Theory-dependence of observation
The scientific method depends on observation, in defining the subject under investigation and in performing experiments.
Observation involves perception, and so is a cognitive process. That is, one does not make an observation passively, but is actively involved in distinguishing the thing being observed from surrounding sensory data. Observations, therefore, depend on some underlying understanding of the way in which the world functions, and that understanding may influence what is perceived, noticed, or deemed worthy of consideration. (See the Sapir-Whorf Hypothesis for an early version of this understanding of the impact of cultural artifacts on our perceptions of the world.)
It is reasonable, when someone claims to have made an observation, to ask them to justify their claim. Such a justification must itself make reference to the theory - the operational definitions and deductions from hypotheses - in which the observation is embedded. But this means, again, that observation by itself cannot be used to decide between competing theories. Empirical observation, during experimentation, is used to determine the acceptability of a hypothesis. Observation could only do this "neutrally" if the theory on which the observation depends and the theory being verified were independent of each other.
Kuhn denied that it is ever possible to isolate the theory being tested from influence by the theory in which the making of observations is grounded, arguing that observations always rely on a specific paradigm, and that it is not possible to evaluate competing paradigms independently. By "paradigm" he meant, essentially, a logically consistent "portrait" of the world, one that involves no logical contradictions. More than one such logically consistent construct can paint a usable likeness of the world, but it is pointless to pit them against each other, theory against theory. Neither is a standard by which the other can be judged. Instead, the question is which "portrait" is judged by some set of people to promise the most in terms of “puzzle solving”.
For Kuhn, the choice of paradigm was sustained by, but not ultimately determined by, logical processes. The individual's choice between paradigms involves setting two or more “portraits" against the world and deciding which likeness is most promising. In the case of a general acceptance of one paradigm or another, Kuhn believed that it represented the consensus of the community of scientists. Acceptance or rejection of some paradigm is, he argued, more a social than a logical process.
That observation is embedded in theory does not mean that observations are irrelevant to science. Scientific understanding derives from observation, but the acceptance of scientific statements is dependent on the related theoretical background or paradigm a well as on observation. Coherentism and scepticism offer alternatives to foundationalism for dealing with the difficulty of grounding scientific theories in something more than observations.
Indeterminacy of theory under empirical test
The Quine-Duhem thesis points out that any theory can be made compatible with any empirical observation by the addition of suitable ad hoc hypotheses. This is analogous to the way in which an infinite number of curves can be drawn through any set of data points on a graph.
This thesis was accepted by Karl Popper, leading him to reject naïve falsification in favour of 'survival of the fittest', or most falsifiable, of scientific theories. In Popper's view, any hypothesis that does not make testable predictions is simply not science. Such a hypothesis may be useful or valuable, but it cannot be said to be science. Confirmation holism, developed by W. V. Quine, states that empirical data is not sufficient to make a judgment between theories. A theory can always be made to fit with the empirical data available.
That empirical evidence does not serve to determine between alternat theories does not imply that all theories are of equal value. Rather than pretending to use a universally applicable methodological principle, the scientist is making a personal choice when she chooses some particular theory over another.
One result of this is that specialists in the philosophy of science stress the requirement that observations made for the purposes of science be restricted to intersubjective objects. That is, science is restricted to those areas where there is general agreement on the nature of the observations involved. It is comparatively easy for folk to agree on observations of physical phenomena, harder for them to agree on observations of socia or mental phenomena, and difficult in the extreme to reach agreement on matters of theology or ethics.
Scientific Method is often touted as determining which disciplines are scientific and which are not. Those which follow the scientific method might be considered sciences; those that do not are not. That is, method might be used as the criterion for demarcation between science and non-science.
If observation cannot act as a theory-independent foundation for the Source | Copyright