The “War Against Science”: Does theory change in science undermine scientific realism?
Prologue
I’m sure you’ve heard about this long controversy on global warming recently boosted by Trump administration. He is continuously accusing climate scientists and calling climate change a “hoax” (though he later retracted that statement).
“Don’t forget, it used to be called global warming, that wasn’t working, then it was called climate change, now it’s actually called extreme weather because with extreme weather you can’t miss,” -
Donald Trump quote in his meeting with Prince Charles on June 5th
It’s very interesting to see in the 21st century, the president of the greatest country in the world has such an apparent “War on Science”. Whether it’s a “hoax” or not is not my interest. The matter first came into my attention when he opened the discussion of “theory change in science” which was a classic debate in scientific history. It’s actually started sometime at the end of the nineteenth century and has been continued till mid-twentieth. This was one of the main arguments of antirealists, such as Tolstoy, that whether theory change in scientific history undermine scientific realism or not.
In this note, I’m going to take a more in-depth look at this argument.
The debate about scientific realism
Scientific Realism’s Epistemic Optimism
Even though there are several different definitions for Scientific Realism (SR), but as a general definition, it is an epistemic approach toward the essence of our finest theories in science, advocating belief in both observable and unobservable aspects of the world described by the sciences. According to SR, the epistemic status of a scientific theory deals with the degree of commitment to the theory based on the justification of inferred knowledge (observable or not).
However, if we look at the different definitions of scientific structure (such as Kuhnian’s definition of scientific structure), as well as referring to the history of scientific theories in the past millennia, apparently almost all scientific theories and models are doomed: despite from their epistemic success, they eventually being replaced by a better theory or considered strictly false. For sure, this results in numerous critiques of science as a whole.
The Debate over the “Bankruptcy of Science”
Combining the ephemeral nature of scientific theories with the SR’s view on the epistemic commitment to them, makes a paradoxical debate: how come realists can reasonably be optimistic about the truth of currently empirically successful theories?
Between 1889 to 1904, Ferdinand Brunetière and Leo Tolstoy initiated a historical debate [6] over the ephemerality of scientific theories in Paris, France:
Lastly, does not each year produce its new scientific discoveries, which after astonishing the boobies of the whole world and bringing fame and fortune to the inventors, are eventually admitted to be ridiculous mistakes even by those who promulgated them? -
“The Non-Acting” by Tolstoy
On the other hand, realists have tried to respond to the above argument by showing that there is a substantive continuity in every theory-change throughout the history of science, that guarantees the optimism on the current science.
What is Pessimistic Induction?
As described in the first section, realists defend their belief on the approximate truthfulness of current best scientific theories and models. Larry Laudan had been hypothesized the Pessimistic Induction (PI) in 1981 (also known as pessimistic meta-induction) which undermines such epistemic optimism via the historical facts discussed in the previous section. According to pessimistic induction, there is no reason to believe our currently successful theories are (approximately) true as historically past epistemically successful theories were found to be false.
There are several responses to the PI. For example, many realists argued that Laudan’s do not represent the most successful examples of the past epistemically successful theories at their time. Some others, mentioned that it’s not always the case that we completely refute all parts of an old theory, but instead, some parts carry over the new theories.
The “Disasterous Meta-Induction”
Hilary Whitehall Putnam, an American philosopher, crystallized PI in what he calls the “disastrous meta-induction of scientific theorizing” [5]. His argument has different versions that differ in details. In general, it begins by recalling that several scientific theories and models were epistemically successful in the past, but later on, most of them have been considered as strictly false. The inductive reasoning behind this argument is quite simple and Peter J. Lewis reconstructed [3] the argument as follows:
- Assume that the success of a theory is a reliable test for its truth.
- Most current scientific theories are successful.
- So most current scientific theories are true.
- Then most past scientific theories are false, since they differ from current theories in significant ways.
- Many of these false past theories were successful.
- So the success of a theory is not a reliable test for its truth.
Realists responded to this line of reasoning by arguing that it’s because of the present scientific theories that we can judge those past theories are false. Therefore, if we conclude that no present theory is true (based on the meta-induction), then there is no ground to believe the past theories were false. Thus the argument is self-undermining.
Mary Hess’s Principle of No Privilege
Mary Brenda Hesse, an English philosopher of science, has a similar pessimistic argument referred to as “principle of no privilege” (POLP) and it has very simple reasoning behind [1]: current theories are as false as the past ones.
“our own scientific theories are held to be as much subject to radical conceptual change as past theories are seen to be.” -
“Truth and the growth of scientific knowledge” by Mary Hesse
Realists argue that it’s not always the case that the past theories are incompatible with the new ones. It is possible to claim that past and present scientific ontologies are compatible, even during the theory change. Therefore, this line of reasoning is not complete.
Laudan’s “Historical Gambit”
Realists attempt to answer several other arguments, such as Laudan’s famous “historical gambit” [2]. An inductive format of his famous “6:1 ratio” problem is as follows:
“There has been a plethora of theories (ratio 6 to 1) which were successful and yet not truthlike. Therefore, it is highly probable that current theories will not be truthlike (despite their success).” -
“A confutation of convergent realism” by Larry Laudan [2]
Despite the fact that the above conclusion looks too strong to perceive as valid, Moti Mizrahi [4] mentioned a serious flaw of this argument by referring to the issue of how we judge success and referential failure of scientific theories.
Other defends of realism
In this note, I’ve summarized both SR’ and PI’ viewpoints about one of the most important questions throughout the history of science “Does theory-change in the history of science undermine scientific realism?”.
One of the key points for realism to defend historical induction (raised by the theory-change) is that current theories are more truth-like than past theories because they have had more predictive power than past ones. In other words, the empirical success of current theories is a result of their increasing truthlikeness and their ability to yield better prediction about the world than older ones.
Another strategy to refute different variations of the PI is the divide et impera strategy. This response suggests that there has been enough theoretical continuity in scientific theory-change to warrant that science is following a course that is likely to result in success.
Even nowadays, this is an active area of debate for philosophers. I personally believe that if the scientific community follow a healthy scientific process then the theory-change is an inevitable part of it as our observation of the world changes over time due to the technological advancements (having access to more advanced equipment, sensors and tools).
References
[1] Mary Hesse. Truth and the growth of scientific knowledge. PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association, 1976:261–280, 1976. ISSN 02708647. URL http://www.jstor.org/stable/192385.
[2] Larry Laudan. A confutation of convergent realism. Philosophy of Science, 48(1):19–49, 1981. ISSN 00318248, 1539767X. URL http://www.jstor.org/stable/187066.
[3] Peter J. Lewis. Why the pessimistic induction is a fallacy. Synthese, 129(3):371–380, Dec 2001. ISSN 1573–0964. doi: 10.1023/A:1013139410613. URL https://doi.org/10.1023/A:1013139410613.
[4] Moti Mizrahi. The pessimistic induction: a bad argument gone too far. Synthese, 190(15):3209–3226, Oct 2013. ISSN 1573–0964. doi: 10.1007/s11229–012–0138–3. URL https://doi.org/10.1007/s11229-012-0138-3.
[5] Hilary Putnam. Explanation and Reference, pages 199–221. Springer Netherlands, Dordrecht,1973. ISBN 978–94–010–2548–5. doi: 10.1007/978–94–010–2548–5_11. URL https://doi.org/10.1007/978-94-010-2548-5_11.
[6] L. Tolstoy and A. Maude. Essays and Letters /by Leo Tolstoy ; Translated by Aylmer Maude. The works of Leo Tolstoy. G. Richards, 1903. URL https://books.google.se/books?id=cbRHAQAAMAAJ.
