Editing David Deutsch (section)

=== Invariants ===
In a 2009 [[TED talk]], Deutsch expounded a criterion for scientific explanation, which is to formulate [[Invariant (physics)|invariants]]: "State an explanation [publicly, so that it can be dated and verified by others later] that remains invariant [in the face of apparent change, new information, or unexpected conditions]".<ref name="TED">{{Cite AV media |url=https://www.ted.com/talks/david_deutsch_a_new_way_to_explain_explanation |title=A new way to explain explanation |date=October 2009 |last=Deutsch |first=David |publisher=TED talk |access-date=16 September 2018 |archive-date=4 November 2018 |archive-url=https://web.archive.org/web/20181104012430/https://www.ted.com/talks/david_deutsch_a_new_way_to_explain_explanation |url-status=live }} Also available from [https://www.youtube.com/watch?v=folTvNDL08A YouTube] {{Webarchive|url=https://web.archive.org/web/20221108112725/https://www.youtube.com/watch?v=folTvNDL08A |date=8 November 2022 }}.</ref>
: "A bad explanation is easy to vary."<ref name=TED />{{rp| minute 11:22}}
: "The search for hard-to-vary explanations is the origin of all progress"<ref name=TED />{{rp| minute 15:05}}
: "That {{em|the truth consists of hard-to-vary assertions about reality}} is the most important fact about the physical world."<ref name=TED />{{rp| minute 16:15}}

Invariance as a fundamental aspect of a scientific account of reality has long been part of philosophy of science: for example, Friedel Weinert's book ''The Scientist as Philosopher'' (2004) noted the presence of the theme in many writings from around 1900 onward, such as works by [[Henri Poincaré]] (1902), [[Ernst Cassirer]] (1920), [[Max Born]] (1949 and 1953), [[Paul Dirac]] (1958), [[Olivier Costa de Beauregard]] (1966), [[Eugene Wigner]] (1967), [[Lawrence Sklar]] (1974), [[Michael Friedman (philosopher)|Michael Friedman]] (1983), [[John D. Norton]] (1992), [[Nicholas Maxwell]] (1993), [[Alan Cook (physicist)|Alan Cook]] (1994), [[Alistair Cameron Crombie]] (1994), [[Margaret Morrison (philosopher)|Margaret Morrison]] (1995), [[Richard Feynman]] (1997), [[Robert Nozick]] (2001), and [[Tim Maudlin]] (2002).<ref>{{Cite book |last=Weinert |first=Friedel |title=The Scientist as Philosopher: Philosophical Consequences of Great Scientific Discoveries |date=2004 |publisher=[[Springer-Verlag]] |isbn=3540205802 |location=Berlin; New York |pages=62–74 (72) |chapter=Invariance and reality |doi=10.1007/b138529 |oclc=53434974|url=https://cds.cern.ch/record/828852 }}</ref>