A 'simple physical feeling' entertained in one subject is a feeling for which the initial datum is another single actual entity, and the objective datum is another feeling entertained by the latter actual entity.
Thus in a simple physical feeling there are two actual entities concerned. One of them is the subject of that feeling, and the other is the initial datum of the feeling. A second feeling is also concerned, namely, the objective datum of the simple physical feeling. This second feeling is the 'objectification' of its subject for the subject of the simple physical feeling. The initial datum is objectified as being the subject of the feeling which is the objective datum: the objectification is the 'perspective' of the initial datum.
A simple physical feeling is an act of causation. The actual entity which is the initial datum is the 'cause/ the simple physical feeling is the 'effect/ and the subject entertaining the simple physical feeling is the actual entity 'conditioned' by the effect. This 'conditioned' actual entity will also be called the 'effect.' All complex causal action can be reduced to a complex of such primary components. Therefore simple physical feelings will also be called 'causal' feelings.
But it is equally true to say that a simple physical feeling is the most primitive type of an act of perception, devoid of consciousness. The actual entity which is the initial datum is the actual entity perceived, the objective datum is the 'perspective' under which that actual entity is perceived, and the subject of the simple physical feeling  is the perceiver. This is not an example of conscious perception. For the subjective form of a simple physical feeling does not involve consciousness, unless acquired in subsequent phases of integration. It seems as though in practice, for human beings at least, only transmuted feelings acquire consciousness, never simple physical feelings. Consciousness originates in the higher phases of integration and illuminates those phases with the greater clarity and distinctness.
Thus a simple physical feeling is one feeling which feels another feeling. But the feeling felt has a subject diverse from the subject of the feeling which feels it. A multiplicity of simple physical feelings entering into the propositional unity of a phase constitutes the first phase in the concrescence of the actual entity which is the common subject of all these feelings. The limitation, whereby the actual entities felt are severally reduced to the perspective of one of their own feelings, is imposed by the Gategoreal Condition of Subjective Unity, requiring a harmonious compatibility in the feelings of each incomplete phase. Thus the negative prehensions, involved in the production of any one feeling, are not independent of the other feelings. The subjective forms of feelings depend in part on the negative prehensions. **This primary phase of simple physical feelings constitutes the machinery by reason of which the creativity transcends the world already actual, and yet remains conditioned by that actual world in its new impersonation. **
Owing to the vagueness of our conscious analysis of complex feelings, perhaps we never consciously discriminate one simple physical feeling in isolation. But all our physical relationships arc made up of such simple physical feelings, as their atomic bricks. Apart from inhibitions or additions, weakenings or intensifications, due to the history of its production, the subjective form of a physical feeling is re-enaction of the subjective form of the feeling felt. Thus the cause passes on its feeling to be reproduced by the new subject as its own, and yet  as inseparable from the cause. There is a flow of feeling. But the re-enaction is not perfect. The categoreal demands of the concrescence require adjustments of the pattern of emotional intensities. The cause is objectively in the constitution of the effect, in virtue of being the feeler of the feeling reproduced in the effect with partial equivalence of subjective form. Also the cause's feeling has its own objective datum, and its own initial datum. Thus this antecedent initial datum has now entered into the datum of the effect's feeling at second-hand through the mediation of the cause.
The reason why the cause is objectively in the effectt is that the cause's feeling cannot, as a feeling, be abstracted from its subject which is the cause. This passage of the cause into the effect is the cumulative character of time. The irreversibility of time depends on this character.
Note that in the 'satisfaction' there is an integration of simple physical feelings. No simple physical feeling need be distinguished in consciousness. Physical feelings may be merged with feelings of any type, and of whatever complexity. A simple physical feeling has the dual character of being the cause's feeling re-enacted for the effect as subject. But this transference of feeling effects a partial identification of cause with effect, and not a mere representation of the cause. It is the cumulation of the universe and not a stage-play about it. In a simple feeling there is a double particularity in reference to the actual world, the particular cause and the particular effect. In Locke's language (III, III, 6), and with his limitation of thought, a simple feeling is an idea in one mind 'determined to this or that particular existent.' Locke is here expressing what only metaphysicians can doubt.
By reason of this duplicity in a simple feeling there is a vector character which transfers the cause into the effect. It is a feeling from the cause which acquires the subjectivity of the new effect without loss of its original
 subjectivity in the cause. Simple physical feelings embody the reproductive character of nature, and also the objective immortality of the past. In virtue of these feelings time is the conformation of the immediate present to the past. Such feelings are 'conformar feelings.
The novel actual entity, which is the effect, is the reproduction of the many actual entities of the past. But in this reproduction there is abstraction from their various totalities of feeling. This abstraction is required by the categoreal conditions for compatible synthesis in the novel unity. This abstractive 'objectification' is rendered possible by reason of the 'divisible' character of the satisfactions of actual entities. By reason of this 'divisible' character causation is the transfer of a feeling, and not of a total satisfaction. The other feelings are dismissed by negative prehensions, owing to their lack of compliance with categoreal demands.
A simple physical feeling enjoys a characteristic which has been variously described as 're-enaction/ 'reproduction/ and 'conformation/ This characteristic can be more accurately explained in terms of the eternal objects involved. There are eternal objects determinant of the definiteness of the objective datum which is the 'cause/ and eternal objects determinant of the definiteness of the subjective form belonging to the 'effect/ When there is re-enaction there is one eternal object with two-way functioning, namely, as partial determinant of the objective datum, and as partial determinant of the subjective form. In this two-way role, the eternal object is functioning relationally between the initial data on the one hand and the concrescent subject on the other. It is playing one self-consistent role in obedience to the Category of Objective Identity.
Physical science is the science investigating spatio-temporal and quantitative characteristics of simple physical feelings. The actual entities of the actual world are bound together in a nexus of these feelings. Also in the creative advance, the nexus proper to an antecedent  actual world is not destroyed. It is reproduced and added to, by the new bonds of feeling with the novel actualities which transcend it and include it. But these bonds have always their vector character. Accordingly the ultimate physical entities for physical science are always vectors indicating transference. In the world there is nothing static. But there is reproduction; and hence the permanence which is the result of order, and the cause of it. And yet there is always change; for time is cumulative as well as reproductive, and the cumulation of the many is not their reproduction as many.
This section on simple physical feelings lays the foundation of the treatment of cosmology in the philosophy of organism. It contains the discussion of the ultimate elements from which a more complete philosophical discussion of the physical world— that is to say, of nature— must be derived. In the first place an endeavour has been made to do justice alike to the aspect of the world emphasized by Descartes and to the atomism of the modern quantum theory. Descartes saw the natural world as an extensive spatial plenum, enduring through time. Modern physicists see energy
transferred in definite quanta. This quantum theory also has analogues in recent neurology. Again fatigue is the expression of cumulation- it is physical memory. Further,! causation and physical memory spring from the same root: both of them are physical perception. Cosmology must do equal justice to atomism, to continuity, to causation, to memory, to perception, to qualitative and quantitative forms of energy, and to extension. But so far there has been no reference to the ultimate vibratory characters of organisms and to the 'potential' element in nature.