Explanatory power
Explanatory power is the ability of a hypothesis or theory to explain the subject matter effectively to which it pertains. Its opposite is explanatory impotence.
In the past, various criteria or measures for explanatory power have been proposed. In particular, one hypothesis, theory, or explanation can be said to have more explanatory power than another about the same subject matter
If more facts or observations are accounted for;
If it changes more “surprising facts” into “a matter of course” (following Peirce);
If more details of causal relations are provided, leading to a high accuracy and precision of the description;
If it offers greater predictive power (if it offers more details about what should be expected to be seen and not seen);
If it depends less on authorities and more on observations;
If it makes fewer assumptions;
If it is more falsifiable (more testable by observation or experiment, according to Popper).
If it can be used to compress encoded observations into fewer bits (Solomonoff’s theory of inductive inference)
Recently, David Deutsch proposed that theorists should seek explanations that are hard to vary. A theory or explanation is hard to vary if all details play a functional role, i.e., cannot be varied or removed without changing the predictions of the theory. Easy to vary (i.e., bad) explanations, in contrast, can be varied to be reconciled with new observations because they are barely connected to the details of the phenomenon of question.
The Explanatory Scope Test, in the context of evaluating scientific theories or explanations, refers to assessing how broadly a theory can explain a range of phenomena. A theory with a broad explanatory scope can account for many different observations, while a theory with narrow scope is limited to a smaller set of phenomena.
Key aspects of the Explanatory Scope Test:
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Range of Phenomena: A theory’s explanatory scope is determined by the number and variety of observations it can explain. A theory that explains diverse phenomena is considered to have a broader scope than one that only explains a limited set of events.
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Comparison with Alternatives:
When evaluating a theory, its explanatory scope is often compared to that of competing theories. A theory with a broader scope, that also explains the same phenomena as a rival theory, is generally preferred.
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Relationship to other virtues:
Explanatory scope is often considered alongside other factors when evaluating the quality of an explanation, such as its [predictive power], [empirical support], and [theoretical coherence]. A theory that is both broad in scope and empirically well-supported is highly valued.
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Not a definitive measure:
While explanatory scope is an important factor in evaluating theories, it is not the only one. A theory with a broad scope but weak empirical support may be less desirable than a theory with a narrow scope but strong empirical support.
In essence, the Explanatory Scope Test helps assess how comprehensively a theory explains the world around it, with broader scope often being a desirable characteristic.