The Science of Unitary Human Beings draws on a vast array of subjects that form its the theoretical underpinning for the conceptual framework. These include, amongst others, anthropology, astronomy, mathematics (Daily et al, 1989), Einsteinian (post-Newtonian) physics (Sarter, 1988a) and philosophy, including, for exampleamongst others, the work of Polanyi and de Chardin (Sarter, 1988b). Such subjects often use terminology in a very specific way and demand a knowledge and understanding of concepts that may be very alien to the European, and indeed American, nurse. It may be possible that this is the reason that the Science of Unitary Human Beings has received little emphasis in European nursing. It is certainly the reason why it has been called an "outrageous nursing theory" (Thompson, 1990), the complexity of which is "difficult to understand" (Daily et al, 1989). However, if an attempt is made to try to understand the Science of Unitary Human Beingsconceptual framework, readers will begin to realize why Rogers has been hailed by some as "a brilliant nurse theorist" and "one of the most original thinkers in nursing" (Daily et al, 1989), without whom it is "difficult to imagine what nursing would look like today" (Barrett, 1990b).

In 1970, Rogers formulated five basic assumptions that describe man and the life process in man (Rogers, 1970). These assumptions or "building blocks" underlay the conceptual framework and consist of the concepts of:

Wholeness - in which the human being is regarded as a unified whole which is more than and different from the sum of the parts.
Openness - where the individual and the environment are continuously exchanging matter and energy with each other.
Unidirectionality - where the life process exists along an irreversible space time continuum.
Pattern and Organization - which identifies individuals and reflects their innovative wholeness.
Sentience and Thought - which states that of all life, human beings are the only ones capable of abstraction and imagery, language and thought, sensation and emotion.

Over the ensuing years, four "critical elements" emerged (Cowling, 1990) that are "basic to the proposed system" (Rogers, 1986). These are energy fields, open systems, pattern and pandimensionality (Rogers, 1991). The final concept, pandimensionality, was previously known as multidimensionality and prior to that, four-dimensionality.

Energy fields are the "fundamental unit of the living and the non-living" (Rogers, 1986). They consist of the human energy field and the environment energy field. The human field is "an irreducible, indivisible, pandimensional energy field identified by pattern and manifesting characteristics that are specific to the whole and which cannot be predicted from knowledge of the parts" (Rogers, 1991). The environmental field is integral with the human field. Each environmental field is specific to its given human field.

Open systems (openness) describe the open nature of the fields, which allow for an interchange of energy and matter between the fields, the preferred terminology being that there is a "continuous process" without the mention of energy or matter (Daily et al, 1994). Pattern is the "distinguishing characteristic of the energy field perceived as a single wave" (Rogers, 1986), which gives identity to the field. Human behaviour can be regarded as manifestations of changing pattern (Alligood, 1989). The pattern is constantly changing and might be regarded as an indication of pain, illness or disease (Wright, 1987).

Pandimensionality describes "a nonlinear domain without spatial or temporal attributes" (Rogers, 1991), an "infinite domain without limit" (Daily et al, 1994).

Such a brief summary of the fundamental basis of the Science of Unitary Human Beings hardly does justice to the concepts outlined and does little to explain them. An outline is necessary however, in order to place in context the key to the conceptual framework, the Principles of Homeodynamics. These principles "postulate a way of perceiving unitary man" (Rogers, 1970) and arise from these previous statements, giving "fundamental guides to the practice of nursing" (Rogers, 1990).

The Principles of Homeodynamics, consist of the three principles of integrality, helicy and resonancy. It is these aspects of the Science of Unitary Human Beings that have had more direct relevance for nursing practice, research and education than the descriptions of man and the life process that has previously been outlined. Integrality, which will be described in greater detail further on, is a statement about the "continuous mutual human field and environmental field process" (Rogers, 1990), suggesting that energy fields pass through one another (Alligood, 1989). Helicy describes the "continuous innovative, unpredictable, increasing diversity of human and environmental field patterns" (Rogers, 1990), the "continuous creative development and evolution of the human-environmental fields" (Gueldner, 1989). Resonancy describes the "continuous change from lower to higher frequency wave patterns in human and environmental fields" (Rogers, 1990). In order to gain a greater understanding of these principles, it is useful to see how other authors have interpreted them in their research and practice.

The Principle of Integrality, where the human field is integral or at one with its environmental field (Schodt, 1989), was studied by McDonald (1986), who stated that if there is a continuous mutual human field and environmental process, changes in one field will bring about changes in the other. In other words, "researchers should be able to demonstrate a relationship between a nurse-initiated modification in a person’s environment and an alteration in that person’s state of being" (McDonald, 1986). In order to examine whether such nursing concepts concepts can be brought down the ladder of abstraction to an operational level (Smith, 1988), McDonald tested whether an alteration in the colour of light (the environmental field) could bring about a reduction in rheumatoid arthritis pain in the left hands of 60 female volunteers (human fields) and found that blue lightwaves were related to a reduction in the experience of pain. This comparitively early and rigorously designed study showed that a "practical nursing intervention can be derived from Rogers’ abstract system" (McDonald, 1986).