entity--a bent stick in water--that one perceives and that appears to be
exactly where the genuinely straight stick is. But clearly it cannot be;
for the entity that exists exactly where the straight stick is is the stick
itself, an entity that is not bent. Thus, the question arises as to what
kind of a thing this bent-stick-in-water is and where it exists.
The responses to these questions have been innumerable, and nearly all of
them raise further difficulties. Some theorists have denied that what one
sees in such a case is an existent entity at all but have found it
difficult to explain why one seems to see such an entity. Still others have
suggested that the image seen in such a case is in one's mind and not
really in space. But then what is it for something to be in one's mind,
where in the mind is it, and why, if it is in the mind, does it appear to
be "out there," in space where the stick is? And above all, how does one
decide these questions? The various questions posed above only suggest the
vast network of difficulties, and in order to straighten out its tangles it
becomes indispensable to develop theories.
Methodology.
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In accordance with a proposal made above, epistemology, or the logic of
scientific discovery, -should be identified with the theory of scientific
method. The theory of method, in so far as it goes beyond the purely
logical analysis of the relations between scientific statements, is
concerned with the choice of methods—with decisions about the way in which
scientific statements are to be dealt with. These decisions will of course
depend in their turn upon the aim, which we choose from among a number of
possible aims.
Methodology or a scientific method is a collective term denoting the
various processes by the aid of which the sciences are built up. In a wide
sense, any mode of investigation by which scientific or other impartial and
systematic knowledge is acquired is called a scientific method.
What are the rules of scientific method, and why do we need them? Can
there be a theory of such rules, a methodology? The way in which one
answers these questions will largely depend upon one’s attitude to science.
The way in which one answers these questions will largely depend upon one's
attitude to science. Those who, like the positivists, see empirical science
as a system of statements, which satisfy certain logical criteria, such as
meaningfulness or verifiability, will give one-answer. A very different
answer will be given by those who tend to see the distinguishing
characteristic of empirical statements in their susceptibility to
revision—in the fact that they can be criticised,-and superseded by better
ones; and who regard it as their task to analyse the characteristic ability
of science to advance, and the characteristic manner in which a choice is
made, in crucial cases, between conflicting systems of theories.
Such methods, as it was mentioned above, are of two principal types—
technical and logical. A technical or technological method is a method of
manipulating the phenomena under investigation, measuring them with
precision, and determining the conditions under which they occur, so as to
be able to observe them in a favourable and fruitful manner. A logical
method is a method of reasoning about the phenomena investigated, a
method of drawing inferences from the conditions under which they occur, so
as to interpret them as accurately as possible. The term "scientific
method" in the first instance probably suggests to most minds the technical
methods of manipulation and measurement. These technical methods are very
numerous and they are different in the different sciences. Few men ever
master the technical methods of more than one science or one group of
closely connected sciences. An account of the most important technical
methods is usually given in connection with the several sciences. It would
be impossible, even if it were desirable, to give a useful survey of all,
or even of the most important, technical methods of science. It is
different with the logical methods of science. These methods of reasoning
from the available evidence are not really numerous, and are essentially
the same in all the sciences. It is both possible and desirable to survey
them in outline. Moreover, these logical methods of science are in a very
real sense the soul of the technical methods.
In pure science the technical methods are not regarded as an end in
themselves, but merely as a means to the discovery of the nature of the
phenomena under investigation. This is done by drawing conclusions from the
observations and experiments, which the technical methods render possible.
Sometimes the technical methods make it possible for the expert
investigator to observe and measure certain phenomena, which otherwise
could either not be observed and measured at all, or not so accurately.
Sometimes they enable him so to determine the conditions of their
occurrence that he can draw reliable conclusions about them, instead of
having to be content with unverified conjectures. The highly speculative,
mainly conjectural character of early science was no doubt due entirely to
the lack of suitable technical methods and scientific instruments. In a
sense; therefore, it may be said that the technical methods of science are
auxiliary to the logical methods, or methods of reasoning. And it is these
methods that are to be considered in the present article. The technical
methods of science, as ought to be clear from the preceding remarks, are of
first rate importance, 'and we have not the remotest desire to underrate
them; but it would be futile to attempt to survey them here.
Some Mental Activities Common to All Methods.
There are certain mental activities, which are so absolutely
indispensable to science that they are practically always employed in
scientific investigations, however much these may vary in other respects.
In a wide sense these mental activities might consequently be called
methods of science, and they are frequently so called. But this practice is
objectionable, because it leads to cross division and confusion. What is
common to all methods should not itself be called a method, for it only
encourages the effacing of important differences; and when there are many
such factors common to all the methods, or most of them, confusion is
inevitable. When the mental activities involved are more or less common to
the methods, these must be differentiated by reference to other, variable
factors—such as the different types of data from which the inferences are
drawn, and the different types of order sought or discovered in the
different kinds, of phenomena investigated— the two sets of differences
being, of course, intimately connected. The mental activities referred to
are the following: Observation (including experiment), analysis and
synthesis, imagination, supposition and idealisation, inference (inductive
and deductive), and comparison (including analogy). A few words must be
said about each of these; but no significance should be attached to the
order in which they are dealt with.
Observation and Experiment.
Observation is the act of apprehending things and events, their
attributes and their concrete relationships. From the point of view of
scientific interest two types of observation may be distinguished, namely:
(1) The bare observation of phenomena under conditions which are beyond the
control of the investigator, and (2) experiment, that is, the observation
of phenomena under conditions controlled by the investigator. What
distinguishes experiment from bare observation is control over what is
observed, not the use of scientific apparatus, nor the amount of trouble
taken. The mere use of telescopes or microscopes, etc., even the selection
of specially suitable times and places of observation, does not constitute
an experiment, if there is no control over the phenomenon observed. On the
other hand, where there is such control, there is experiment, even if next
to no apparatus be used, and the amount of trouble involved be negligible.
The making of experiments usually demands the employment of technical
methods, but the main interest centres in the observations made possible
thereby. The great advantage of experiment over bare observation is that it
renders possible a more reliable analysis of complex phenomena, and more
reliable inferences about their connections, by the variation of
circumstances, which it effects. Its importance is so great that people
commonly speak of "experimental method." The objection to this is that
experiment may be, and is, used in connection with various methods, which
are differentiated on other, and more legitimate, grounds. To speak of a
method of observation is even less permissible, seeing that no method can
be employed without it.
Analysis and Synthesis.
The phenomena of nature are very complex and, to all appearances, very
confused. The discovery of any kind of order in them is only rendered
possible by processes of analysis and synthesis. These are as essential to
all scientific investigation as is observation itself. The process of
analysis is helped by the comparison of two or more objects or events that
are similar in some respects and different in others. But while comparison
is a necessary instrument of analysis, analysis, in its turn, renders
