This paper examines the successes and shortcomings of three mainstream philosophical theories on scientific progress, and then systematically sorts out the interpretations of three generations of historians of science on the nature of the scientific revolution in the 17th century based on the close relationship between the problem of scientific progress and the question of the origin of modern science. Based on Flores Cohen's kinematic explanation of the scientific revolution in the 17th century, and with reference to Quine's analysis of the static structure of scientific knowledge, the dynamic model of scientific progress is proposed, that is, scientific progress is a dynamic adjustment process between beliefs, theories and experiences from disjointed or contradictory to interrelated and mutually adaptable. Furthermore, this dynamic model is compared with Kuhn's paradigm theory and Stravens's knowledge machine theory, showing that this model can not only cover these two theories, but also explain the scientific progress and revolution that these two theories cannot explain.
The model of scientific progress has always been a hot topic in the philosophy of science, and its core is to answer: why has modern science continued to progress since its inception? So far, there are three mainstream theories to answer this question, namely Popper's falsificationism, Kuhn's paradigm theory, and Michael Strevens's knowledge machine theory. However, these three theories have certain limitations in terms of self-consistency and explanatory power.
In this article, I argue that in order to understand the pattern of scientific progress, we must first understand the nature of the scientific revolution in the 17th century, that is, how modern science was born in Western Europe in the 17th century. The scientific revolution of the 17th century has been studied in the field of science history for three generations, and the representative results include Corvallet's "mathematicalization" of nature, Westerford's "interaction of two currents" and Floris Cohen's "fusion of three ways of knowing". The goal of this paper is to provide a more explanatory dynamic model for scientific progress and scientific revolution by rationally absorbing the theories of three philosophers of science and three generations of historians of science. The meaning of dynamics is that the model aims to reveal the internal drivers and adaptation mechanisms of scientific progress.
Section 1 will reflect on each of the three mainstream philosophical theories of science and analyze their successes and shortcomings. For example, the Michelson-Morey experiment did not falsify the ether hypothesis; The revolution in molecular biology has also not occurred in the Kuhnian sense of anomalies, crises, and paradigm shifts. Stravens's theory of the knowledge machine does outperform falsification theory and paradigm theory by a large margin in terms of explanatory power, but it excludes the process of scientific discovery entirely.
Section 2 turns to the scientific revolution of three generations of historians of science, and discusses the significance of the progress of historiography theory for the philosophy of science. In fact, Kuhn's paradigm theory owes much to Kovalley's chronicle program. In the 70s of the 20th century, Westfort inherited and developed Kovalet's program of chronicle, trying to interpret the birth of modern science with the two main lines of thought of Pythagorean-Platonism and mechanistic-particulate theory. In the 21st century, Floris Cohen proposed a more comprehensive explanation for the scientific revolution of the 17th century: modern science is a gradual fusion of three different ways of knowing the world, namely, mathematical ways of knowing, philosophical ways of knowing, and experimental ways of knowing.
Section 3 is based on recent advances in historiographical theory and with reference to W. Quine. V. O. Quine's analysis of the overall structure of scientific knowledge proposes a dynamic model of scientific progress, that is, scientific progress is a dynamic adjustment process between beliefs, theories and experiences from mutual disconnection to mutual coordination, and explains historical scientific progress and scientific revolution according to this model. Quine analyzes the static structure of contemporary scientific knowledge, Flores Cohen describes the kinematic trajectory of the 17th-century scientific revolution, and this article explores the dynamic mechanisms of major scientific advances.
The final section compares the connections and differences between the proposed dynamic model and the existing philosophical theories of science, showing that this model can not only cover Kuhn's paradigm and Stravings's knowledge machine, but also explain the scientific progress and revolution that these two theories cannot explain. In particular, a distinction is made between belief and theory itself. Belief is the underlying concept of scientists at the individual level, while theory is the content of knowledge that can be tested and shared by the scientific community. This distinction not only avoids the pitfalls of relativism, but also allows scientific discovery to be seen as an equally important part of progress as scientific testing.
3 theories of philosophy of science
Among the three philosophical theories of science, namely Popper's falsificationism, Kuhn's paradigm theory, and Stravings's knowledge machine theory, the first two are very familiar to the domestic philosophical circles of science, so they are only briefly analyzed. According to Popper's falsificationism, the basic pattern of scientific progress is a cycle between conjecture and refutation: after a theoretical proposition made through conjecture is convictively falsified, people are forced to put forward new conjectures and accept new refutations, and scientific theories are progressive.
The difficulty with falsificationism is that falsification is not easier than verification. Mr. Hong Qian once pointed out: "In the certainty of scientific propositions, verifiability and falsifiability can only be regarded as special cases. "The main reason for this situation is that experiments do not test a single hypothesis, but a combination of hypotheses. A. Ayer, a British philosopher. J. Ayer makes this very clear: a statement has cognitive significance, and observational propositions can be deduced if and only if this statement is combined with other auxiliary hypotheses, and these observable propositions cannot be deduced from auxiliary hypotheses alone. It is expressed by the following formula
where Oi is an observational proposition, A is an auxiliary hypothesis, and H is the hypothesis to be tested. This means that conclusive trials are almost non-existent.
There are many such examples in the history of science. In the mid-19th century, there were two opposing theories about whether the aether of light was dragged by a medium. Fresnel asserted that the aether of light is partially dragged by a medium (flowing water), from which he derives the formula for the speed of light in flowing water. In 1859, the results of Fiso's experiments agreed well with this formula, seemingly falsifying the hypothesis that the ether is not dragged by a medium (flowing water or the earth). It is now known that this is not a judgmental experiment at all, because the auxiliary hypothesis of the existence of the quiescent aether is wrong.
Another situation is that when observations conflict with theoretical hypotheses, one can invent auxiliary hypotheses (including ad hoc hypotheses) to rescue existing theories. For example, the results of the Michelson-Morey experiment negate the second-order effect of aether drift, but Lorentz saves the existence of aether through the auxiliary hypothesis of "Lorentz contraction".
There is also the case where when experimental results do not correspond to existing theories, given the great success of existing theories, people simply ignore them. For example, in 1859, Le Verrier discovered that Mercury's perihelion was precession at 43 arc seconds per centennial, which seemed to falsify Newton's theory of gravity, but the vast majority of scientists "dried" this result there. This leads us to Kuhn's theory that only serious or massive anomalies cause a crisis.
Kuhn's so-called "structure of the scientific revolution" is the basic pattern of the evolution and replacement of scientific theories: conventional science→ anomalies and crises→ scientific revolution → conventional science. According to this model, conventional science is a paradigm-guided puzzle-solving activity; The development of conventional science leads to anomalies, and serious anomalies lead to crises; A new paradigm is born in a crisis, and the scientific revolution is a shift between the old and the new.
The limitations of paradigm theory mainly focus on three points: the problem of the mandatory nature of the paradigm, the problem of the incommensurability of the paradigm, and the problem of insufficient explanatory power of the paradigm theory.
1) The mandatory problem of the paradigm. Kuhn's use of paradigms to define scientific communities, thereby achieving a social reduction of scientific thought, puts the theory in danger of slipping into the quagmire of relativism. The real scientific community never believes in a single paradigm. An expert in gravitational theory, while accepting general relativity, will also accept Newton's theory of universal gravitation, in addition, will also pay attention to the development of quantum gravitational theory. In other words, the dominant paradigm, while influential, is not coercive.
2) The problem of the incommensurability of paradigms. There has been a lot of talk in the academic community, but I will only emphasize Donald Davidson's view that Kuhn's paradigm theory is inconsistent. Kuhn's theory denies on the one hand empirical facts independent of paradigms, and on the other hand admits "anomalies", which implies the existence of a neutral world that has nothing to do with any paradigm.
3) The problem of insufficient explanatory power of paradigm theory. To quote Ian Hacking directly: "First of all, it is important to note that Kuhn is not talking about the scientific revolution of the 17th century. It is a far cry from the revolution in which Kuhn assumed its structure. Indeed, shortly before the publication of Structure, Kuhn had proposed the existence of a "second scientific revolution" that took place in the early 19th century, in which all new fields were mathematized. Thermal, optical, electrical, and magnetic sciences have all acquired their own paradigms, and previously chaotic phenomena are understood. This scientific revolution went hand in hand with what we call the Industrial Revolution and indisputably became the starting point of the modern techno-scientific world in which we find ourselves today. However, like the first scientific revolution, this one did not show the 'structure' of the scientific revolution as described in the Structure. ”
In fact, Kuhn's paradigm theory does not explain the evolutionary revolution, the genetics revolution, the molecular biology revolution, the special relativity revolution, the general relativity revolution, and the rise of hot big bang cosmology, because none of these revolutions came from a conflict between established theory and experience. The only new paradigm that really emerged from "anomalies and crises" was Lavoisier's redox theory and quantum mechanics of the 20th century. Still, the value of Kuhn's theory should not be underestimated. First, Kuhn's theory explains at least part of the scientific revolution; Second, Kuhn revealed the significance of the development of conventional science, that is, the development of conventional science will inevitably lead to a scientific revolution; Third, Kuhn emphasized the important influence of aesthetic and metaphysical factors in scientific progress.
The relativist tendencies of Kuhn's theory are overcome in Stravings's theory of the knowledge machine. Stravens returned to the tradition of empiricism and developed a more refined empiricism. Like the logical empiricist, Stravins distinguishes between the process of discovery, which is a matter for the individual scientist, and the process of confirmation, which is a matter for the scientific community. The scientific community follows an "iron rule" that a theory, no matter how beautiful or profound, must and only obey empirical evidence. Scientific theories pursue a "shallow explanation" of the world, not a "deep explanation" as traditional metaphysics requires. Newton's famous quote "hypotheses non fingo" is the best example of this: gravity does exist, and that is enough; As for what exactly it is, no hypothesis.
With regard to the iron law, Stravings proposed two insightful concepts, namely the "Tychonic principle" and the "Baconian convergence". Tycho's principle states that "the mysteries of the universe reside in subtle structures, in almost indistinguishable details, in patterns that can only be detected by the most sensitive, ingenious, and expensive instruments." Stravings named it the Tycho Principle because Tycho was an extremely keen observer, and his precise observations led to the birth of a new astronomy, Kepler astronomy. Kepler's own statement is proof of this: "Thanks to God's gift, we have Tycho, the most diligent observer, whose observations showed that Ptolemy's model of Mars had an error of 8 arc minutes." We believe that this is a mistake brought about by the hypothesis, so let's dedicate ourselves to this in order to finally discover the true form of celestial motion. …… These 8 arc minutes are not to be overlooked, and they will lead us on the path of revolutionizing astronomy as a whole. ”
Bacon convergence means that "as long as we are guided by the explanatory power of theories, empirical tests will eventually sift out the truth from competing theories." For example, in the second half of the 16th century, there were three different theories of planetary astronomy, namely the Ptolemaic system, the Tycho system, and the Copernican system. By the end of the century, European astronomers had generally opted for the Copernican theory, as Tycho's observations of supernovae and comets (Figures 1 and 2) had destroyed belief in the immutability of the celestial realm and the crystal celestial sphere.
Fig.1 Tycho's map of Cassiopeia, showing the position of Supernova I in 1572
Fig.2 Tycho's observations of the comet of 1577 show that the comet came from much farther away than the moon
The knowledge machine theory does not pursue a complete explanation of the scientific revolution, and its main flaw is that it only considers the confirmation process, but not the discovery process. Without considering the discovery process, the significance of aesthetics, metaphysics, and deep explanations in scientific progress is naturally not reflected. The significance of aesthetic factors in scientific discovery is mainly reflected in the pursuit of simplicity and self-consistency of theories. In 1956, when Paul Dirac visited Moscow University, he wrote on a blackboard: "A physical law must possess mathematical beauty." Many of the major advances in the history of science have come from the pursuit of formal beauty. For example, Copernicus's main motivation for the heliocentric theory was that Ptolemy's model of eccentric wheels and parasites did not conform to Plato's perfect circle hypothesis. Einstein's creation of the special theory of relativity first came from his belief that Maxwell-Lorentz's electrodynamics should be true in all inertial frames. Dirac's relativistic quantum mechanics can be described as a stroke of genius that reconciles quantum mechanics and special relativity.
The significance of metaphysical factors in scientific progress is mainly reflected in the pursuit of deep explanations, that is, the pursuit of the reality and intelligibility of theoretical entities. The effect of this pursuit can only be seen from the long-term development of science. Let's start with Newton's "I don't make up hypotheses". Gravitational force is a force acting at a distance, and from a philosophical point of view, it is a mysterious, unacceptable magic. After the publication of Newton's book, Leibniz was "shocked" by Newton's failure to explain the reason for gravity. In his view, the cause was the "aethereal vortex." In 1864, Maxwell, after establishing the field theory of electromagnetism, also speculated that gravity should be reduced to the action of the etheric medium like electromagnetism (Figure 3). Eventually, Einstein succeeded in transforming Newton's theory of gravity into a field theory by creating the general theory of relativity. From the publication of Principia in 1687 to the creation of the general theory of relativity in 1915, scientists have not given up on the in-depth explanation of the nature of gravity for more than three centuries.
Fig.3 Maxwell's model of the ether
Three Generations of Historiography Theory
The analysis in Section 1 shows that the existing theories of scientific progress all have the problem of insufficient explanatory power due to their respective limitations. The author believes that in order to fully explain scientific progress, it is necessary to deeply understand the nature of the scientific revolution in the 17th century. For this reason, the author turns to the historiography of the Scientific Revolution. In the history of science, the term "scientific revolution" refers specifically to the scientific revolution of the seventeenth century, and this section will follow this convention.
Pioneering research into the scientific revolution owes Kovalé to it. Through his study of Galileo, Corvare proposed that the premise of the scientific revolution was a change in worldview, that is, the replacement of Aristotle's physical space with Euclid's mathematical space. He summed up this shift as "the mathematization of nature": "The two characteristics [of the scientific revolution] are: (1) the disintegration of the cosmos in order and the disappearance of all considerations based on this concept; and (2) the geometry of space, i.e., the substitution of isotropic and abstract Euclidean geometric spaces for the concrete world-space concepts of pre-Galilean physics. These two characteristics can be boiled down to the mathematization of nature (geometry) and the mathematization of science (geometry). ”
Later, Corvallet realized that mathematical Platonism alone was not enough to explain the rise of modern physics. Through his study of Newton, he went on to argue that the scientific revolution was the result of the combined action of Platonism and the philosophy of microparticles: "In Newton, the book of nature was written in the language of particles, as in the case of Boyle; However, the syntax that binds them together and gives meaning to the whole book is purely mathematical, as is the case with Galileo and Descartes. ”
Kovalé's arguments about the Scientific Revolution inspired the understanding of the scientific revolution by the second generation of historians of science. In The Construction of Modern Science: Mechanism and Mechanics, Westford argues that the scientific revolution was the result of the interaction of two major currents: Plato-Pythagorean and mechanistic philosophy. In the preface to the book, he writes: "Two major themes dominated the scientific revolution of the 17th century—Plato-Pythagoreanism and mechanistic philosophy. Plato-Pythagoreanism looked at nature in geometric terms, convinced that the universe was built according to the principles of mathematical order; Mechanistic philosophy, on the other hand, envisions nature as a giant machine and attempts to explain the mechanisms behind it. …… These two traditions are not always compatible. The Pythagorean tradition deals with phenomena through order, content with discovering precise mathematical descriptions and understanding this description as an expression of the ultimate structure of the universe. Mechanistic philosophy, on the other hand, is concerned with the causal explanation of individual phenomena. …… Mechanistic philosophers in general seek to remove all obscure traces from natural philosophy, showing that natural phenomena are caused by invisible mechanisms that are exactly similar to those known in everyday life. These two ideological movements pursue different goals and often conflict with each other. …… Explanations of mechanical causality are often the opposite of the path of precise description, and the full realization of the scientific revolution requires the resolution of the tension between these two dominant tendencies. ”
Westford's explanation undoubtedly deepens people's understanding of the nature of the scientific revolution, but its shortcomings are also very obvious. First of all, the meaning of mechanistic philosophy is too broad, including both Descartes' mechanistic theory and Boyle's particulate theory. Second, in this interpretation, the subordination of experiments, either to mathematical Platonism or mechanistic philosophy, is obviously unconvincing.
Albert Einstein famously explained why modern science arose in Europe. The incident began when U.S. Army Colonel Switzer J S, who retired from the army, chose to pursue a history degree at Stanford University and took reading classes with sinologist Wright A F. One of the topics discussed in class was the "Needham problem," so he wrote to Einstein for advice. In his reply of April 23, 1953, Albert Einstein wrote: "The development of Western science is based on two great achievements: the invention of the system of formal logic by the Greek philosophers (embodied in Euclidean geometry) and the discovery (of the Renaissance) of the possibility of revealing causality through systematic experiments." In my opinion, it is not surprising that the Chinese sages failed to take these two steps. Amazingly, these discoveries were made. ”
Einstein's intuitive understanding suggests that a rational explanation of scientific revolutions must take into account formal deductive systems and systematic experiments. This is the explanation of the chronology of the third generation of historians, that is, Floris Cohen's "fusion of three ways of knowing".
Flores Cohen argues that before the rise of modern science, there were three "ways of knowing nature" or "forms of natural knowledge" (form der naturerkenntnis), namely the Alexandrian way of knowing (the abstract-mathematical way), the Athenian way of knowing (the way of natural philosophy), and the European way of knowing (the systematic way of observing and experimenting) that arose during the Renaissance. Among them, the philosopher's approach is to explain natural phenomena from the top down by establishing first principles and then applying a deductive approach, and the representative achievements are the atomic theory of ancient Greece, Plato's co-phase theory, and Aristotle's natural philosophy. Mathematicians used mathematical models to characterize natural phenomena, with notable achievements such as Greek planetary astronomy, Archimedes' statics, and geometric optics. The way of observation and experimentation is actually derived from the engineering tradition, which emphasizes that truth cannot be derived from the intellect, but is to be found in precise observation and experimentation.
Based on this program, Floris Cohen believes that the integration of these three approaches is done gradually. Galileo and Kepler introduced the philosophical way of knowing into the mathematical way of knowing, emphasizing that their work was in line with the philosophical ideas of Plato-Pythagoras. Descartes introduced the mathematical way of knowing into the philosophical way of knowing, emphasizing that the motion of particles must obey the mathematical laws of mechanistic theory, especially the three laws of motion: the law of inertia, the law of collision and the theorem of centrifugal force. The fusion of philosophical and experimental ways of knowing is first and foremost due to Boyle and Hooke. In the 17th century, there was no word for a "scientist", so Galileo called himself a "mathematician-philosopher" and Boyle called himself an "experimental philosopher". The perfect fusion of the three ways of knowing was finally completed by Newton. Newton was not only a philosopher, a mathematician (the inventor of calculus) and an experimenter (such as the famous Newton's ring experiment), but also a true "scientist" who integrated these three ways of knowing, as the title of his book "Mathematical Principles of Natural Philosophy" demonstrates.
Floris Cohen's explanation of the scientific revolution is by far the most natural and plausible explanation of the rise of modern science. According to this interpretation, modern science is essentially the most perfect combination of ontological commitments, abstract representations, and systematic experimentation. This combination first took place in the 17th century, and the result was the rise of modern science.
Dynamic models of scientific progress
Just as Kovaret's view of scientific revolution inspired Kuhn's paradigm theory, Flores Cohen's explanation also sheds light on the dynamics of scientific progress. According to Flores Cohen, Newtonian mechanics is a combination of philosophical, mathematical and experimental ways of knowing, in which the philosophical way of knowing establishes the ontological basis of the theory, that is, the basic beings (including absolute space-time, particulate matter, and super-distance interactions) promised by the theory; The mathematical way of knowing is an abstract representation of the theory that is built; The experimental approach provides empirical support for the theory.
Floris Cohen's explanation coincides with Quine's characterization of the structure of scientific knowledge. Quine argues that the periphery of scientific knowledge is the empirical statement, the subject is the theoretical statement, and the core is the ontological commitment. The only difference is that Quine replaces knowledge in the mathematical form of Floris Cohen with theoretical knowledge. Theoretical statements are certainly not limited to mathematical propositions. Different disciplines have different ways of representing theories. Physics is mainly characterized by mathematics, and chemical and biological theories are usually characterized by models. Chemical reaction equations, molecular structure models, evolutionary lineage trees, gene maps, etc., are all abstract models of structural relationships between theoretical entities.
Referring to Quine's terminology, Flores Cohen's explanation can be expressed as follows: the essence of the scientific revolution in the 17th century was the process of disconnection and harmony between belief (the ontological promise that people believe in fundamental beings, especially metaphysical entities that transcend sensory experience), theory and experience. Belief is the cornerstone of a scientific theory, and experience is the constraint of a scientific theory. Any scientific theory requires the greatest harmony of beliefs, theories, and experiences. The unique significance of the scientific revolution in the 17th century was that, for the first time, belief, theory, and experience formed an inseparable triangular structure.
Once this structure is formed, science has an internal motivation for self-correction and self-evolution. This is because, due to the plurality of beliefs, the expansiveness of experience, and the equivalence of theoretical representations, the state of harmony between the three will always be broken. The subsequent scientific revolution comes from the internal tension between the three. The disconnection or inconsistency of any two of the three of beliefs, theories, and experiences can lead to scientific progress and even scientific revolutions.
The relative independence of beliefs, theories and experiences, especially the plurality of beliefs and the expansiveness of experience, is the fundamental reason for the internal tension between the three. The relative independence of empirical exploration is most typical of unexpected experimental discoveries, such as Brownian motion and the discovery of cosmic microwave background radiation. The relative independence of theoretical development is mainly reflected in the fact that the same theory can have multiple equivalent expressions, such as Newtonian mechanics and analytical mechanics in classical mechanics, matrix mechanics and wave dynamics in quantum mechanics. The relative independence of belief is exemplified by the rejection of the role of distance by Leibniz, Maxwell, and Einstein. According to this, scientific progress can be divided into three types: belief-driven, theory-driven, and experience-driven.
1) Belief driven: theoretical or experimental advances based on aesthetic and metaphysical ideas. The aesthetic factor is mainly embodied in the pursuit of the simplicity of the theory itself and the compatibility between the theory, and the metaphysical belief behind it is the simplicity, symmetry and unity of nature. The establishment of special relativity, general relativity, and relativistic quantum mechanics are all the result of this belief. Metaphysical concepts mainly refer to ontological conceptions of reality, such as Newton's assumption of the super-distant force between particles, Faraday's assumption of induced lines of force (Fig. 4), Mendel's assumption of genetic factors, and Einstein's assumption of gravitational space-time geometry. The conception of reality, as the basis of theoretical representation, not only promotes the construction of theory, but also stimulates the development of experimental work. Maxwell et al.'s idea of the ether inspired Michelson-Morey to design experiments to test the second-order effect of the ether; De Broglie's idea of a wave of matter led Davisson C J and Germer L H to carry out electron diffraction experiments.
Fig.4 Faraday's assumption of magnetic field lines
2) Theory-driven: the change of beliefs and the progress of experiments brought about by the progress of theory. After establishing the three laws of planetary motion, Kepler then assumed that there was a long-range attraction similar to magnetic force between the sun and the planets. Based on his equation of electromagnetic field, Maxwell confirmed that light is an electromagnetic wave. These are all beliefs shifts that are caused by theories. Most of the experimental research in the history of science has been conclusive experiments driven by theory. Galileo's inclined plane experiments, Hertz's experiments on electromagnetic waves (Fig. 5), and Eddington's experiments on light deflection (Fig. 6) were all designed to test these theories.
Fig.5 Hertz's experiments on electromagnetic waves in 1888
Fig.6 Eddington's light deflection experiment in 1919
(Image source: spaceweather.com)
3) Experience-driven: the change of beliefs and the development of theories caused by the progress of experiments. Faraday proposed the concept of magnetic field lines based on an experimental demonstration of the distribution of iron filings around a magnet, which is a prominent example of experientially stimulating beliefs. Experiment-driven theoretical changes are innumerable in the history of science. Kepler set out to revolutionize astronomy by assuming that the orbits of the planets were elliptical rather than circular, because of the slight error between Ptolemy's model of the circle and Tycho's observations. Planck proposed Planck's formula to fit the blackbody radiation spectra measured in the infrared region by two groups at the Imperial Institute of Physics and Technology in Berlin (Figure 7), thus beginning the quantum mechanical revolution. Watson and Crick's double helix model relies on Chargaff E's experiments on DNA base composition and Franklin Ree's X-ray diffraction images of DNA crystals.
The establishment of any scientific theory is not achieved overnight. In the process of scientific development, these three driving methods often play an alternate role. In the minds of scientists, beliefs, theories, and experiences are always in a dynamic process of adaptation. Take, for example, the establishment of classical genetics: Mendel's path is the theory of belief → empirical →, while Morgan's path is the theory of empirical → belief →. Mendel's idea of genetic factors led him to conduct pea hybridization experiments, which led to the discovery of the two laws of classical genetics (the law of separation and the law of free combination). Morgan did not accept the idea of genetic factors at first, but the results of his fruit fly hybridization experiments were in line with Mendel's law, which forced him to accept Mendel's idea, and then discovered the third law of classical genetics (the law of linkage and exchange of genes). Further, he collaborated with his disciple Sturtevant A H to establish a mapping of genes by measuring the distance between two genes on a chromosome by experimentally determined recombination frequencies (Figure 8), thus perfecting classical genetics.
Fig.7 Blackbody radiation experiments in 1900
Fig.8 Drosophila gene map of Steven Eventant
The complex interaction between the three driving modes is more obvious in the development of electromagnetism theory. Let's start with Oster's experimental discovery in 1820. Previously, the connection between electricity and magnetism was not well known, and the force between charges was considered to be the force acting at a distance (Coulomb force). There is a clear disagreement between British and French scientists on how to understand the Oersted effect: Ampère believes that the essence of magnetism is a toroidal molecular current, and the effect of the current on the magnetic poles is the overdistance effect between the current elements; Following this concept, two scientists in France established the Biot-Savar law of the interaction of electric currents. At the same time, the British scientist Wollaston (Wollaston W H) believed that a circular distribution of "magnetic fluid" is generated around the energized wire, which deflects the magnetic poles of the magnetic needle. Inspired by this, Faraday proposed based on experiments on the distribution of iron filings around energized wires that the action of the current on the magnetic needle is realized by the magnetic field lines distributed in space. Believing in the symmetry of electricity and magnetism, Faraday discovered the phenomenon of electromagnetic induction in 1831 and explained the generation of induced currents by the change in the number of magnetic field lines passing through the coil. This historical sketch shows that the same experiment led to two different beliefs, and thus two different theoretical and experimental approaches: the Biot-Savar law from the over-distance action approach, and the electromagnetic induction law from Faraday's line of force approach. Interestingly, the original mathematical formulation of the law of electromagnetic induction was treated in terms of the over-distance interaction (electrodynamic potential) between current elements. Everyone knows the end of the story: Maxwell saw the lines of force as a figurative representation of the field, and the field as a wave of the ether, and established the kinetic theory of the electromagnetic field.
The above cases show that scientific progress does not come from a conflict between paradigm (belief or theory) and experience (experimental results), as Kuhn's paradigm theory suggests; Nor is it simply the selective effect of "iron laws" on existing theories, as Stravings's theory of the knowledge machine asserts. From the perspective of theory, it can be seen that the major progress of scientific theory comes from the joint impetus of belief and experiment.
Comparison with existing theories
A dynamic model based on the interaction between beliefs, theories, and experiences can avoid the inherent limitations of Kuhn's paradigm theory and Stravings's knowledge machine theory and the resulting lack of explanatory power. We call this model the "dynamic model" and compare it to Kuhn's paradigm, Stravings's knowledge machine, and Quine's "web of belief."
Compared with Kuhn's theory, the dynamic model is equivalent to decomposing Kuhn's generalized paradigm into two parts: belief and theory. The significance of this distinction is that theories belong to the community of scientists, while beliefs belong to individual scientists. In this way, the problem of the coercion and the problem of incommensurability of the paradigm can be avoided. When an individual scientist accepts a theory, he or she can take a reservation about the ontological promise of it, i.e., accept the theory as a "superficial explanation" of natural phenomena.
The problem of generality between paradigms can also be reasonably explained in the dynamical model. The replacement of scientific theories only revises the original ontological conception to a certain extent. Take, for example, the development of physics. In Newtonian mechanics, the basic theoretical entities include absolute space-time, particulate matter, and over-distance forces. In Maxwell's theory of electromagnetism and special relativity, Min's space-time as a whole remains straight, homogeneous, and absolute (i.e., independent of matter and interactions). The only difference between Min's space-time and Newton's space-time is the relativity of simultaneity. The concept of particulate matter and gravitational interactions are also retained, with the addition of electromagnetic fields that are both matter and transport interactions. The two major physical revolutions of the 20th century, the general theory of relativity and the quantum mechanical revolution, respectively revised the view of space-time and the view of matter in the special theory of relativity. The general theory of relativity retains the classical view of matter, but greatly revises the view of space-time of the special theory of relativity: space-time is no longer the stage of matter activity, but the result of the distribution and movement of matter, and the geometric properties of space-time directly represent gravity. Nevertheless, given the distribution and motion of matter, the geometry of space-time is rigid; And on a local scale, based on the principle of equivalence, special relativistic physics is fully applicable. On the other hand, quantum mechanics (and quantum field theory) retains the space-time view of special relativity, but modifies the classical view of matter: the state of a physical system is described in quantum states, thus exhibiting "wave-particle duality". Whether from Newtonian mechanics to quantum mechanics, or from the theory of gravitation to general relativity, theories are at least partially reducible.
Kuhn's theory lacks explanatory power mainly because it focuses on the conflict between paradigm (belief + theory) and experience. This has two serious consequences: First, it fails to explain the shift from "pre-paradigm" to "paradigm". The scientific revolution of the 17th century and the "second scientific revolution" mentioned by Hakin and Mendel's genetics revolution are all revolutions from the pre-paradigm to the paradigm; Second, it does not explain the absence of "abnormal" scientific revolutions, including the revolution in general relativity, evolution, and molecular biology. The general relativity revolution was to reconcile the results of Newton's theory of universal gravitation and special relativity. Darwin's evolutionary revolution and Watson-Crick's revolution in molecular biology are both based on new empirical facts to solve the serious shortcomings of the old theories, so that they have made a qualitative leap forward, and there have been no anomalies and paradigm shifts.
From the point of view of dynamic models, none of the above revolutions is difficult to find a reasonable explanation. From pre-paradigm to paradigm, it is the result of both experiment and belief, and the establishment of electromagnetism theory can be exemplified. The general theory of relativity was not created to explain the anomaly of Mercury's perihelion, but to pursue self-consistency between theories. Darwin's evolutionary revolution did not overturn the common ancestor theory of the old evolutionary theory, but proposed the mechanism of the emergence of new species and the evolutionary genealogical tree structure based on the avian characteristics of the Galapagos Islands (Figure 9). The molecular biology revolution is based on new experimental results that advance genetics from the cellular level to the molecular level.
Fig.9 Darwin's notes on species evolution delineate the evolutionary phylogenetic tree structure for the first time
(Image source: Cambridge University Library, cudl.lib.cam.ac.uk/view/MSDAR-00121/38)
Compared to Strevins's knowledge machine, the dynamics model places the process of discovery as much as the process of confirmation. As a refined empiricism, knowledge machine theory, like traditional logical empiricism, sees the process of discovery as an inspired, inexplicable process. In the dynamic model, the establishment of theories is the result of both experience and belief, in which beliefs may come from traditional metaphysics or new ideas inspired by experiments. In other words, although the process of discovery has a certain space for free imagination, it must be guided and constrained by experience and belief.
The establishment of the special theory of relativity is the best illustration of this. Einstein's special theory of relativity is a perfect combination of aesthetic and empirical vision. Einstein's dilemma at that time was that the principle of relativity, the principle of invariance of the speed of light, and the Galilean transformation were incompatible, so should the principle of relativity and the principle of invariance of the speed of light be retained, or should the principle of relativity and the Galilean transformation be retained? Einstein chose the former for simplicity because he believed that Maxwell-Lorentz's theory should be true in all inertial frames, not only in absolute frames of reference (the aetheric system at rest). So what about the Galileo transform? To do this, he resorted to empirical evidence, recognizing that time is dependent on measurement, that the calibration of clocks depends on optical signals, and therefore simultaneity is relative. Only with the addition of experimental provisions for the measurement of time and position was Einstein able to derive the Lorentz transform from the principle of special relativity and the principle of invariance of the speed of light.
The creation of the general theory of relativity can better reflect the power of belief. Beliefs here include both general metaphysical ideas, such as belief in the simplicity, symmetry, and unity of nature, and specific metaphysical ideas, such as assumptions about time, space, matter, and interacting forces. Einstein's goal was to resolve the incompatibility between Newton's theory of universal gravitation and special relativity. In 1907, Einstein laid the first cornerstone of the general theory of relativity, the equivalence principle: a free-falling observer does not feel gravity, so gravity is equivalent to inertial force at least on a local scale. In 1912, Einstein found the second cornerstone of the theory: in a rotating coordinate system, the ratio of the circumference to the diameter of a circle is less than π due to the Lorentz contraction in the direction of motion. Since gravity is equivalent to a non-inertial frame, and Euclidean geometry in a non-inertial frame no longer holds, gravity can be described in terms of the gauge of space-time. This also shows that Einstein's profound thoughts have always been tightly tied to the rock of experience.
By considering only the process of confirmation, knowledge machine theory not only excludes the deep thoughts of individual scientists, but also limits the role of experience to the testing and selection of theories. In the dynamics model, the role of experience is reflected not only in the confirmation but also in the discovery. Based on the interaction between beliefs, theories and experiences, the process of discovery and the process of confirmation are mutually reinforcing.
The idea of scientific knowledge as a fusion of beliefs, theories, and experiences is actually borrowed from Quine's theory of the "web of beliefs". Quine argues that the totality of human scientific knowledge is a web of beliefs, with experience at the periphery, theory at the inside, and logic and metaphysics at its core. "The totality of our so-called knowledge or belief," he said, "from the most fortuitous geographical and historical events, to the most profound atomic physics and even pure mathematical and logical laws, is only an artificial fabric that remains in close contact with experience along the periphery." Or, to put it another way, the whole of science is like a force field, and its boundary condition is experience. The clash of the surroundings and experience in the presence causes internal readjustment. ”
Any scientific theory has some kind of ontological position that contains ontological assumptions that acknowledge the existence of this or that thing. Quine argues that the problem of ontological commitment in a theory is the question of what is in accordance with that theory. The relationship between ontological commitment and experience, like the relationship between theory and experience, is to rationalize or explain empirical facts: "Our acceptance of an ontology is in principle similar to our acceptance of a scientific theory, such as a system of physics." At least to the extent that we are reasonable, we have adopted the simplest conceptual framework that can be combined and arranged from the original experience of scattered fragments of disorder. ”
Quine argues that scientific knowledge is judged by experience as a whole. It is the totality of knowledge that is empirically tested, not just the propositions that are closer to the edge. That is to say, both beliefs and theories must be subject to experience. He also emphasized that empirical evidence is underdetermination for the overall determination of knowledge. Within a given range of experience, it is entirely possible to have an empirically equivalent theory. Adjustments to beliefs or theories based on experience are best done with minimal disruption to existing belief systems.
Quine's theory of the web of belief is not a specific theory of scientific progress. But the insights it contains, such as the ontological promise of scientific theory, the constraining effect of experience on the totality of knowledge, and the optimal way for beliefs and theories to adjust to experience, are important for our understanding of scientific progress. The dynamic model of this paper, that is, that the goal of scientific progress is to achieve the greatest harmony between beliefs, theories, and experiences, is largely derived from Flores Cohen's historiographical program, but also draws on Quine's ideas and terminology.
As a descendant of logical empiricism, Quine is concerned with the static structure and empirical confirmation of scientific theories. Therefore, in Quine's theory, experience plays only a negative restraining role, rather than a positive guiding role. The goal of Quine theory is to describe the logical structure of scientific knowledge, not its dynamic evolutionary mechanism. Looking at science from a static point of view, it is easy to exaggerate the degree of freedom of "non-sufficient decision". From the perspective of development, the theory of empirical equivalence, with the expansion of empirical research, is often no longer equivalent. The Copernican and Ptolemaic systems were empirically equivalent in the middle of the 16th century, but by the beginning of the 17th century they were no longer equivalent. Theories that are empirically equivalent, if they are only mathematically equivalent but not physically (especially ontologically), sooner or later have to accept the empirical verdict, and there will be what Stravins calls "Bacon convergence". Scientific progress can only be truly understood by starting from the dynamic adjustment between beliefs, theories, and experiences.
conclusion
The pattern of scientific progress, which is commonly referred to as the "law of scientific development". In this article, I propose a dynamic model of scientific progress based on Floris Cohen's explanation of the scientific revolution in the 17th century, and Quine's analysis of the overall structure of scientific knowledge. According to this model, scientific progress is a dynamic process in which beliefs, theories, and experiences move from disjointed or conflicting states to interrelated and mutually adaptable.
Quine's web of belief theory aims to describe the logical structure of scientific knowledge, which is equivalent to the statics of science. Floris Cohen's explanation of the scientific revolution in the 17th century merely describes the historical process of the gradual convergence of three currents, which is equivalent to the kinematics of scientific progress. Statics is concerned with the state of equilibrium between beliefs, theories, and experiences, while kinematics is concerned with the trajectory of convergence between beliefs, theories, and experiences. In contrast, dynamics emphasizes the evolutionary mechanism of mutual drive and adjustment between beliefs, theories, and experiences.
Compared with Stravings's knowledge machine, the dynamics model places the process of discovery and the process of confirmation on an equal footing, and shows that the two types of processes are interconnected and mutually reinforcing. The process of discovery is not an irrational process that cannot be explained, but a process of rationalization under the guidance and constraints of experience and belief. The noble goal of science, as Albert Einstein put it, is to "paint a simplified and comprehensible picture of the world in the most appropriate way", rather than to be satisfied with a mere "superficial explanation" of nature. The belief in the simplicity of nature, as well as the rational ontological commitment, are important forces for theoretical progress, as evidenced by the creation of special and general relativity.
Compared with Kuhn's paradigm, the dynamic model disassembles the "generalized paradigm" into two parts: belief and theory, thus not only eliminating the problem of the coercive and irreducible nature of the paradigm, but also explaining the scientific revolution that does not originate from the "abnormal". Newtonian mechanics, Maxwell's theory, and Mendelian genetics are all revolutions that create "paradigms" driven by a combination of experience and belief. The revolution in special relativity and general relativity is mainly a "paradigm shift" driven by belief to solve the incompatibility between existing theories. Darwin's evolutionary revolution and Watson-Crick's revolution in molecular biology were mainly driven by experience, which made a qualitative leap forward in the old theories. If Kuhn had to use Kuhn's terminology, it could only be described as a "paradigm upgrade". The "paradigm shift" caused by the "abnormality" is only one of the paths of the scientific revolution.
The relative independence of beliefs, theories, and experiences, especially the expansiveness of experiments, is the fundamental reason for the internal tension between the three. According to this, scientific progress and scientific revolution can be divided into three different types: belief-driven, theory-driven, and experience-driven. It is beyond the scope of this paper to predict future scientific revolutions based on dynamic models of scientific progress, combined with an examination of contemporary scientific frontiers.
About author:Hao Liuxiang is an expert in the philosophy and history of science. He is currently the head and professor of the Department of Philosophy of the University of Chinese Academy of Sciences, and the head of the Institute of Philosophy of the Chinese Academy of Sciences. His research interests include the history of scientific thought, scientific revolution, and philosophy of physics.
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