Among the activities of scientists, the forming and manipulating of scientific theories is important enough to warrant a discussion of its own. Theory formation is considered by some to be such a unique undertaking that it is the province a privileged few and has no parallels in other endeavours. However, like the scientific method as a whole, theory formation is an example of a broader and relatively common activity whose exercise is necessary for all citizens in a sufficiently complex society. Indeed, the ability to propose theories may be necessary for the formation of such a society in the first place.

The Western Judeo-Christian religious tradition holds that God is capable of holding in his thoughts all the details of the fine structure of the universe simultaneously. This limitless knowledge and creative energy brought the universe into being in the first place, and now holds it together. Although not all agree that God even exists, much less is omniscient and all-powerful in this sense, no one seriously believes it possible for any human being to achieve such a universal awareness. Even mundane and ordinary objects (a chair, a tree, a cow, one human cell) are sufficiently complex to make such a comprehensive understanding impossible. It has been centuries since a single human being could have even a passing acquaintance with all the available academic knowledge, and it is now no longer possible for any person to comprehend the whole of any single discipline. Neither is it correct to assume that everything knowable about a given discipline has already been discovered, or ever will be.

Fortunately, it is not necessary to have such comprehensive knowledge about something in order to make appropriate use of it. One can enjoy a car ride without knowing how to drive. It is not necessary to be able to build an automobile in order to drive one, and not required that the workers building it be able to design it. The designers need not be able to produce the metals and plastics from which it is made. None of these must know how to refine the petroleum products required to run it. Road designers, builders, and mechanics occupy related specialists, and so do the legislators, sales people, auto company executives, parts manufacturers, and many others.

Each of these has different priorities for what they must know about the automobile. For each, there is an essential subset or extract of detail taken from all that it is available to know about the subject. Each views an automobile by focusing only on the details essential to a particular role, and needs only a cursory acquaintance with details important to others.

A similar process is at work in the formation of theories by scientists (and others). Here, it is clearly understood that no object can be comprehended in every detail down to the sub-atomic. It is the concentration on essentials and the exclusion of details that makes understanding manageable, and even possible. Such a process gives a researcher an intellectual handle on the subject that would be impossible if knowing everything were deemed to be the only adequate kind of knowledge. It is therefore possible to conceive of something by knowing an appropriate and sufficient subset of its properties. In this light, it is possible to offer the following definition:

One aspect of abstraction is deciding which properties are the sufficient essentials to the task at hand, and which are details that can be ignored. This decision very much depends on the community within which the abstraction takes place, for to be useful, an abstraction must not only be communicable, it must be communicated. If only one person understands it, but cannot transmit its essence to another, an abstraction has no practical use. Thus, the kinds of abstractions that come to be widely accepted depend on the level of knowledge and education of the community for which they are intended. For instance, a solar-system model for explaining atomic structure is sufficient for those who are not equipped to grasp the finer points of probability and quantum mechanics, but quite inadequate for researchers at the frontier of knowledge in the field. Likewise, there are a variety of models for explaining the workings of a modern economy, and these vary in complexity and usefulness depending on whose understanding is being addressed. The needs of most citizens are quite different from those of a politician making a decision, or those of a professional economist summarizing available information for that decision.

This process of attempting to explain a myriad of detail through an abstraction of certain broad outlines or essentials is not confined to the sciences or even to the academic disciplines that attempt to use the scientific method. Numerous examples are possible from all fields:

o A computer program is an abstraction of a problem solution into a specially devised symbolic language (notation).

o A chart or graph is an abstraction of data or relationships into pictorial form, in order to allow them to be visualized, and therefore understood from a different perspective.

o Words and numbers are symbolic abstractions of specific ideas.

o A language (including a computing notation) is an abstraction designed for the purpose of communicating other abstractions. It could be termed a meta-abstraction.

o Whenever someone learns a skill or a trade, the necessary activities and actions are abstracted from the task details. The skills become automatic, so they can be exercised without thinking about the details.

o The manufacturing/wholesaling/retailing chain is an abstraction that allows people to buy goods without having to make their own.

o All job specialization is a type of abstraction that frees people from excess complication, allows them to concentrate on a small number of useful skills themselves, and to deal with most of the necessities of life through other specialists in a similarly abstract manner.

o Money, whether expressed as precious metal, coin, paper, cheque, or electronically, is an abstraction for the wealth of nations, corporations, and individuals.

o A representative democratic state is an abstraction that allows individual input into the governing process without having to consider every detail of every person's stand on every issue.

o The Judeo-Christian understanding of God is an abstraction for one who is too complex ever to know entirely.

Thus, far from being the province of academics alone, abstraction is a process fundamental to all human activity. The totality of the abstractions used by a culture is an important measure of its complexity. The most sophisticated abstractions are those that allow people to perform complex tasks without much thought. For instance, the graphical interface found on modern computers allows the user to perform very complicated tasks with a minimum of effort (at a higher level of abstraction) by comparison with the verbal interface found on old-fashioned machines. Indeed, all computers are tools for high-level problem-solving--they enable people to make abstractions and avoid detail. Likewise, most industrial machines (and even bicycles) have to be operated abstractly--at a level of unconscious skill, for so long as the details must still be thought about, the task cannot be performed efficiently, if at all. (If you have to think about what you are doing, you fall off your bicycle.)

While one could criticize the process of abstraction over many levels as removing people from "real" understanding, it is precisely such distancing that gives abstractions their power. It is not necessary to understand how cheese is made in order to enjoy it. Neither is it a prerequisite to know how to make or program a computer in order to make productive use of it for such tasks as word processing or data analysis.

These examples illustrate that abstractions are the most useful when they are far removed from the thing being abstracted; when they have been refined to the point that they can be usefully employed by most people in an automatic fashion.

So important and pervasive is the process of abstraction that it has a variety of specialized names arising from different disciplines and from the terminology adopted by the various people who have considered various aspects of this activity. Some of these equivalent terms are mentioned here, because they are of importance in later chapters.

A digest is a summary of that portion of data deemed by the one making the digest to be the most essential. It is an attempt to filter the data, removing the non-essential, redundant, or irrelevant. For instance, data reported from experiments are nearly always digested from the entire set obtained; this is necessary for brevity and clarity.

A Model is a representation of something in a more concrete or accessible form than the original. It may be also used of a scale model for some proposed project. The term conveys the idea of explaining or showing by means of an analogy to something else that is supposedly better understood. (i.e., for which there are believed to be adequate abstractions already). The term modeling may be used by scientists to describe the process of theory formation.

Theory formation is an attempt to abstract into some simple statement the workings of the subject under study. This term tends to be less concrete than modelling, for a theory is an attempt to define rather than to model, though in practice the distinction may be a fine one.

A paradigm is also a way of looking at a subject by way of analogy or example. It too is a model, but this term tends to be used in a broader sense to describe abstractions of considerable importance or size (a collection of related abstractions). One example is the evolutionary paradigm, within which are many models for origins. Another is the Marxists' class struggle, to which view they bend all political science and economics.

A meme is a (perhaps indirectly perceived) transmittable idea that is the basis of a social movement or a political philosophy. Its spread through a population can be studied in a manner similar to that of an infection, because it is the nature of a meme to induce the desire to proselytize. A meme can be benevolent (e.g., the ideals of democracy), fatal to their holders (e.g., the Jim Jones cult beliefs) or fatal to others (e.g., Naziism and Stalinism).

A world view is a complete set of philosophic or religious presuppositions within which paradigms and individual abstractions are formed. It constitutes the total way in which a person does abstractions (thinks) about the real world, and generally finds its expression within the communities of which the person is a member. It encompasses the complete set of memes that a person possesses and spreads. One may speak, for example, of a scientific world view, of a Christian one, of a liberal one, or of an American one. Within each of these there exist numerous specific views of parts of the world.

It would also be instructive in this connection to observe that some media make use of word pictures and of various figures of speech to evoke a much broader point (poetry is like this; so are many aspects of the Bible). Likewise, other media make use of visual pictures to convey a broader message (television commercials are like this). In both cases, a more subtle form of abstraction is being used to transmit actual ideas that are related to or suggested by the formal communication.

The mention of some abstraction term, theory title, or world view name, evokes in the hearer a vision of a set of beliefs, views, or typical activities. That evoked image will invariably be to some degree inadequate or incorrect, especially if the hearer is not a part of the community that devised or is described by the abstraction. When such a misconception takes place, it is often because the hearer holds to some popularly believed ideas about the group in question, in which case the hearer's own (mistaken) abstraction is called a stereotype.

Thus such words as "fundamentalist" or "immigrant" or "liberal" or "Christian" will generate in the hearer a collection of related impressions whose semantic meaning depends on what that person has abstracted under the term in question. This is not to say that the deconstructionists are correct and that no message has an absolute semantic; it is only to observe that communication requires agreement on the meaning of abstractions.

Plants and animals do not make abstractions; this is a uniquely human activity. Abstractions make thinking and communicating possible. They make it possible to understand the world and its processes, whether by science or otherwise. They make it possible to make, to build, to specialize and to cooperate. They are therefore the essential building blocks, not of science alone, but of human civilization itself. This section concludes with an attempt to abstract itself:

Before looking at how the making of abstractions bears on the meaning of science, it is instructive to consider also the relationship between theory and practice.