Whatever one's viewpoint, there are definitive distinctions that can be drawn between the natural sciences and the human sciences, between the empirical inductive method's assumptions and those of phenomenology and theory of interpretation.

Since the term 'science' is naturally connected with those disciplines which, since the Renaissance onwards, have made great advances in theoretical exactness, predictability and technical application, being known as the physical sciences, it is the methods and theory of these disciplines that is made most central in the forthcoming section.

In this age of science-based technology so advanced as to make everyone a layman in relation to the whole of scientific knowledge, one can hardly other than be impressed by the extent and accuracy of scientific explanations of reality. The number of factors to be known and controlled and the accuracy of calculations required in space travel would be amazing even to informed laymen of the previous century. In the face of this almost awe-inspiring success of scientific explanation, it is fitting to remember that the sciences today cannot explain everything. The most advanced sciences from the epistemological and methodological viewpoints are undoubtedly the physical sciences. Even in the natural realm, however, these sciences can only predict with accuracy under specific, limited conditions and usually over relatively very short time-scales. Prediction works best under experimental control conditions, yet these seldom prevail in real life. Much that occurs in space exploration is unpredictable, particularly the human factor and even more so the sociological and political factors involved here as in all human undertakings. That even the physical sciences are unable to predict with certainty in real life is witnessed daily by all who care to hear the weather report. Despite vast weather-monitoring systems including satellites, vastly increased data handling capacity and new global monitoring systems, a weather forecast can turn out to be about as wrong as the worst guess from the layman's point of view. Such inaccuracy and unpredictability in science apply with at least as much force in respect of the living kingdom. The conditions of birth, life and death are only most incompletely known. The exact time of birth or especially death is unpredictable. The number of births and deaths of any species can be predicted only with the roughest rule-of-thumb methods once the species in question is the size of a dog or smaller. One cannot predict with much accuracy - if any - the movements of bacteria, the behaviour of viruses, the rise and spread of epidemics, the movements of nature or the earth and so on.

The human sciences stand in a still weaker position as regards causal knowledge, for reasons to be discussed later in this part of the book. Future social events are highly impervious to scientific prediction, which is taken by some as an indicator of the level of advancement of a science. Economics is a widely known example of the inabilities of scientific explanation to forewarn and explain even the largest-scale movements of and economy. Small-scale trends in world trade and finance are about an unexplainable to the economist as are why the rate of homicide or suicide fluctuates. Predictions in social science and psychology are about as unreliable as guesses as to what will be invented in the future or what the fashions are likely to be in clothes, music or lifestyle within the coming decade.

With this in mind one may approach the theory of science with a rather more sceptical attitude than otherwise might be the case. A sceptical attitude is supposed to be the mainstay of science itself, meaning an .open, inquiring but highly-cautious frame of mind. Scepticism can be extreme or moderate - and often too mild - yet a moderate skepticism which is neither negative nor over-enthusiastic is what most historically-influential philosophers and scientists advocate.

It has been held that "conceptions are determined by life, not life by conceptions". This summarises quite succinctly the attitude of empirical scepticism. It should be remembered, however, that - as a scientist -life is approached through conceptions and - as theory of understanding explains - this is unavoidable. In this respect then, life is determined by conceptions. Which conceptions one holds will colour one's view. The value of the reminder that life is primary to conceptions, however, surely lies in the experience that one cannot impose any pet theory on reality, somehow due to the fact that reality resists all wishful thinking. It is so as to strike a balance between positive and negative attitudes, between extreme scepticism of the cynical sort and uncritical acceptance of any idea that - at least for scientific purposes - a moderate form of scepticism as part of the program of scientific training is usually advised As the theory of science is part of the philosophy of science, the traditional philosophical norm of 'reservation of judgement until the grounds are compelling' fits well with the program of scientific explanation, as well as giving a useful guide to the study of scientific claims altogether, as is the purpose of the philosophy of science.

What is Science?

Philosophical hermeneutics deals with the theory of understanding in general, as has been discussed in the proceeding. All human activities involve understanding at some level or to some extent. Those activities consisting in the pursuit of generalised knowledge is widely termed as 'science'. 'Science' is a term with widespread prestige and is one that many thus choose to use to refer to their own work. As such the term has come to have a variety of meanings, from the highly precise to the very vague. In the original, historical sense 'science' refers to that systematised knowledge of experientially-proven generalisations about physical nature, which shall hereafter be termed 'natural science'. Natural science regards nature only as physical and determinate, that is - as objectively- and independently-existing matter in process. Subjective phenomena (i.e. what goes on in the mind, thoughts or feelings etc.) are systematically excluded from its field of study - until or unless they can be shown to have objective existence as measurable, physical phenomena. Further, most theoreticians in the natural sciences usually reserve the term 'scientific explanation' for explanation by reference to general causes (causal explanation).

Nowadays the term science is used very broadly to include all manner of academically-instituted fields of interest. Subjects traditionally regarded as 'arts' (i.e. history, the study of literature and language etc.) are now almost always referred to as sciences. Similarly, subjects once commonly thought of as belonging outside science such as economics, social theory, pedagogy are included under the administration of the 'social sciences'. It has been common to regard the social sciences as in a borderland between the realms of 'pure science' and of applied political and moral activity. Even theology and philosophy have tended to become classified as sciences - or as employing scientific criteria and methods. Under these circumstances there tends to be much confusion as to the test of being 'scientific'. Therefore, central criteria and methods that variously apply in different sciences are discussed in the following.


Scientific Generalisation

Scientific generalisation proper constitutes one form of understanding of reality, being directed towards observable or sensory reality and thus forming a system of empirical generalisations and theories about physical processes. Strict or rigorously-exact scientific generalisation occurs only where physical processes are studied Where psychic and social processes are concerned, scientific generalisations are also widely held as an ideal in the sciences concerned, yet the exactitude and generality achievable is much less than in the former case, for reasons to be discussed later here.

The nature of systematic and logical scientific method is to find the connecting links between 'particulars', or isolated and fragmentary facts, so as to be able to arrive at 'general statements' (or empirical principles) - and, these being founded, continually to test them by bringing isolated facts which contain these 'common factors' under the general principles to see whether or not it confirms in other respects. Scientific method attempts to condense facts by extracting from a mass of them the attributes they have in common, which shows their position in some specific logical system of scientific theory. This 'system' is a conception of the mind to help explain the world around us with a view to employing, controlling or predicting material circumstances.

The starting point of scientific method is to observe physical 'reality' (i.e. facts of the world around us) and then produce conceptions of how these facts are inter-related and mutually-dependent. Scientific method can be built only upon observation (experience of facts), not vice-versa. This is obvious in itself when we consider that we learn to do everything we do before we conceive of our way - or method - of doing it, or why we do it (in a more special sense).

Scientific method forbids us to perceive only what we 'prefer' to find instead of what is generally observable. We can build fantasy conceptions - for one reason or the other - but these have no scientific value. Fantasy conceptions can not change the facts of the material world though they can affect the individual psychic life and sometimes also society. (The 'fantasies' of Nazi 'scientific theorists' about purity of the Aryan race provide a striking case). The more general principles which we arrive at by scientific method are an attempt to explain what is the case, whether or not we know why it is so.

System

The conception of 'system' is important both to logic and the sciences. 'System' is an 'organised, whole in which each element or part is mutually dependent upon each other element and which, when seen as a whole, is an orderly plan'.

All science begins from the postulate that what we can apprehend is in some way explainable to the mind. The way science attempts to explain the universe is by showing it to be a system, which is made up of yet more and more smaller and dependent systems - and the task of science is to understand more fully about each of these 'minor' systems until they can all be integrated, eventually into the ultimate system of unity. Without this 'postulate' science would lack any overall theoretical aim and we should have no way of extracting those principles of yet greater and greater generality, which themselves constitute system. Otherwise our minds would each have to hold every single particular instance of everything.


Nomothetic and Ideographic Science

Though system is essential to all scientific studies, scientific generalisation is not always so. To say that a science tries to establish general laws or principles under which individual instances can be ordered is to say that a science is 'nomothetic' (Gr. nomos = law). While it is true that the physical sciences are invariably nomothetic, this is not so of a number of disciplines called 'scientific' with good reason. A large number of historical or social studies are sciences in most other respects than this. The contrary tern 'ideographic' is used of the approach which attempts to give a detailed account of many unique instances and their inter-relationships without thereby aiming at establishing generalities about their subject matter. Such disciplines include various approaches in history (including the history of languages, literatures etc.), the study of social customs in social anthropology or ethnology and case-studies in the psychological and allied sciences.
Science as determined by method

Some philosophers of science have put forward a doctrine that there is one method which is scientific and which is shared by all disciplines of the sort mentioned above.. this method is referred to as hypothetical-deductive method. However, far from all philosophers of science agree.

Philosophers concerned with the physical sciences, especially atomic physics, tend to hold that what is called 'the' hypothetical-deductive method is just a loose general account of a variety of methods which, in actual practice, often bear little or no resemblance to one another and thus often fail to fit the hypothetical-deductive model. Not even in the natural science is hypothetical-deductive method a valid model that applies generally, according to some physicists, biologists etc., beyond the mere facts that both observation and theory are always necessarily present.

Another group of thinkers, including many of the most influential philosophers of the Continental European tradition, hold that hypothetical-deductive method may give a generally-valid account of the main procedures of certain sciences - especially the physical sciences - but that it is in principle quite inapplicable to those sciences they term 'the human sciences' or 'the historical sciences'. (The term 'human-historical sciences' nowadays covers largely what the old term 'arts' did. The term 'social sciences' is often used for much the same area of disciplines). Thinkers of this latter persuasion generally hold the hypothetico-deductive method only to be one specialised form of investigation. This method, they hold, presumes the field of inquiry and the purposes of the natural sciences, which differ radically in principle as well as in practice from those of the non-natural or 'human-historical' sciences for which meaningful behaviour is included in the field of study, or also the motives, aims and consequences of meaningful human actions). Thus, sciences concerned with the understanding of meaningful behaviour (as can also be expressed in texts or other symbolic forms) do not in this view employ the hypothetical-deductive method but use other approaches and methods, such as those of phenomenology, case analysis, ideographic description, functional analysis, systematic interpretation, comparative analysis etc.

Distinction between the natural and the human sciences

Important differences between the main types of science cannot be made only by one distinction. Even at a high level of generality, essential differences can be described by a series of pairs of concepts such as inductive or deductive (axiomatic) sciences, physical or historical, explanatory or interpretative, nomothetic or ideographic, pure or applied and so forth. The various branches of science bear resemblances to one another much as do the individual members of any family, and they differ much as individual family members can do. Two main families or branches generally recognised in practice (i.e. in institutional organisation and administration), which include groupings of disciplines according to their differing subject matter or fields of interest (with some 'crossover' disciplines), as the following illustrates very generally;-

Note: Neither mathematics, theology nor philosophy are included in the above as their status as sciences are controversial.