|
Author
|
Topic: Replacing a theory that is no longer sufficient
|
Roland F. Hirsch
Member
Member # 8
|
posted 18. October 2002 15:19
Those who support the Darwinian theories of evolution often respond to criticisms by asking what the critic is offering as a replacement. Yet science does not require that a replacement already be available when a theory proves insufficient to explain the experimental evidence. Indeed, as Freeman Dyson pointed out in Imagined Worlds (1997), "The effect of a tool-driven revolution is to discover new things that have to be explained." The major new tools for studying living organisms, such as for gene sequencing and cellular and chemical imaging, are providing much new information that needs a new kind of explanation.
The situation of the Darwinian theories of evolution vis-a-vis new experimental evidence is not unique in science. A good contemporary analogy may be with the field of superconductivity, though this field is perhaps rather narrower than biological evolution. The early discoveries of superconductivity were made without a theory to guide them. Then the BCS theory was developed (for which Bardeen, Cooper and Schrieffer received the Nobel Physics prize some years later, in 1972). Notice especially the phrase "a complete theoretical explanation of the phenomenon" in the first paragraph of the Nobel press release for them: (the complete text can be found at
http://www.nobel.se/physics/laureates/index.html )
"The phenomenon of superconductivity was discovered by the Dutch physicist Kamerling Onnes already in 1911. Already his first measurements indicated that one had found a fundamentally new state of matter. The term superconductivity refers to the complete disappearance of the electrical resistance. Many remarkable properties were discovered in the following decades. However, the central problem, the question about the underlying mechanism for superconductivity, remained a mystery up to the late 50:s. The difference in energy between the superconducting and the normal state in a metal is extremely small in comparison with all typical energies in a metal and therefore many different mechanisms might a priori be possible. A significant step forward was taken around 1950 when it was found theoretically and experimentally that the mechanism for superconductivity had to do with the coupling of electrons to the vibrations of the crystal lattice. Starting from this mechanism, Bardeen, Cooper and Schrieffer developed in 1957 a theory of superconductivity, which gave a complete theoretical explanation of the phenomenon."
Then in the 1980s new substances were discovered to be superconductors at much higher temperatures than the ones previously identified and explained by BCS (by much higher temperatures we are talking going from perhaps 30 K to above 80 K, the temperature of liquid nitrogen; this was very important because liquid nitrogen is very cheap, but the liquid helium used for the prior superconductors is very expensive). Bednorz and Müller received the Nobel Prize for Physics in 1987 for their contributions.
That these materials were superconductors at all was puzzling as they were unrelated in their composition to the known superconductors (they were oxides of a range of mixtures of metals, rather than purified alloys of a limited number of metals). At the moment there are many ("hundreds" one expert told me a couple of years ago) competing theories of superconductivity being developed and discussed to cover the new materials, but none is yet successful. Thus BCS explains a limited, now quite limited, range of superconductors, but nothing explains the larger range of superconductors.
Here are some excerpts from the citation for Bednorz and Müller in 1987:
"Bednorz' and Müller's new approach was to abandon the "conventional" semiconducting alloys, for instance of niobium-germanium or niobium-tin type, and to direct their search among metal oxides. It was known that some of these oxides may conduct electricity, but their conductivity is normally very limited.
"At first sight, therefore, it seems astonishing that such materials can ever pass to a superconducting state when cooled. Yet it was with various oxide materials (which in addition to oxygen contain copper or nickel and some of the rare earth elements) that Bednorz and Müller had worked since 1983."
...
"The details of how superconductivity arises in the new materials are still unknown. Intensive work is being carried out using the full arsenal of measuring methods within solid-state physics to uncover the essential mechanisms behind this phenomenon. One main question is whether the descriptions of superconductivity employed so far (i.e. the Bardeen-Cooper-Schrieffer theory) are sufficient, or whether new concepts will be needed. Perhaps it will be necessary to reconsider certain aspects of the motion and interaction of electrons in solid substances."
It is noteworthy that one can replace the phrases dealing with superconductivity and the tools of physics in this last paragraph with ones for evolution and the life sciences, and come up with a good statement of the problematic situation that the Darwinian theories of evolution are in at the present time.
[ 18. October 2002, 15:50: Message edited by: Roland F. Hirsch ]
IP: Logged
|
|
warren_bergerson
Member
Member # 262
|
posted 20. October 2002 08:59
Roland,
Quote: Those who support the Darwinian theories of evolution often respond to criticisms by asking what the critic is offering as a replacement. Yet science does not require that a replacement already be available when a theory proves insufficient to explain the experimental evidence. Indeed, as Freeman Dyson pointed out in Imagined Worlds (1997), "The effect of a tool-driven revolution is to discover new things that have to be explained." The major new tools for studying living organisms, such as for gene sequencing and cellular and chemical imaging, are providing much new information that needs a new kind of explanation.
As you properly state, ‘science’ does not require that a replacement be available when a theory proves insufficient. This is also true when a theory proves inadequate, incomplete, and/or inconsistent. You are also correct in observing that new discoveries suggest "new things that have to be explained". It is also true new discoveries can often invalidate evidence/arguments that was originally interpreted as supporting a theory.
The issue with respect to Darwinian theories of evolution is not, however, completely an issue of what science requires. The issue with respect to Darwinian theories is in part the failure and unwillingness of evolutionary biology to develop, accept and utilize objective, verifiable, quantifiable performance measures.
Consider the following potentially quantifiable performance measures:
1) Power: The complexity of adaptive solution that can be produced under specified conditions.
2) Speed- The time required to generate a specific adaptive solution.
3) Efficiency- The cost in lost lives to produce a specific adaptive solution.
It seems obvious that if theory or model of evolutionary change is to be sufficient or adequate, there must exist generally accepted measures of power, speed, and efficiency and the proposed theory or model must explain/simulate the power, speed, and efficiency of known evolutionary changes.
As you nicely document, science can recognize the need to reconsider or reformulate a theory even if a replacement theory is not available. To reach that point, however, the science must accept/recognize/utilize objective verifiable techniques for evaluating performance. The issue in evolutionary biology appears to be the failure to develop/accept quantifiable performance measures. In the absence of such generally accepted performance measures, there appears to be no need/willingness to recognize insufficiency.
IP: Logged
|
|
|
Printer-friendly view of this topic