Theory Rejection theorem (Barseghyan-2015)
This is an answer to the question Mechanism of Theory Rejection that states "A theory becomes rejected only when other theories that are incompatible with the theory become accepted."
Initially, the theory rejection theorem was accepted as deducible from the conjunction of the first law for theories and Harder's zeroth law. After the replacement of Harder's zeroth law with the compatibility corollary, suggested by Fraser and Sarwar, it became accepted that the theory rejection theorem is a deductive consequence of the first law for theories and the compatibility corollary.2
|Community||Accepted From||Acceptance Indicators||Still Accepted||Accepted Until||Rejection Indicators|
|Scientonomy||1 January 2016||The theorem became de facto accepted by the community at that time together with the whole theory of scientific change.||Yes|
Theory Rejection theorem (Barseghyan-2015) is an attempt to answer the following question: How do theories become rejected? What is the mechanism of theory rejection?
See Mechanism of Theory Rejection for more details.
According to the theory rejection theorem, a theory becomes rejected only when other theories that are incompatible with the theory become accepted.
Implicit in the theorem is the idea that each theory is assessed on an "individual basis by its compatibility with the propositions of the newly accepted theory".1 If it turns out that a previously accepted theory is compatible with the newly accepted theory, it remain in the agent's mosaic.
Barseghyan notes that, although we normally expect a theory to be replaced by another theory in the same "field" of inquiry, this is not necessarily the case. For example, he writes, "HSC knows several cases where an accepted theory became rejected simply because it wasn’t compatible with new accepted theories of some other fields".1
Barseghyan summarizes the theory rejection theorem as such:
In short, when the axioms of a theory are replaced by another theory, some of the theorems may nevertheless manage to stay in the mosaic, provided that they are compatible with the newly accepted theory. This is essentially what the theory rejection theorem tells us. Thus, if someday our currently accepted general relativity gets replaced by some new theory, the theories that followed from general relativity, such as the theory of black holes, may nevertheless manage to remain in the mosaic. 1
The gist of this theory can be illustrated by the following examples.
The rejection of theology proper (the study of God, his being, his attributes, and his works) from the scientific mosaic is a historical illustration of the Theory Rejection theorem and how accepted theories in one field may become rejected due to theories in other fields. In essence, theological propositions were rejected, but were not replaced with more theological propositions. It is difficult to track the exact dynamics of theology's "exile," but it is possible that these propositions were rejected and replaced with the thesis of agnosticism, or that they were rejected due to the acceptance of evolutionary biology. The "exile," as Barseghyan terms it, could have also been a very gradual process, and that the rejection of theological propositions came about for different reasons in different mosaics. Despite the difficulties in tracking down the exact dynamics of the gradual rejection of theology from the scientific mosaic, Barseghyan summarizes the evidence as such: "what must be appreciated here is that a theory can be replaced in the mosaic by theories pertaining to other fields of inquiry".1
Another example of the theory rejection theorem, specifically explaining that theories may not only be rejected because of the acceptance of new theories in their respective theories, is the case of natural astrology presented in Barseghyan (2015).
The exile of astrology from the mosaic is yet another example. It is well known that astrology was once a respected scientific discipline and its theories were part of the mosaic. Of course, not all of the astrology was accepted; it was the so-called natural astrology – the theory of celestial influences on physical phenomena of the terrestrial region – that was part of the Aristotelian-medieval mosaic. ... Although, for now, we cannot reconstruct all the details or even the approximate decade when the exile of natural astrology took place, one thing is clear: when the once-accepted theory of natural astrology became rejected, it wasn’t replaced by another theory of natural astrology.1
Barseghyan considers the case of plenism, "the view that there can be no empty space (i.e. no space absolutely devoid of matter)", as a key historical illustration of the Theory Rejection theorem in Barseghyan (2015).
Within the system of the Aristotelian-medieval natural philosophy, plenism was one of many theorems. Yet, when the Aristotelian natural philosophy was replaced by that of Descartes, plenism remained in the mosaic, for it was a theorem in the Cartesian system too. To appreciate this we have to consider the Aristotelian-medieval law of violent motion, which states that an object moves only if the applied force is greater than the resistance of the medium. In that case, according to the law, the velocity will be proportional to the force and inversely proportional to resistance. Otherwise the object won’t move; its velocity will be zero ...
Taken as an axiom, this law has many interesting consequences. It follows from this law, that if there were no resistance the velocity of the object would be infinite. But this is absurd since nothing can move infinitely fast (for that would mean being at two places simultaneously). Therefore, there should always be some resistance, i.e. something that fills up the medium. Thus, we arrive at the conception of plenism ...
There weren’t many elements of the Aristotelian-medieval mosaic that maintained their state within the Cartesian mosaic. The conception of plenism was among the few that survived through the transition. In the Cartesian system, plenism followed directly from the assumption that extension is the attribute of matter and that no attribute can exist independently from the substance in which it inheres ...
In short, when the axioms of a theory are replaced by another theory, some of the theorems may nevertheless manage to stay in the mosaic, provided that they are compatible with the newly accepted theory. This is essentially what the theory rejection theorem tells us. Thus, if someday our currently accepted general relativity gets replaced by some new theory, the theories that followed from general relativity, such as the theory of black holes, may nevertheless manage to remain in the mosaic.1
Reason: Theory Rection Theorem deduction (2018)
By the first law for theories, an accepted theory remains accepted until it is replaced by other theories. By the compatibility corollary, the elements of the scientific mosaic are compatible with each other at any moment of time. It follows, therefore, that a theory can only become rejected when it is replaced by an incompatible theory or theories.1 2
Reason: 2015 Deduction of the Theory Rejection theorem
Barseghyan presented the initial deduction (2015) of the theorem:
By the first law for theories, we know that an accepted theory can become rejected only when it is replaced in the mosaic by some other theory. But the law of compatibility doesn’t specify under what conditions this replacement takes place. For that we have to refer to the zeroth law, which states that at any moment of time the elements of the mosaic are mutually compatible. Suppose that a new theory meets the requirements of the time and becomes accepted into the mosaic. Question: what happens to the other theories of the mosaic? While some of the accepted theories may preserve their position in the mosaic, other theories may be rejected. The fate of an old accepted theory depends on whether it is compatible with the newly accepted theory. If it is compatible with the new accepted theory, it remains in the mosaic; the acceptance of the new theory doesn’t affect that old theory in any way. This is normally the case when the new theory comes as an addition to the theories that are already in the mosaic. For instance, when the new theory happens to be the first accepted theory of its domain, i.e. when there is a new field of science that has never had any accepted theories before). Yet, if an old theory is incompatible with the new one, the old theory becomes rejected, for otherwise the mosaic would contain mutually incompatible elements, which is forbidden by the law of compatibility. Therefore, there is only one scenario when a theory can no longer remain in the mosaic, i.e. when other theories which are incompatible with that theory become accepted.1
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Questions About This Theory
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- Barseghyan, Hakob. (2015) The Laws of Scientific Change. Springer.
- Fraser, Patrick and Sarwar, Ameer. (2018) A Compatibility Law and the Classification of Theory Change. Scientonomy 2, 67-82. Retrieved from https://scientojournal.com/index.php/scientonomy/article/view/31278.