Holism (from Greek ὅλος holos "all, whole, entire") is the idea that systems (physical, biological, chemical, social, economic, mental, linguistic, etc.) and their properties should be viewed as wholes, not just as a collection of parts.
The term Holism was coined by J C Smuts in Holism and Evolution.[3][4] It was Smuts' opinion that Holism is a concept that represents all of the wholes in the universe, and these wholes are the real factors in the universe. Further, that Holism also denoted a theory of the universe in the same vein as Materialism and Spiritualism.[3]:120–121
The derived adjective holistic has been applied to a wide range of fields where they incorporate the concept of holism.

Synopsis of Holism and Evolution
After identifying the need for reform in the fundamental concepts of matter, life and mind (chapter 1) Smuts examines the reformed concepts (as of 1926) of space and time (chapter 2), matter (chapter 3) and biology (chapter 4) and concludes that the close approach to each other of the concepts of matter, life and mind, and the partial overflow of each other's domain, implies that there is a fundamental principle (Holism) of which they are the progressive outcome.[3]:86 Chapters 5 and 6 provide the general concept, functions and categories of Holism; chapters 7 and 8 address Holism with respect to Mechanism and Darwinism, chapters 9-11 make a start towards demonstrating the concepts and functions of Holism for the metaphysical categories (mind, personality, ideals) and the book concludes with a chapter that argues for the universal ubiquity of Holism and its place as a monistic ontology.
The following is an overview of Smuts' opinions regarding the general concept, functions, and categories of Holism; like the definition of Holism, other than the idea that the whole is greater than the sum of its parts, the editor is unaware of any authoritative secondary sources corroborating Smuts' opinions.

Wholes are composites which have an internal structure, function or character which clearly differentiates them from mechanical additions, aggregates, and constructions, such as science assumes on the mechanical hypothesis.[3]:106 The concept of structure is not confined to the physical domain (e.g. chemical, biological and artifacts); it also applies to the metaphysical domain (e.g. mental structures, properties, attributes, values, ideals, etc.)[3]:161

The field of a whole is not something different and additional to it, it is the continuation of the whole beyond its sensible contours of experience.[3]:113 The field characterizes a whole as a unified and synthesised event in the system of Relativity, that includes not only its present but also its past—and also its future potentialities.[3]:89 As such, the concept of field entails both activity and structure.[3]:115

Darwin's theory of organic descent placed primary emphasis on the role of natural selection but there would be nothing to select if not for variation. Variations that are the result of mutations in the biological sense and variations that are the result of individually acquired modifications in the personal sense are attributed by Smuts to Holism; further it was his opinion that because variations appear in complexes and not singly, evolution is more than the outcome of individual selections, it is holistic.[3]:190–192

The whole exhibits a discernible regulatory function as it relates to cooperation and coordination of the structure and activity of parts, and to the selection and deselection of variations. The result is a balanced correlation of organs and functions. The activities of the parts are directed to central ends; co-operation and unified action instead of the separate mechanical activities of the parts.[3]:125

It is the intermingling of fields which is creative or causal in nature. This is seen in matter, where if not for its dynamic structural creative character matter could not have been the mother of the universe. This function, or factor of creativity is even more marked in biology where the protoplasm of the cell is vitally active in an ongoing process of creative change where parts are continually being destroyed and replaced by new protoplasm. With minds the regulatory function of Holism acquires consciousness and freedom, demonstrating a creative power of the most farreaching character. Holism is not only creative but self-creative, and its final structures are far more holistic than its initial structures.[3]:18, 37, 67–68, 88–89

As it relates to causality Smuts makes reference to Whitehead, and indirectly Spinoza; the Whitehead premise is that organic mechanism is a fundamental process which realizes and actualizes individual syntheses or unities. Holism (the factor) exemplifies this same idea while emphasizing the holistic character of the process. The whole completely transforms the concept of Causality; results are not directly a function of causes. The whole absorbs and integrates the cause into its own activity; results appear as the consequence of the activity of the whole.[3]:121–124,126 Note that this material relating to Whitehead's influence as it relates to causality was added in the second edition and, of course, will not be found in reprints of the first edition; nor is it included in the most recent Holst edition. It is the second edition of Holism and Evolution (1927) that provides the most recent and definitive treatment by Smuts.

The whole is greater than the sum of its parts
The fundamental holistic characters as a unity of parts which is so close and intense as to be more than the sum of its parts; which not only gives a particular conformation or structure to the parts, but so relates and determines them in their synthesis that their functions are altered; the synthesis affects and determines the parts, so that they function towards the whole; and the whole and the parts, therefore
reciprocally influence and determine each other, and appear more or less to merge their individual characters: the whole is in the parts and the parts are in the whole, and this synthesis of whole and parts is reflected in the holistic character of the functions of the parts as well as of the whole.[3]:88

Progressive grading of wholes
A "rough and provisional" summary of the progressive grading of wholes that comprise holism is as follows:[3]:109
1. Material structure e.g. a chemical compound 2. Functional structure in living bodies 3. Animals, which exhibit a degree of central control that is-primarily implicit and unconscious 4. Personality, characterized as conscious central control 5. States and similar group organizations characterized by central control that involves many people. 6. Holistic Ideals, or absolute Values, distinct from human personality that are creative factors in the creation of a spiritual world, for example Truth, Beauty and Goodness.