In the previous chapters, and especially in the context of our treatment of propositional knowledge and belief, we have not only talked about 'philosophy', 'ideology' and 'science' but also about 'religion' and 'supernaturalism', about 'scientific knowledge' and 'denominational thought'. When now taking a closer look at the meaning of such terms as science and religion, that is, as used by ourselves, we shall not put the cart before the horse by asking what science is (or what the meaning of science is), or by asking what religion is (or what the meaning of religion is). These questions may be interesting from a linguistic or sociological angle, they need no precise answer when starting from such general concepts as proposition and theory. On our systematical approach the question is rather what distinguishes one body of propositions, or of uttered propositions, from another body of propositions, and what distinguishes one kind of theory from another kind of theory. Furthermore, we will have to clarify whether types of propositional entities semantically exclude each other by definition or whether, perhaps, the one type is to be subsumed under the other, also by definition. Altho we shall assume an instrumentalist attitude towards the use of terms like science and religion, it remains recommendable, of course, to stay as close as possible to the everyday meaning of such terms. That is, close enough but without mutilating our own body of thought.

Theorists and theoreticians have always referred to what philosophy, ideology, science 'and so on' --whatever that may mean-- are, or have in common, in many different ways. They have spoken of "sides of social life", "kinds of social activity" or "forms of behavior" (which would also include production and government). The same people who speak of "kinds of social activity" also call them "forms of intellectual activity"; this very much resembles the phrase intellectual undertakings. Other expressions employed to refer to science, religion, the arts 'and so on' are styles of thought or kinds of (cultural) symbol system. Since on our ontological construction the basic element of our own characterization of philosophy, ideology and so on is the proposition, it is the intellectual aspect, or the fact that we are dealing with thought, which should provide us with some unity in this muddle of designata. Accordingly, we take it that 'philosophy' or 'ideology' in our sense could never exist without thought but that they could exist without communication -- altho, perhaps, they could not. This is something else than claiming that philosophy, ideology, and also science, are social activities in which the presence of thought would be merely contingent. Moreover, even tho philosophy, ideology and science may be 'social activities' insofar as the act of thinking, which is language-dependent, is itself called "a social activity", the description is far too broad as it also encompasses all kinds of social activity, or sides of social life, which certainly do not belong to what we are dealing with here, such as organized sports, warfare and making love together.

The products of philosophy and science may be symbol systems, and in a loose sense they may be symbol systems themselves, yet also this typification is too broad, for languages are also symbol systems. And thought itself is then a symbol system or the production of such a system. This may confirm our position that there is a necessary relationship between the category to which philosophy, science, ideology and at least part of the arts belong and the activity of thinking, but there must be some quality in which these thought systems differ from other forms of thought. This essential feature is that philosophy, science, and so on, are modes of thought which are somehow governed by one or more principles, even if it is 'only' the principle to create something as beautiful as possible as may (but need not) be the case in literary undertakings -- and why only? As such they are modes of thought related to some theory or doctrine. The basics of such a theory or doctrine can be taught and learned. That is why we shall speak of "disciplinary thought". Philosophical, scientific, ideological and literary thought are disciplinary forms of thought in that they all relate to a particular field of study, or to a 'discipline' in the sense of a subject which can be taught and learned. Obviously it is not a good story or poem itself which can be learned but the art or principles of writing a good story or poem. What these principles are believed to be may differ from teacher to teacher, yet each teacher's thought itself is disciplinary, however much the choice of principles or theories may differ.

Nondisciplinary thought is at random or occasional. That does not mean that it must be false. But if it is true, and not purely observational (if, and insofar as, this is feasible), it is not yet knowledge but merely belief which happens to be true. (See 4.3.1.) Since disciplinary thought rests on at least one principle, it is not at random or occasional. Nevertheless, like nondisciplinary thought it may still be either true or false. Therefore it is nonsensical to define principle as general truth; at most a principle is a general proposition believed to be true, that is, a doxastic truth. It is better to conceive of a principle as something intended as a rule or code, not only of practical conduct but also of one's thinking in a particular field. As something which is meant to guide one's thought, a principle is then a fundamental assumption or law. (It must not be said that all thought in all its aspects is guided by principles, for this drains the concept of 'principle', and of 'discipline', of all meaning.)

Altho knowledge is a form of true disciplinary thought, even true disciplinary thought need not be knowledge -- it, too, may just happen to be true. Consider, for example, a religion (in the sense of a system of thought) whose fundamental tenet it is that everything written down in certain 'sacred scriptures' is true. Such a religion is a product or form of disciplinary thought founded upon a very lucid principle. It would be unlikely that literally all the propositions in those sacred scriptures would be false, but it would also be unlikely that a true proposition in one of those scriptures would be the result of scientific deliberation or philosophical reflection. Thus according to the religion in question people should not solely take false propositions as true, but also true ones (the only requirement being that the pronouncements appear in the chosen writings). It follows that the system of disciplinary thought concerned does proclaim things which are true. However, judging by the principles which lead to knowledge as distinct from nonepistemic belief, their truth is a mere by-product of the religion's doxastic fundamental tenet.

Disciplinary thought may be said to reflect or constitute a theory or doctrine. If there exists any difference in meaning between theory and doctrine, then theory is more often associated with knowledge, and doctrine with (nonepistemic) belief. For example, theory is sometimes defined as general or abstract principles of a body of science or as plausible or scientifically acceptable general principle or body of principles offered to explain phenomena, whereas doctrine has been defined as belief or set of beliefs which is taught. On the other hand, the main, general and abstract principles of an art or of a form of art are called "theory" as well, while a doctrine may be either a system of belief or of knowledge when defined as principle or whole of principles in a branch of knowledge or system of belief. In short: we shall use theory and doctrine as synonyms, the sole difference being, perhaps, that a doctrine may encompass several theories, and not the other way around. Hence, both a 'theory' and a 'doctrine' may be a system of nonepistemic belief or of knowledge, and --what is an entirely different matter-- both may be true or false, let alone relevant or irrelevant.

Strictly from the point of view of ontology the most important subdivision of disciplinary thought is that into factual, modal and normative disciplinary thought. This is a subdivision based on the triadic sphericity of reality. Disciplinary thought may also be subdivided on the basis of other factors tho, for example, according to the social function or esthetic qualities of a theory or body of theories. It is when a mixture of several of these factors is considered that we arrive at the departments of disciplinary thought which are generally acknowledged in everyday language, such as science and philosophy. In the following two sections we shall discuss four of such departments without claiming to cover all of them.