Briefly describe Popper's basic views on the scientific development model of falsificationism.

The pillar of Popper's philosophy is his philosophy of science, which he calls "critical rationalism" and sometimes "falsificationism".

First, the criticism of inductive doctrine.

Popper is a fierce anti-inductive person, and his empirical falsification principle is based on his criticism of inductive theory. Popper called philosophy of science "the logic of scientific discovery", that is, the method of analyzing empirical science. He pointed out that the characteristic of empirical science lies in its method, but this method is not the induction advocated by empiricism. Popper believes that induction does not exist at all, and it is impossible to generalize general statements from singular statements. He cited three examples: (1) The sun used to rise and set every 24 hours, but now it has been overthrown by the Masai who discovered the "midnight sun" in the Biday River. (2) "Several people will die" or "every generation of creatures will die" has been denied by bacteria (cancer cells) to divide and reproduce themselves without dying. (3) "Bread gives people nutrition", but it was refuted because of ergot poisoning in rural France. The above three examples show that induction can only tell people the past, but not the future. He thinks that the principle of induction is groundless, and it is the principle of deducing the future from the past. Inductivism proves this principle by induction, in fact, it is to prove itself with arguments to be proved. Popper not only opposes the traditional induction that can ensure us to acquire the necessary knowledge, but also opposes the logical positivism that induction is possible. The reason is: (1) past repetition cannot guarantee possible repetition in the future, and it may not be repeated in the future. Because of its rotation, the earth rises in the east every day, and one day, the earth will be destroyed, so it will not be repeated. (2) From a mathematical point of view, no matter how many times it is repeated in the past, it is only a limited number, and the future is infinite. The ratio of finite number to infinite number can only be zero, and finite cannot represent infinity.

Based on the above reasons, Popper believes that induction is not a scientific method, which can neither give people knowledge of future inevitability nor future probability, and people should exclude it from the field of scientific research. It should be noted that Popper's criticism of induction is basically correct, because without deduction, pure induction can't really provide people with the necessary knowledge, but by denying the role of induction, it separates the internal relationship between induction and deduction in dialectical thinking and moves from one extreme to the other.

Second, the principle of empirical falsification.

Since induction is not a scientific method, what is the empirical scientific method? Popper thinks it is hypothesis and deduction. The task of science is to construct hypotheses or theoretical systems, and then test them with observations and facts. This kind of test is not to prove the theory to improve the probability of hypothesis, but to improve the testability of hypothesis and increase the experience content. It is on the basis of anti-induction that Popper put forward the famous "empirical falsification principle" against the "empirical confirmation principle" of logical positivism.

Popper believes that scientific theories or propositions cannot be proved by experience, but can only be falsified by experience. This is because any scientific theory has universal validity, so the statement of any scientific proposition must be a universal proposition or a full name proposition. Such as "any two objects will generate heat when rubbed" and so on. However, the facts observed from experience are individual statements or propositions. Because we can't promote the individual to the general by induction, and we can't confirm the experience by confirming the individual. Just as people can confirm that "this swan is white" by observation, they cannot confirm that "all swans are white". So "a theory is logically impossible to be confirmed by experience". Popper denied induction, and induction also denied the empirical verifiability of experience to scientific theory.

Popper went on to point out that although experience cannot falsify the universal theory of science through individual propositions, it can falsify the universal theory of science through falsification of individual propositions. Because any individual can overturn the full name proposition as long as it does not conform to the general generalization. For example, although experience cannot confirm the universal proposition that all swans are white, it can falsify "this swan is white" or "that swan is white" and "all swans are white". Confirmation is impossible, because induction cannot guarantee that the truth of the premise will be passed on to the conclusion; Falsification is possible because it is a kind of deductive reasoning, a kind of reasoning that denies the latter, and the falsity of the conclusion will definitely be passed on to the premise. It adopts deductive method and is represented by symbols: if T, then P; Because it's not p, it's not t.

Popper opposes the empirical confirmation principle of logical positivism and emphasizes the asymmetry of empirical confirmation and empirical falsification of universal propositions, which is reasonable. But on the issue of confirmation and falsification, he exaggerated the relativity of confirmation and the absoluteness of falsification. In fact, under certain conditions, the same theory may be falsified by practice, and under another condition, it may be confirmed. Only in the process of constant practice, through constant falsification and confirmation, can the theory move from relative truth to absolute truth.

Three. Demarcation standard

Based on the principle of empirical falsification, Popper put forward a demarcation standard (criterion) which is different from logical positivism. He is talking about the demarcation between science and non-science. Logical positivism holds that the demarcation standard between science and metaphysics is the principle of empirical verification: that is, any proposition that can be verified or denied by experience is scientific, otherwise it belongs to metaphysics. Popper, on the other hand, believes that scientific propositions cannot be proved at all, but can only be falsified. Therefore, the demarcation standard between science and non-science is not the principle of empirical verification, but the principle of empirical falsification. He said: "A proposition is scientific because it can be tested or falsified by experience. On the contrary, it belongs to the metaphysical side.

Falsifiability mentioned by Popper here refers to falsifiability in logic, that is, any proposition or theory that can be falsified by experience in logic is a scientific theory. This includes theories or propositions that have been falsified by experience in history, such as geocentric theory and phlogiston theory. And theories that have not been falsified so far, but may be falsified by logic in the future, as well as absolutely correct theories or propositions, which he thinks are unscientific propositions or theories. According to this demarcation standard, Pope thinks the following proposition is unscientific.

1. tautological propositions and numerical propositions

For example, "a bachelor is an unmarried person" is just a synonym replacement; And "2+2=4" belongs to tautology, does not express any empirical content, can not be falsified, logically holds forever, so it is unscientific.

2. Logically, all possible propositions are listed.

For example, "Will it rain here tomorrow?" This proposition exhausts the situation of things and cannot be falsified.

3. Metaphysical propositions and religious myths

For example, the relationship between matter and consciousness, which is beyond experience, cannot be confirmed or falsified by experience, is also a non-scientific proposition. Religious myths, like metaphysical propositions, belong to non-scientific propositions beyond experience.

4. Pseudoscience

Although they are talking about experience, their words are ambiguous and their judgments are ambiguous, so they cannot be falsified by experience, so they are unscientific, such as astrology, physiognomy, Freud's psychoanalysis and so on.

5. The demarcation standard of "Falsification Principle" itself cannot be falsified by experience, so it also belongs to metaphysics.

Popper believes that the demarcation between science and non-science is not absolute, but relative, and they can be transformed into each other. Some metaphysical theories, due to the change of scientific and technological conditions, can be transformed into scientific theories, such as ancient atomism and evolution. It is reasonable for Popper to see that the boundary between science and non-science can be changed while holding the demarcation standard that has been falsified by experience. But he confused the correct scientific theory (such as Heliocentrism) with the wrong theory (such as geocentric theory); Excluding theories that originally belonged to science, such as mathematics, from the scientific field shows that his demarcation standard is unscientific.

Popper also opposed logical positivism, arguing that metaphysical propositions are meaningless and should be excluded. Logical positivism equates demarcation with meaning, and takes the principle of confirmation as both the demarcation standard and the meaning standard. It holds that only scientific propositions that have been proved or falsified by experience are meaningful. Popper believes that demarcation and meaning are two different issues and cannot be confused. Scientific propositions are meaningful, but metaphysical propositions are not meaningless. Because any scientist must have a certain ontological view, that is, metaphysical view, as the guidance of methodology. He thinks it is shallow to call metaphysics meaningless nonsense. Without any pure speculation and sometimes even very vague metaphysical beliefs, scientific discovery is impossible.

On the issue of metaphysics, Popper claimed to be a realist. He insists on realism, that is, it is positive to admit that there is a material world beyond experience. This is because, in his view, realism is of positive significance. First of all, realism is of guiding significance to scientific research. The task of science is to seek objective truth. If we deny the objective world, scientific research will become a subjective game, and scientists will not have a positive, serious and serious scientific attitude.

Secondly, realism is of positive significance to life attitude. If we deny the existence of the objective world, life will become an empty dream, then who will hold a positive attitude?

Finally, realism is of positive significance to social relations and ethical relations. He believes that if we deny that there are others besides me, no one will care about the sufferings and joys of others, and there will be no ethics at all.

Although Popper supports realism, he has repeatedly stated that he supports "metaphysical realism", that is, he believes that this realism has no scientific basis or epistemological basis, and it has only one necessary assumption, so there is no need to discuss it seriously.

Fourthly, this theory is a bold guess.

(a) Theory precedes observation

Popper denied that theory came from empirical observation and insisted that "theory precedes observation". The basis is as follows: First, scientific observation is purposeful and selective, which is determined by scientists' theoretical views, interests and expectations. He believes that the empirical facts we face are infinitely complex and diverse, and observation can only choose a very limited part. If you want to observe everything, the result is nothing. Therefore, it must be guided by certain theories and viewpoints. Taking himself as an example, he said: I was sitting in my study, and I saw the pen and paper on my desk, the sunlight slanting into the study, the cars flowing in the street outside the window, the shouts of newsboys from far and near ... my mind was full of ideas. What should I record? Observation requires choice. He believes that "our observation is not random photography, but more like a selective painting process". Secondly, we should know something in observation. Observation without understanding is just turning a blind eye, and understanding must be carried out under the guidance of a certain theoretical point of view, which will affect the results of observation. He took the experiment of duck-rabbit diagram in Gestalt psychology as an example to prove that different people have different understandings of the same duck-rabbit diagram. So people always observe everything according to certain expectations.

In a word, Popper followed Kant's transcendental view that reason legislates for nature, and believed that universality and regularity did not come from nature, on the contrary, they were endowed by human beings. But the difference is that he thinks he should criticize rationality and call himself a "critical rationalist".

(2) Science begins with problems.

Popper believes that from the source of knowledge, theory precedes observation, but from the development of science, science begins with problems. This is because theory is a kind of speculation about the universality of nature, and speculation always starts with problems. What's the problem? The problem is that the theory is inconsistent with the observed facts. First, the new observation is inconsistent with the old theory; Secondly, it is the inconsistency between theory and theory; Third, it is the inconsistency within the same theory. It is these problems or inconsistencies that lead people to make scientific exploration and speculation, so there is a theory. So the problem is the starting point of scientific research. Therefore, he denied the traditional concept that science begins with observation and asserted that "theory begins with problems".

(C) Theory comes from inspiration

The theory begins with the question, how is it put forward? Popper believes that it comes from the inspiration of scientists, that is, the general speculation about the problem made by inspiration. There are many bases for scientists to create theories, including predecessors' knowledge and current experience, and the real proposal of theories must rely on scientists' inexplicable inspiration. He said that many great scientists, such as Einstein, acknowledged this inspiration.

Popper believes that "inspiration" is an inexplicable irrational or illogical thing that cannot be explained by logic. It's sudden and mysterious. He equated inspiration with Bergson's "creative intuition" and said that this irrationality was Bergson's "creative intuition".

Theory is a bold guess.

Popper believes that the essence of theory is a guess, a general guess of nature driven by innate expectations; Because only bold guesses are always incorrect, they will be falsified one day and replaced by new guesses, so they are only temporary assumptions. Theories like Newton and Einstein are all the same. Popper denied the absoluteness of truth because he didn't know there was absolute truth in relative truth.

Five, the theory of scientific knowledge growth

Popper believes that the essence of scientific theory lies in speculation and will eventually be falsified. People can't help asking: how to explain the truth of scientific theory? Is there progress in science? If so, what are the signs of progress? What is the model of scientific progress and development? In this regard, Popper put forward "falsifiability" as a standard to measure the theoretical progress.

falsifiability

According to Popper, any theory can be falsified, so it has falsifiability. The degree of this "falsifiability" is falsifiability, which is the theoretical standard to measure the theoretical progress. Because the falsifiability of each theory is different, some theories are easily falsified, and their falsifiability is high; On the contrary, it is low. So, how to judge the theoretical falsifiability? There are two ways to do this. First, compare the universality of information content. If the theoretical expression is more general, its falsifiability will be higher. Try to compare these two statements: a. The orbits of all celestial bodies are circular; All planets have circular orbits. Proposition A is about all celestial bodies, and proposition B is a part of them, so proposition A is easier to be falsified than proposition B, and the falsification degree of proposition A is higher. Try to compare these two propositions: a. The orbits of all celestial bodies are round; The orbits of all celestial bodies are elliptical. Because the definition of "ellipse" is more accurate than that of "ring", the falsifiability of B is higher. In short, the richer the experience of a theory, the higher its falsifiability. Falsifiability is related to the universality and accuracy of the empirical content expressed by the theory.

However, the degree of falsifiability is only the theoretical standard to test whether the theory is progressing. The height of theory falsifiability can only show that it may be advanced. As for whether it is really progress, it depends on whether it can stand the actual test of experience. Only through the test and verification of experience can it be a truly progressive theory. Experience test is the standard of fact.

Popper further pointed out that "verification" and "confirmation" are completely different concepts. "Proof" means to prove that the theory is true in content, always correct in time and will not be falsified. "Verification" is different. It doesn't prove that the theory is true, nor that it is always correct, but that it has withstood the test of experience temporarily. A theory that is verified today may be falsified tomorrow and will be falsified one day. Therefore, any theory can not be confirmed by experience, but can only be temporarily "verified" by experience.

(2) Realism

Since "verification" cannot prove that the theory is truth, what does it prove about the theory? Popper's views on this issue are not consistent. In the early days, Popper regarded the increasing theoretical content as a scientific purpose. Because, he thinks that if scientists sometimes get the truth, it is purely accidental. He doesn't know that this theory is true. The verification of the theory by experience only proves the certainty of the theory. As for the relationship between "certainty" and truth, he is evasive. In 1960s, he put forward the concept of "verisimilitude", which definitely affirmed a kind of "authenticity" or "verisimilitude" of "verification" proof theory. Popper is a realist. He acknowledged the objective truth and thought that the task of science was to seek the truth. However, he opposed the materialist theory of reflection and denied that science could know the truth. Because in his view, the objective world exists outside human experience and cannot be experienced and recognized.

Popper believes that although science cannot know the truth, it can explore the truth. Because, although people can't reflect the objective world, they can guess, that is, make an exploratory guess according to the problem.

Since scientific theory only guesses the world, not reflects it, and it will be falsified by experience sooner or later, is science absolutely irrelevant to truth? Popper thinks not, because it can be close to the truth through constant speculation. Guess and falsify; Guess again, then falsify ... this is the way science approaches the truth. Popper called the essence of scientific theory close to truth "loyalty" and the degree of loyalty "loyalty". He thinks that different theories have different faithfulness. The more advanced the theory, the higher the fidelity. The process of scientific development is the process of improving theoretical fidelity, and there is no end. Popper believes that the greatest fidelity of science is "just a distant and unattainable ideal". This is because the theory guesses nature, not reflects it, and cannot be absolutely correct; The world is infinite, and science has no ultimate development.

In a word, in Popper's theory of truth, there are many reasonable points, as well as many inconsistencies and confusions, and the root of his mistakes lies in his subjective empiricism.

Six, the mode of scientific development

Popper believes that the growth of human knowledge is manifested in scientific progress, which is a process in which new theories constantly replace old ones, not just the accumulation of knowledge content in quantity. He said that people usually like to compare human knowledge to a magnificent building, and the growth of knowledge is like gradual construction on a solid foundation. But this is an inappropriate metaphor. Because human knowledge has no fixed foundation, the growth of knowledge is not based on the structure of existing knowledge, but on the destruction of existing knowledge; Moreover, the process of breaking old knowledge and building new knowledge is embodied in the same process, which cannot be compared with tearing down old houses and building new ones. It is precisely because Popper's model of scientific knowledge growth is different from the traditional concept that he takes the issue of scientific knowledge growth as the main research object. After explaining the boundary and essence of science with falsificationism, Popper put forward a "four-stage" model of scientific knowledge growth.

(A) the "four stages" model of scientific development

Popper summarized the growth process of science as follows: (1) Science begins with problems; (2) Scientists put forward all kinds of bold guesses, namely theories; (3) Intense competition and criticism among various theories, acceptance of observation and experiment, and high-fidelity selection of new theories; (4) The new theory has been falsified by the further development of science and technology, and new problems have emerged ... The above four links are endless. It can be expressed by the formula: P → TT → EE → P …

Here "P" stands for problems, "TT" stands for competing theories, "EE" stands for eliminating mistakes through criticism and inspection, and P stands for new problems. This is Popper's famous "four stages" dynamic model of scientific development.

(2) Trial and error method

Popper pointed out that from the above four paragraphs, we can see that the most fundamental nature of science is conjecture and refutation, and the most fundamental method is "trial and error method", that is, trial and error method. In his view, the scientific trial-and-error method should not only be tried boldly, but also be strictly tested. This is the origin of the motto "try boldly and test rigorously".

(3) Learning from mistakes

Based on the theory of trial and error, Popper believes that three scientific spirits must be advocated to carry out "bold attempt and strict inspection" in science. This spirit includes: first, the spirit of daring to make mistakes. He believes that truth and error are inevitably intertwined, and science can only move forward by constantly eliminating errors. To this end, he put forward a famous slogan: "learn from mistakes." People think that people who devote themselves to scientific research should not be afraid of making mistakes. Science is an experimental undertaking, and mistakes are inevitable. We should make ourselves experts on a specific problem in repeated failures. Second, critical spirit. Popper believes that science develops in competition, and only criticism can advance. "Scientific method is critical method" and "criticism is the main driving force of any rational development". He not only encouraged scientists to dare to criticize others and authority, but also asked them to dare to criticize themselves. Third, the spirit of negation. Only dare to deny the old theory, can we create a new theory, and we can't establish a new theory without breaking the old one. This kind of denial is not only aimed at others, but also should be brave enough to deny yourself. He encouraged scientists to try their best to deny a theory at the beginning. Einstein, for example, is such a model.

It can be seen that Popper, contrary to the traditional view of scientific static accumulation, emphasizes the critical spirit of science from a brand-new angle, tries to dynamically describe the process of scientific development, summarizes the logic of scientific discovery, reveals the inherent law of scientific development, and emphasizes the scientific method of learning from mistakes. In this way, the research of scientific methodology initiated by logical positivism has greatly promoted and enriched the content of scientific methodology research.

However, Popper used his falsificationism method instead of positivism method to completely deny the rationality of the latter, which is one-sided. In fact, proof method is indispensable in scientific research. Popper denies falsification, but still opposes another new one-sidedness. In addition, Popper's theory of scientific development model also has obvious and serious defects: first, his analysis of "dynamic process of knowledge acquisition" is limited to "dynamic process of knowledge growth" and limited to reconstructing the scientific development process mainly in the logical category of "theory"; One-sided exaggeration of the elimination and abandonment of old theories by scientific development, and denial of the continuous progress of scientific knowledge development. Secondly, the replacement of the old theory by the new theory does not simply abandon the old theory as Popper said, but also includes the supplement, revision and development of the old theory. This ignores the constructive activities of scientific development in normal times. In addition, the replacement of old and new theories is sometimes related to social and psychological factors other than science. Popper did not pay attention to this aspect.