in some way of feeling— in the 'real internal constitutions' of those antecedent organs of the human body with which we perceive the 'chair’. The direct recognition of such antecedent actual entities, with which we perceive contemporaries, is hindered and, apart from exceptional circumstances, rendered impossible by the spatial and temporal vagueness which infect such data.