It refers to the interpretation of a phenomenon according to the preset, that is, according to the knownScientific factsAnd scientific principlesnatural phenomenaAndRegularityThe proposed conjecture and explanation, and the data are classified, summarized and analyzed in detail to get a temporary but acceptable explanation.Anyscientific theoryIt shows as hypothesis or hypothesis before being confirmed by experiment.Some assumptions have not been completelyscientific methodIt has been proved that it has not been denied by any scientific method, but it can have a far-reaching impact.For example, German physicists in 1900Max Planck To resolveBlackbody radiationSpectrum and first put forwardQuantum theory(Quantum hypothesis).
People will observe countless facts in their actual life experience.For example, there are rainy days and sunny daysLunar eclipseThere are alsoSolar eclipseMigratory birds return from the north in spring to the south in autumn, waterfalls splash white fog against the rainbow, etc. People not only describe the facts around them, but also understand themscientific theoryTo explain the facts.Whenever people find facts that cannot be explained by the original theory, especially abnormal facts that are contrary to the original theory, they are faced with difficult problems.At this time, people must put forward new theoretical viewpoints to give answers.However, people can put forward different theoretical views on the same facts, and it is difficult to determine which is right and which is wrong.Therefore, anyNew theoryThe initial proposals of the two theories are hypothetical, and their truth needs to be further tested.
scientific researchThe general process of the activity is as follows: when people find some abnormal facts or strange facts that have never been seen before in the actual scientific activities, the original theory and the past explanation methods are useless, so there are problems that need to be solved with new theories and new explanations;Then, people propose new interpretative theories through conjecture, explain relevant facts in new ways, and predict some unknown facts with new theories.This is to build hypotheses to answer questions.Thereafter, more new facts will be accumulated in the process of verifying this hypothesis.The general situation is that only one part of the hypothesis is confirmed and the other part is denied, so the original content of the hypothesis must be partially modified and waiting for new tests.Such reciprocation will gradually lead to the establishment of a system of laws and principles and the formation of aResearch tradition。However, people's understanding does not stop or become rigid, or a new theoretical system and a new research tradition will emerge sooner or later.asAristotleMechanical quiltNewtonian mechanicsAs Newton's mechanics is replaced by Einstein's relativistic mechanics, people's understanding is more and more close to the objective reality.In short, the process of scientific development is the formation of hypotheses,Test of hypothesisAnd the replacement of hypothesis.Therefore, the development form of science is nothing but hypothesis.
Example
Scientific hypothesisIt's about the phenomenon of thingsCausalityOr regular hypothetical explanation.It is used to answer questions raised by facts and can be further tested by facts.for instance:
"Mendel crossed the tall plant variety of edible pea with the short plant variety. The offspring hybrids are tall plantsSelf fertilizationThe number of tall plants and short plants in the descendants is 3 to 1.If thegerm cellIt contains something that contributes to a tall plant, and the germ cell of a dwarf variety contains something that contributes to a dwarf plant, so hybrids should have these two things.Now, since the hybrid is a tall plant, it can be seen that when the two things meet, the tall one is dominant, while the short one is recessive.Mendel pointed out that a very simple hypothesis can explain the 3 to 1 phenomenon in the second generation.When the egg andPollen grainAt maturity, if something that contributes to the height of a plant and something that contributes to the height of a dwarf plant (both exist in the hybrid) are separated from each other, half of the eggs will contain the high element and half of the eggs will contain the short element.The same is true of pollen grains.Two kinds of eggs and two kinds of pollen grains are fertilized at the same opportunity, and the average proportion of three tall plants and one short plant will be obtained. This is because the element height meets the height, which will produce tall plants, and the height meets the height, which will produce tall plants;Dwarfs meet with heights to produce tall plants;When dwarf meets dwarf, dwarf plants will be produced. "（T·H·MorganAuthor: Genetics,Science Press, page 1-2)
Scientific hypothesisIt is a well founded guess of the mysteries of nature, and it is a high expression of human's ability to perceive nature and wisdom.Scientific hypothesis is fundamentally different from such nonsense as ignorance and religious superstition.Any hypothesis is put forward with certain relevant facts as empirical evidence to support it, and also with certain relevant principles as the theoretical premise to prove it.Hypothesis, as a conjecture, isscientific knowledgeIn the soil.
Content system
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Explain the problem
Hypothesis is not put forward for no reason. It is used to answer specific questions and explain certain facts.Therefore, a hypothesis must discuss what kind of problems exist to be solved by people.For example, in the 1860s,AustriaFather Mendel tried to cross peas.High in peasplantVariety and dwarf plant variety, tall plant and dwarf plant are a pair“Relative character”。Take the plants of these two varieties for "parental" hybridization (use tall plants as male parents, and dwarf plants as male parentsfemale parent, or using dwarf plants as male parents and tall plants as female parents), the seeds obtained and the plants grown from them (called "filial generation") are all tall plants.Then, take a generation of plantsSelf pollinationThree quarters of the seeds and plants (called "the second generation of offspring", i.e. the grandchildren) are tall plants and one quarter are short plants. The ratio of the two is 3:1.So the question was raised: why are all the offspring after hybridization tall plants, while the ratio of tall plants to dwarf plants in the offspring after hybridization is always 3:1, Mendel'sRelative character(safflower and white flower, yellow seed and green seed).
Core part
People often use the word "hypothesis" in a narrow sense, which only refers to the supposed theoretical statement.Sometimes people call the supposed theoretical statement "the basic viewpoint of hypothesis".This means that the content of the hypothesis includes the theoretical statement and its interpretation and prediction of the facts, that is, the systematic and complete answer to the problem.For example, Mendel conceived the following theory to answer the question raised in the pea hybridization experiment: the appearance of the organism visible to the naked eye is controlled by the genetic "factors" (later called "genes") in the organism invisible to the naked eye.For example, aGenetic factorThe other genetic factor makes the plant tall, and the other genetic factor makes the plant short, so the "relative traits" of tall plant and short plant are controlled by two different relative genetic factors;Each appearance character of each plant is controlled by a pair of genetic factors, one of which is inherited from the male parent and the other from the female parent.Therefore, these two genetic factors can be the same (called“homogeneityAnd can be different (called "heterojunction").Each plant passes one of the two genetic factors to one seed cell, and each seed cell（gamete）Only one of the two genetic factors is obtained.When the male parent cells and the female parent cells pollinate, the offspring plants have a pair of genetic factors that control a certain appearance character.If the pair of relative genetic factors passed from the male parent and the female parent are different, then one of them will suppress the effect of the other genetic factor, the former is "dominant factor", and the latter is "recessive factor".For example, the factors of tall plants will suppress the effects of factors of dwarf plants, and make this pea appear to be tall plants.Since all the offspring after hybridization of tall plant and dwarf plant have one tall plant factor and one dwarf plant factor, and the dominant tall plant factor suppresses the role of the recessive dwarf plant factor, all the offspring are tall plant;However, recessive factors still exist in the offspring, but their role is suppressed.Therefore, after the offspring with mixed factors pollinate each other, there are four possible combinations: one is the combination of the tall plant factor from the male parent and the tall plant factor from the female parent.The second is the combination of the tall plant factor from the male parent and the short plant factor from the female parent.The third is the combination of dwarf plant factor from male parent and tall plant factor from female parent.The fourth is the combination of dwarf plant factor from male parent and dwarf plant factor from female parent.Of the four possible combinations mentioned above, only the fourth combination can make the plant short.Therefore, the ratio of tall plants to short plants in the second generation is 3:1.In short, Mendel conceived of genetic factors and“Separation law”To answer the question.The separation law of genetic factors is calledMendel's first lawIt is the most basic law of genetics, and can be expressed as follows: a pair of genetic factors do not affect each other in the state of heterogeneous combination (that is, the combination of a dominant factor and a recessive factor)GametogenesisWhen they are completely separated into differentgameteGo to the middle.
Interpret the facts
Explaining a wide range of facts not only shows the ability of the supposed theory to solve problems, but also shows that the supposed theory is supported by a large number of facts.For example, Mendel's genetic factorsSeparation lawCan explain the human eyeIridescenceColoredGenetic phenomenonAnd supported by this fact.
"Blue eyed people and blue eyed peopleMarriage, got the blue eye generation.If a brown eyed man marries a brown eyed man, if their ancestors are both brown eyed, they can only produce brown eyed offspring.If a blue eyed man marries a pure brown eyed man, his children will also be brown eyed.If this kind of brown eyed men and women marry each other, their children will be brown eyed and blue eyed, with a ratio of 3 to 1. "(T · H · Morgan: Genetics,Science Press, page 2-3)
Forecast unknown
A hypothesis must also try to predict new unknown facts.This is not only to show how enlightening the supposed theory is, but also to show that the supposed theory can be strictly tested.For example:
"Mendel used a simple method to test his hypothesis: let hybrid backcross (backcross or backcross is the process of crossing the apparently dominant individuals back with their recessive parents. The purpose is to reveal whether the former is purely dominant or just hybrid)For recessive type, if the germ cell of the hybrid is divided into two types, then the progeny plants should also be divided into two types, each accounting for half.The experimental results are just as expected. "（T·H·MorganOn Genes,Science Press, page 2)
Content structure
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The content of hypothesis is usually very complex.It containsStatement of theory, includingStatement of facts。Moreover, it hasContent whose authenticity has not been determined, andMore accurate content。For example, the 16th centurypolandThe solar system hypothesis put forward by astronomer Copernicus“Copernicus system”It is based on the astronomical observation data available at that time, such as those about planets“Anterograde”And "retrograde movement", among which the description of many observational facts is relatively reliable.The basic theoretical ideas of the Copernicus system include practical contents, such as the earth rotates, the earth and other planets move around the sun, and so on.There are also impractical contents, such as the sun is the center of the universe, the orbits of the planets are perfectly circular, and so on.It should be noted that:
"Copernicus' main achievement is that he first gave a clear and systematic criticism to the geocentrism of the universe, and destroyed the unbreakable insight and visual illusion. This is the biggest revolution he has made. In other aspects, like his predecessors, he still adheres to all aesthetic and philosophical prejudices, and he also believes, like the ancients, that there is a sphericalSmall universe, circumferential orbit andIsokinetic motionBut these assumptions cannot explain the observation, so he had toReintroductionHe has abandoned the Ptolemaic systemEccentric circleAnd this round, he even advocatedAristotleSubstance ofCelestial sphere theoryIn his view, the central sun only has the function of illumination, while gravity is only enough to maintain the internal cohesion of various celestial bodies.In other words, Copernicus' great contribution to science only liberated the literature from the concept of geostationary, thus promoting the future development. As for his interpretation of the movement of celestial bodies, he was not much better than Ptolemy, so there was no progress at that time. In particular, his theory was also confused with many incorrectNon scientificOf the company.If a series of geniuses did not emerge in the 150 years after his death, his work would be completed, and decisive evidence that he had not obtained would be obtained, great progress would not have taken place in astronomy, and his system would not be passed down to today. "([France] Voguler:《A Brief History of Astronomy》，Shanghai Science and Technology Press, page 25)
Hypothesis is human cognitive approachobjective truthThe way."As long as natural science is thinking, its development form is a hypothesis. A new fact has been observed, which makes the way used to explain similar facts useless. From this moment on, a new way of explanation is needed - it was initially based on a limited number of facts and observations.Further observation materials will purify these hypotheses, cancel some, correct some, and finally form laws purely.If we have to wait for the materials that constitute the law to be purified, then it is necessary to stop the research on the application of thinking before that, and the law will never appear. "（《Selected Works of Marx and Engels》Volume III,People's Publishing House, p.561)
Initial stage
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Empirical law
In the initial stage of hypothesis formation, researchers, in order to answer questions of specific natureFactual materialAnd existing theoretical principles, through creative imagination (mainlylogical reasoningAnd make preliminary assumptions.
stayScientific knowledgeThere are different kinds of problems in the process of the formation of different kinds of hypotheses.One is the question raised by the systematization of observable facts.For example, people have observed that crows are black all the time, which leads to the question: "Are crows black?" People have repeatedly observed that swans are white, which leads to the question: "Are swans white?" Such questions also include: "In generalatmospheric pressureIs any pure water frozen when it is cooled to 0 ℃? ""Any solid metal block that rubs against each otherfever"wait.We can put thisClass propertyThe problem of "crow type problem" isEmpirical lawType.The affirmative answer to such questions is to put forward a hypothesis of empirical law.The hypothesis of empirical lawscientific knowledgeThe system ofUniversality of connection, can't understand thisuniversalityIt can be said to be "knowing the truth"Without knowing why”。However, the empirical law can be used to explain the effects that occur in individual facts.
So, how was the initial assumption about the empirical law put forward?The hypothesis of empirical law is always established under the guidance of a certain theory, based on a large number of observational facts, and the interactive application of comparison, analysis, synthesis, generalization and other methods.In general, its initial assumption is mainly based ongeneralizationExtrapolationInspiration ofAnd made.
Everyone is familiar with that when the train comes to us, its flute sound becomes more and more sharp, that isaudio frequencyrise.When the train leaves us, its flute sound becomes lower and lower, that is, the sound frequency decreases.Similarly, a moving light source will change the frequency of light waves just like the frequency of sound waves.If the light source moves towards us, itsSpectral lineWill shift to the high frequency end of the spectrum, that isViolet shift。If the light source retreats away from us, its spectral line will shift to the low frequency end, that isred shift。This phenomenon is called "Doppler Fizeau effect".
Later, astronomers used the Doppler Fizeau effect to determine theApparent velocityBy measuring the size of the shift of a star's spectral line toward the red or purple end, calculate the size of the star'sMovement speedIs the apparent speed.The greater the redshift of a star's spectral line, the greater the speed at which it recedes from us.If the purple shift of a star's spectral line is larger, the speed of the star toward us will be larger.Apply this methodAstronomical observationIt was found that, except for a few recentGalaxy（Local galaxy group）Besides, all galaxies are away from us.The farther away from us, the galaxyred shiftThe greater the amount, the greater the speed of regression.In 1929, the American astronomer Hubble, based on the fact that we have observed local parts of the universe, through comparison, analysis, synthesis and generalization extrapolation, proposed the empirical law:Retrogression speedIs proportional to the distance of the galaxy from us.If a galaxy is twice as far away from us as another galaxy, then the retrogression speed of this galaxy is twice as fast as that of another galaxy.The above empirical law is called“Hubble's theorem”。
It should be noted here that as one of the bases of Hubble's theoremSpectral lineThe explanation of redshift is also a hypothesis, which is derived from the Doppler Fizeau effect.Therefore, things are not classicalInductionismandLogical empiricismAs said, you canscientific knowledgeIts structure is simply reduced to a two-layer model of experience and theory.No empirical laws can be directly observed. They areTheoretical thinkingIncluding the results of application of analogy, imagination, abstraction, idealization and other methods.It's just the role of other methods here, not like generalizationExtrapolationSo direct and so obvious.Therefore, the empirical law should be regarded as a low-level theory.We are in scienceKnowledge networkStructural modelThe empirical law is described in the context of the "crow type question", which is derived from the general extrapolation method.Moreover, as a lower level theory, the empirical law has different levels.As mentioned earlier,Hubble's theoremIs dependent onSpectral lineRedshift phenomenonAnd the explanation of the redshift of galaxy spectral lines depends onDoppler- The empirical law of Fizeau effect.
Theoretical law
So, let's take another look atScientific knowledgeAnother type of question raised in the process of.for instance,Hubble's theoremLater, it was continuously confirmed by new observational facts.Then, the question of how to understand this empirical law will inevitably arise, that is, why are galaxiesRetrogression speedIs proportional to the distance of the galaxy from us?In order to explain Hubble's theorem, people put forwardCosmic expansionHypothesis.At present, astronomers generally believe that the universe is expanding. This understanding is similar to Einstein'sGeneral relativityIt is consistent.Of course, this is not the end of the question. If the universe is expanding, then the following question arises: Why does the universe expand? This must be answered by a higher-level theory. At present, a more popular theory has been formed, namelyBig BangHypothesis.It is related to another theory, the universeSteady stateCompetition.]Another example is whyRelative characterdifferentParental generationHybridizedThe second generation，dominancePerformance and implicit performance always keep 3:1Regularity？For this reason, people put forward the hypothesis of "gene theory" to give answers.It is not difficult to see that the above type of question is not about the universality of some observable connection between phenomena, but about why such a connection is formed.In order to answer this principled question, people must make a hypothesis of theoretical laws and principles.The hypothesis of theoretical laws and principles uses an abstract theoretical "framework" and an idealized "model" to explain the "structure function" of the studied object, so that all relevant empirical laws can be understood, and often further "calibrated" the empirical laws.Undoubtedly, the hypothesis of theoretical laws and principlesscientific knowledgeIn the system of empirical law, it is correspondingly at a higher level than empirical law.The highest level theory is usually called "basic law" or "basic principle".
Then, how did the original assumptions about the theoretical laws and principles be put forward?The hypothesis of theoretical laws and principles explains how to form various connections between things and phenomena（Structure and function）It is not only established by the methods of comparison, analysis, synthesis and generalization, but also by the methods of analogy, conjecture (association/assumption/assumption/imagination), abstraction and idealization.Generally speaking, its initial assumption is mainly based onAnalogyInspired by.Because researchers always use the known picture to imagine another new picture.For example,NetherlandsPhysicist Huygens proposedWave theory of lightThis is the result of analogy with sound waves and water waves.He said:
"We know that sound isCan't see, can't touchAir direction ofsound sourceThe whole space around it spreads. This is a movement in which one air particle gradually advances to the next.Because the propagation of this movement is carried out at the same speed in all directions, it must be formedspherical waveThey travel farther and farther outward and finally reach our ears.Now, no doubt, light also comes fromIlluminantIt arrives at us through the movement of some kind of media, because we have seen that the light from the illuminant to us cannot be transmitted by objects.As we are about to study, if it takes time for light to travel along its path, then this movement transmitted to matter must be gradual. Like sound, it must also travel in the form of a sphere or wave;We call them waves because they are similar to the water waves we see when we throw stones into the water. We can see that the water waves seem to be spreading out in circles, although the water waves are formed for other reasons and only on the plane... "(Quoted from George GagaNever loseAuthor: History of Physics, Commercial Press, page 81)
Another example is that people look at it carefullyWorld map, it is not difficult to findAfricaThe western coastline andSouth AmericaThe eastern coastline coincides with each other, and they can be spliced together into one piece, just like children playing jigsaw puzzle.Why such a coincidence?Since the 17th century, it has been assumed that the two continents were together before they drifted away.It is further discovered that not only South America and Africa can be combined, but alsoNorth AmericaIt can also be combined with Europe.IndiaAustralia、AntarcticaIt can also be pieced together.In other words, it can be assumed that today's several continents are all formed by drifting after the rupture of the original ancient land.Modern times“Continental drift theory”Founders ofAustriaWeigner, a scholar, thought of the scene of iceberg drifting, and was inspired to imagine a lighter rigidContinental plateIt is heavier floating in the crustViscous fluid——MagmaThey are like floating icebergs that are gradually away from each other《Origin of land and sea》, Commercial Press, page 5),AnalogyIt is very enlightening when forming preliminary assumptions.
Undoubtedly, in the initial stage of hypothesis formation, people can associate from different perspectives and make different analogies. Therefore, the preliminary assumptions made are not unique, but several alternative assumptions are envisaged.If we use "E" to represent the statement of fact that was examined and quoted when we put forward the preliminary assumption, and "H" to represent the conjectured preliminary assumption that can explain E, and do not consider the necessary background knowledge involved in the explanation process for the time being, then it is an attempt to put forward the preliminary assumption andDiversityIt can be simply expressed as follows:
E
If H1, then E
If H2, then E
If H3, then E
……
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So, H1 or H2 or H3 or
for instance,PulsarWhy can we send out pulses so regularly?As for the radiation mechanism of pulsars, astronomers have imagined various scenarios that can radiate pulses.These possible scenarios are: pulseKonductraOrbital motion and rotation.The so-called pulsation is to imagine that the whole star will expand and contract from time to time, just like the beating of human heart.It has been known that some stars have changed their luminosity due to pulsation. Such stars are calledPulsating variable star。Therefore, it is natural to think that the radio pulse may also be caused by pulsation;The so-called orbital motion of a binary star is to assume that two stars in the process of rotating around each other, due to mutual maskingCopulatePhenomenon, so that we can observe periodic pulses;The so-called rotation is supposed to rotate like the light beam on the lighthouse.When the lighthouse beam scans the sea surface, it shines on the ship every week, so in the eyes of the people on the ship, it lights up every certain period（Optical pulse）。Such radiation mechanism can be vividly called "lighthouse" radiation mechanism.
Since the preliminary assumption is tentative and diversified, the researchers can only decide whether to accept or reject it after repeated investigation.Taking the previous example as an example, astronomers confirmed after some investigation that if it is pulsation, it is impossible to maintainPulse periodThe extreme stability of the pulsar is impossible to maintain the extreme stability of the swimming period if the binary stars are in orbit. However, the most obvious feature of the pulsar is the high stability of the pulse period, so it is most reasonable to choose the "beacon" radiation mechanism.Generally speaking, the choice of several assumptions is made in the following way (the necessary background knowledge for participation in the inference process is not considered for the time being):
H1 or H2 or H3
If H1, then e1, not e1 (or the possibility of e1 is very small)
Therefore, H1 cannot be established
If H2, then e2, not e2 (or the possibility of e2 is very small)
So, H3, the researcher can select a preliminary hypothesis that can be established or is most likely to be established in his opinion from several tentative assumptions.Above, we analyzed the initial stage of hypothesis formation.
Completion stage
(Completion stage of hypothesis formation)
What is the completion stage of hypothesis formation?At this time, the researchers focus on the established preliminary assumptions,applied scienceThe theory is demonstrated and supported by empirical evidence, so as to enrich and expand it into aStructural stabilitySystem.This is the completion stage of the hypothesis formation process.
In the completion stage of hypothesis formation,Deductive reasoningThe role of is very prominent.The relevant arguments involved in the preliminary assumption must be demonstrated with scientific theory.For example, onlyContinental driftThis simple assumption is not a complete theory. We must further demonstrate the driving force, direction, speed and other related accompanying factors of continental drift.Obviously, these understandings are the results of comprehensive application of multidisciplinary knowledge.Although the initial assumptions are only conjectured and imagined, they are only rooted inscientific knowledgeOnly in this soil can they grow.
In the completion stage of hypothesis formation, researchers not only understand the content of a hypothesis through the demonstration of scientific principles, but also seekEmpirical factTo enrich the content of a hypothesis.This is to explain the known empirical facts widely from the established point of view through the deductive procedure.If there are more facts to be explained, there will be more empirical evidence to support the hypothesis theory.For example, fromContinental driftFrom the point of view of, it can explain the following groups of facts:
——EachContinental blockIt can be put together like a jigsaw puzzle, and the degree of coincidence between the edges of continental blocks is very high.This is the geometric (shape) mosaic evidence of continental drift.
——The traces left in the rock strata indicate that between 350 million years ago and 250 million years ago, today'sArcticOnce a hot desert, today'sequatorThe area was once covered by glaciersLandmassThe climate zone in ancient times is just the opposite of today's climate zone.This isContinental driftOfPaleoclimateEvidence.
When Wegener proposed the idea of continental drift, he systematically explained the above facts.Interestingly, Wegener's attitude towards him“Continental drift theory”A self evaluation method is proposed.He declared:
"The correspondence between the two sides of the Atlantic, that is, the correspondence between the Pap Mountains and the Buenos Aires Mountains, Brazil and Africa on a large gneiss plateauExtrusive rocksedimentary rockCorrespondence with strike line, correspondence between Amorikan, Caledonian and Proterozoic foldsquaternary glaciation Although the correspondence of terminal moraines has not reached a positive conclusion on some individual issues, in general, it provides unshakable evidence for our view that the Atlantic Ocean is an expanded fissure.Although the junction of continental blocks should be confirmed according to other phenomena, especially their contours, it is of decisive importance that the structures of one side are exactly connected with the corresponding structures of the other side at the time of the junction.Just as we pieced together a torn newspaper according to its uneven broken edges, if we saw that the lines of printed words in it were exactly the same, we could not deny that the two pieces of paper were originally connected.If only one column of printed text is connected, we can already speculate that there is a possibility of merging, but now there are n lines connected, the possibility will increase to n timesPower。It is not a waste of time to find out what this means.Just according to our first line, namelyCape MountainsAnd the folds of the Buenos Aires Mountains,Continental drift theoryThe probability of the correctness of the theory of continental drift is 1:10. Since there are at least six different ranks to test, the correctness of the theory of continental drift is of course 106:1, that is, 1000000:1.This number may be exaggerated, but we should remember: independent inspectionNumber of itemsHow significant is it to increase. "（《Origin of land and sea》, Commercial Press, page 50)
It seems that Wegener is quite eloquent.His assessment figures are as striking as the theory of continental drift.Although he said that "this number may be exaggerated", he did not necessarily realize the difference between successfully explaining known facts and successfully predicting unknown facts.It is the latter, not the former, that is of primary importance to evaluate a hypothesis.
In order to show that the theoretical view of a hypothesis is verifiable, and to ensure that the theoretical view of this hypothesis can be strictly verified in the future, researchers should also predict unknown facts according to the theoretical view of the hypothesis during the completion stage of the formation of the hypothesis.Wegener did the same thing at that timeContinental driftIt is predicted that the distance between the two sides of the Atlantic Ocean is gradually increasing.GreenlandAs it continues to drift westward, its longitude distance from Greenwich is also increasing.
In the completion stage of the formation of hypothesis, researchers should finally sort out all the contents of the hypothesis to make it rigorous and systematic.Its hierarchical structure functions like the following model: as the core part of hypothesis, it is conjectured to answer questionsfundamental theoryViewpoint, which is the programmatic content of a hypothesis, cannot be changed. To interpret known facts or predict unknown facts from the perspective of the basic theory of imagination, this is the outer part of a hypothesis, which defends the basic theory of imagination.So this part should be regarded as the basic theory at the core“Protective tape”, is allowed to change.In this way, the hypothesis is "resilient" when it is“Counterexample”When attacked by, only the protective belt was "damaged", but its core was still preserved, which could enable the "protective belt" to continue to "proliferate" and repair.
Formative principle
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Guided by scientific principles
Above, we have examined the basic procedures and means of hypothesis formation.So,Guiding hypothesisWhat are the criteria for forming activities?Undoubtedly, the formation of hypothesis is highly creative, and there is no universally applicable fixed mechanical model and formal rules, but there are enlightening guidelines, including the following:
Scientific hypothesisThe formation of is the expansion and deepening of people's existing cognitive process. It should follow and apply existing scientific theories, and should not contradict the highly confirmed laws or principles in science.However, the original laws and principles are not perfect, especially when a series of contradictions occur between them and new facts, which also exposes the defects of the original theory.The problem istraditional ideasIs a kind ofForce of habitThe deep-rooted "common sense" is the most difficult to break through.This requires a very bold innovation courage, the courage to challenge the "classical theory" and put forward a new revolutionary hypothesis.Without understanding this truth, there will be no great theoretical changes in natural science.For example, in the early 20th century“Continental drift theory”:
"It is said that Wegener wascontinental marginIt is proposed only after the splicing is exactly matchedContinental driftThis is envisaged.If you look closely at the shapes on both sides of the Atlantic Ocean, perhaps anyone would imagine this.However, because the concept that the earth is motionless exists in the minds of ordinary people, some people at that time regarded this simple assumption as very 'anti traditional', which is nothing. "([Japan] Seiya Ueda:《New Earth View》，Science Press, page 5)
However, Wegener boldly turned to the "orthodox"Fixed theoryThe challenge of the earth view led to a revolution in geology and the rapid development of this originally conservative science.Another example is that when Einstein put forward the theory of relativity in the early 20th century, people were shocked: how can the length be shortenedSlower？！What a strange thing it is! How against common sense!However, the hypothesis of relativity is the product of applying existing scientific theories without being bound by traditional views.Germany's excellentTheoretical physicistPlanck said: "General relativity andSpecial relativityIncludedRelative conceptIt was indeed very novel and revolutionary when it was first proposed to physicists.But one fact has never changed, that is, its assertions and criticisms are not intended to oppose the obvious, recognized and proven laws of physics, but only to oppose certain views.Although these views are deep-rooted, they have not been recognized with more evidence than habits. "(See the Universe from Modern Self study, Commercial Press, pp. 40-41)
Based on empirical facts
Any scientific hypothesis has more or less empirical basis.It is not only different from a certain "take for granted" subjective belief, but also different from the romanticScience fiction, but a well founded answer to a question.However, one cannot wait for the fact materials to accumulate comprehensively and systematically before establishing a hypothesis.Because that is bound to stop the research activities of theoretical thinking, so science is difficult to develop.Moreover, researchers do not have to dare to put forward hypotheses because there are individual "counterexamples" or "outliers".Because the factual materials may also be fallacious, Mendeleev proposed in the 1860sPeriodic law of elementsThere are only 63 known elements.However, he did not wait for all chemical elements to be discovered before discussing the periodic law, nor did he wait for some elementsAtomic weightInstead, we first set up a hypothesis and apply the periodic law to predict unknown elements and their properties.
"The reason why Mendeleev became a great discoverer was that he had great courage and wisdom. He believed that the atomic weight of certain elements could not adapt to his periodic system because of errors in measurement, andperiodic tableIn the future, there will also be newly discovered elements to fill in the blanks.He also predicted the characteristics of some unknown elements;Three of them were called eka silicon (classsilicon）、eka boron（Boron like）And eka aluminum（Aluminoid）These three new elements were discovered when he was alive, that is what we now call germanium, scandium and gallium.So in 1889, he could say in his speech in memory of Faraday: 'The periodic law enabled us to detect various undiscovered elements with unprecedented chemical foresight for the first time, and we could clearly see their various characteristics long before the discovery of new elements'.Mendeleev's periodic table is more complete than anyone's before, and has more solid evidence. "([US] M · E · Wex wrote:《Discovery of chemical elements》, Commercial Press, pp. 309-310)
Thus, Mendeleev'sPeriodic law of elementsHypothesis is a product that is based on empirical facts and is not restricted by the original facts.A hypothesis should give a satisfactory explanation to the relevant facts as far as possible, and make a strong defense for the basic theoretical viewpoints of the hypothesis.But this does not mean that all relevant facts can be satisfactorily explained.Not to mention that if some relevant facts cannot be explained, you must give up your own assumptions.
As I have been wondering before, hypothesis can bring forward what an extraordinary conclusion it seems at that time, but it must contain conclusions that can be tested in practice, especially the inference about unknown facts.Otherwise, it will not be a scientific hypothesis, but a mythical empty talk.For example,Continental drift theoryAlthough the conjecture about the history of paleogeology describes something that has happened before human history, it contains conclusions that can be tested in practice, and it has inferred the location of unknown deposits.As fromWest AfricafinddiamondIt can be inferred that the same deposit can be found in the southeast of South America, that is, in the area that is supposed to be originally combined with West AfricaDiamond deposit。This is a conclusion that can be tested in practice.This is indeed the case.Nowadays, the theory of continental drift is very meaningful for prospecting work;Another exampleDarwinOftheory of evolutionIt is believed that human beings areAnthropoid apeEvolutionary, this is also a description of what has happened in human history, and it will never happen again, but evolution has inferred that there are ape remains in the stratum, which can be tested in practice.In 1881, Dupuya, a Dutch doctor, was reallyJavaA pair of anthropoid apes is found in the stratum ofskullThe fossils of thigh bone, thigh bone and several teeth confirm Darwin's inference about ape remains.
Naturally, due to the historical limitations of practical activities, some theories were testable, but difficult to realize at that time.Their test will be completed in the process of history.It is recognized that the question of whether it can be inspected should be distinguished from the question of whether the inspection conditions are available.That is to say, it is unreasonable to put forward a hypothesis that is not testable. It is reasonable to put forward a hypothesis that is testable but does not have the conditions for testing.
Simple structure and rigorous surface
The complexity of the content of the hypothesis and the way of its formation depend first on the objective nature of the research object, and also closely related to the theoretical systematization of the researchers.When forming a hypothesis, the process from the initial stage to the completion stage is a process of constantly expanding the content, which is often mixed with a lot of irrelevant or redundant content, and it may also occur that the various parts and their different aspects are not very coordinated.Therefore, we should pay attention to the content of cleaning and refining hypothesis to make it concise.Attention should also be paid to the coordination between the whole and the parts, between the parts, and between the sides to make it rigorous.
The best way to make the theoretical viewpoint of hypothesis concise and rigorous is to establish an axiomatic deduction system.This is to choose a few of the most basic theoretical propositions as axioms or axioms, which are the highest and most common theoretical propositions.Other propositions with lower universality are deduced from them layer by layer.But the axiomatic deduction system is not the starting point of cognition, but the systematic summary of the past richTheoretical knowledgeResults.It can only be established on the basis of a certain abundance of knowledge.Therefore, it is conditional to establish the deductive system of axioms.
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Ways and means
In the form of hypothesis, people often put forward interpretative theories with opposite views.Which theory is the truth?This does not depend on individual beliefs or group recognition, nor does it depend on whether it can be used as a convenient means or tool, but whether it conforms to objective reality.That is to say, after the hypothesis is formed, subjective knowledge must also be reflected inobjective reality , tested by human social practice.
First, draw conclusions about facts from the basic theoretical perspective of hypothesis (monosyllabicObservation statement）。This is the deductive process of hypothesis testing.It should be understood here that it is not enough to deduce the statement of facts if only the basic theoretical viewpoint of hypothesis is taken as the premise.For example, only "allTyphoid diseasePatients are long-termhave a high fever”As a prerequisite, it cannot be deduced that "Zhang San will have a high fever for a long time", but it must also have the premise of stating the antecedents: "Zhang San is a typhoid patient", and in order to diagnose "Zhang San is a typhoid patient", it must also use otherPathologyKnowledge.It can be seen that the deduction process of hypothesis testing must combine the background knowledge and introduce the statement of antecedents and other laws and principles into the premise.The conclusion about the fact, which is derived from the basic theory of hypothesis and other knowledge, may be a statement about known facts, or a statement about unknown facts.If what the hypothesis test deduces is a statement of known facts, then this is the interpretation of known facts.If the hypothesis test deduces a statement about unknown facts, then this is the prediction of unknown facts.It must be clear that the explanation of known facts is just a "general test" of hypothesis theory, while the prediction of unknown facts is a "strict test" of hypothesis theory.The latter is more important than the former.In order to apply the basic theory of hypothesis to explain more complex known facts or predict unknown facts, it is usually necessary to make an auxiliary hypothesis.For example, in 1834, German astronomer Besselprecision measurement The location of stars and the sorting of previous observation data, found thatSiriusThe position of is periodicDeviation degree, swinging from left to right.Why is this?Purcell applicationLaw of universal gravitationIn 1844, we speculated that Sirius had a weak luminosity and a large masscompanionThey both move around a common gravitational center.Because of the gravity of the companion star, the position of Sirius has a periodic swing phenomenon.The above applicationLaw of universal gravitationTo explain the periodic wobble of Sirius' position and predict that Sirius has a companion star is an auxiliary hypothesis that can test the law of gravity.Another example is that between 1844-1845, Adams in England and FranceLeverrier Applying the law of universal gravitationUranusOrbitalPerturbationTo predict the unknownNeptuneThis is also an auxiliary hypothesis that can test the law of universal gravitation.When the deductive process of hypothesis testing is completed, then people passPractical testA factual conclusion derived from the basic theoretical point of view of a hypothesis.This is a process of fact verification.The verification process of facts can be either directly verified by experience or indirectly verified by experience.For example, according to the hypothesis that the earth inhabited by human beings is spherical, the following conclusion must be drawn: when people start from a certain place and travel in the same direction, they will always return to the original place of departure.To check whether this conclusion is true, people can find it out directly from experience as long as they take a world trip.Human historyMagellan and his companions completed this activity for the first time last time.However, not all the verification processes of facts can adopt the direct verification of experience, and sometimes people have to adopt the indirect verification of experience.For example, from“Continental drift theory”Developed“Seafloor spreading theory”It is believed that the convection material under the crust（Magma）Constantly fromHailing(in the middle of the oceanUndersea mountain range）The new sea bottom is generated by gushing out, and then gradually expands (displaces) from both sides of the ridge after the formation of the new sea bottom.In this way, the sea floor is like a conveyor belt from the central ridge tooceanic trench(The deepest part of the ocean at the junction of the ocean and the continental block) moves, and after it reaches the trench, it subducts downward, falling back to the depth inside the crust.According to this assumption, the following conclusions can be drawn: the sea floor closer to the central ridge is younger, and the sea floor farther away from the central ridge is older.Because of the underseaMovement speedEvery year, it is about several centimeters. Therefore, the seafloor material gushes out from the central ridge, then moves to the trench and falls back into the crust. The whole process takes about 200 million to 300 million years.To check these statements about the age of the seabed, it is impossible to directly confirm them by experience.Because the history of mankind so far is just a moment in the history of earth evolution.However, people can use the traceRadioactive elementAccording to the decay period and quantity of radioactive elements, the age of rock stratum can be calculated.asNatural uraniumIt can be split into lead, and the age of the rock stratum can be calculated by measuring the amount of uranium and lead in the rock stratum.The rock ages of the islands in the ocean are measured by this method. The results show that the closer the islands are to the central ridge, the younger they are, and the farther they are from the central ridge, the older they are.Therefore,Seafloor spreading theoryThe prediction of new and old submarine distribution has been indirectly confirmed by experience.
Real bid process
The above is a general summary of the ways and means of hypothesis testing.Right nowTest hypothesisThe actual bidding process of.In general, the test of hypothesis theory began as early as the formation of hypothesis, while the strict test of hypothesis theory is later than the formation of hypothesis.
Why do people begin to make a general test of the theoretical viewpoints of hypotheses in the process of their formation?firstIn the initial stage of hypothesis formation, researchers' initial assumptions are tentative and diversified.After repeated investigation, people choose the best one and choose a guess that can give a more complete explanation of many facts.That is to say, the initial hypothetical selection process is accompanied by a general test.secondlyIn the completion stage of hypothesis formation, researchers must make extensive defense for the selected theoretical viewpoints, systematically and comprehensively explain the known relevant facts, and seek the support of empirical evidence.This is a further general test of the theoretical viewpoints of the hypothesis.
As has been said before, explaining the "abundance" of known facts is just a general test of the theoretical viewpoint of hypothesis, which does not have the most important significance.Only by predicting unknown facts can the theoretical viewpoint of hypothesis be strictly tested.So, what kind of facts can defend the theoretical view of hypothesis?How much support can they give to theoretical viewpoints?It should be noted here that,The known facts related to hypothesis can be divided into two categories: one is the known facts that were investigated and quoted when a preliminary hypothesis was formed。They are pre selected and arranged by researchers, who have deliberately conceived a theoretical point of view in order to explain these facts.This kind of facts can only give "false support" to the theoretical point of view, and can not give real support;Another kind of known facts has not been examined and quoted when making preliminary assumptions。The reason why they are regarded as facts related to a certain theoretical point of view is that they were recognized through deduction after the formation of a certain theoretical point of view.Such facts can give general strength support to theoretical views.Secondly, some relevant facts were newly discovered after the formation of theoretical views, but they were discovered not according to the prediction of this theory, but because of another kind of research work.Only after they were discovered, people realized that they were related to this theoretical view through inference.This kind of fact more obviously supports the general strength of the theoretical view.for instance:
"Two astronomers from Bell Telephone Laboratory in the United States, Penchais and Wilson, tested theirradio telescopeI want to explore what the interference background noise is?Since radio signals come from all directions of the sky evenly, this proves that they do not come from ground sources.Through research, it turns out thatBlackbody radiationThe temperature of its source is only about 3K.Along with the progress of this research,Princeton University Dick and his colleaguesBell Telephone Laboratory30 miles) is independently studying thePrimitive fireballHow did the energy of the Big Bang happen.They concluded that although the initial temperature of the explosion may be 1010K and the wavelength of radiation is very short, the temperature will cool down due to expansion.According to their theory, they predicted that the temperature after cooling would be about 5K, which was close to the temperature that caused cosmic noise radiation found by Penchais and Wilson in the Bell telephone real face room.More in-depth research has found that the observed radiation may indeed be left behind by the initial explosion of the universe.This kind of radiation has been in the universe for a long time and has lost energy continuously. Today, its temperature is no longer 1010K, but 3K.Radiation of this nature is very beneficialBig Bang Theory, because it isSteady state theoryChina does not work at all.(S.J. Inglis, Planets, Stars and Galaxies,Science Press, pp. 473-474)
The newly discovered facts after the formation of theoretical viewpoints, in addition to those discovered by other research work that can be explained by this theoretical viewpoint, are discovered by applying this theoretical viewpoint to make predictions.The latter kind of facts can give strong support to the theory.For example, according to Einstein'sGeneral relativity, light ingravitational fieldThe middle must be curved.He predicted that the starlightsunlightIt will deflect when passing near the surface.Because the starlight near the sun can onlyTotal solar eclipseThis conclusion was first tested by a British expedition in Africa in 1919 when observing a total solar eclipse.The observation of the total solar eclipse in 1919 and other observations since then have confirmed thatLight deflectionThe prophecy of.Although Einstein's prediction was successful in qualitative verification, it was not ideal in quantitative verification,ObservationsIt is higher than the predicted value.U.S.APrinceton University Dick of-tensorTheory gives explanation.We can say that the fact that the star deflection was observed during the total solar eclipse in 1919 is that EinsteinGeneral relativityIt was predicted by Dick laterScalar tensor theoryCan explain.However, its support for Einstein's general relativity will exceed that for Dick's scalar tensor theory.
As mentioned above, the theoretical viewpoint of the hypothesis is strictly tested by examining its prediction in practice.If its prediction is successful in practice, it will be confirmed to a certain extent.Although the success of prediction cannot fully confirm the theoryAfterpartFrom (prediction) to positive antecedent (theory), such reasoning does not haveInevitabilityOf.However, the success of prediction has provided strong support for the theory.It is a main criterion for people to evaluate and choose different theories.
On the contrary, if the theoretical prediction fails in the practical verification, it does not mean that the theory has been falsified.Although such reasoning is inevitable from negating the latter to negating the former.However, theoretical predictions are not simply derived from the basic theoretical point of view of hypothesis.It is usually obtained by applying the basic theory of hypothesis and combining background knowledge to establish auxiliary hypothesis.Therefore, the failure of prediction can be solved by changing the auxiliary hypothesis. The key is to see whether the prediction derived from the new auxiliary hypothesis can be verified.
In order to solve a series of difficult problems that have emerged one after another, researchers will constantly make new auxiliary hypotheses by applying the basic theoretical viewpoints and background knowledge of hypothesis, which is not only to constantly make new predictions about unknown facts, but also to modify and develop the content of the original hypothesis.If new predictions are more and more confirmed, it means that the revision and development of the hypothesis content are closer and closer to the objective realityVerisimilitudeThe degree is getting higher and higher.Therefore, it is closely related to thecompetitive powerIs growing.On the contrary, if new predictions cannot be verified, or are verified less and less, then their competitiveness against opposing hypotheses is declining, and they are more likely to be eliminated.
To sum up, the final result of hypothesis testing is to form a picture of the competition between opposite hypotheses and the historical replacement.
General guidelines
Now, we further discuss theGeneral guidelines。Generally speaking, people should pay attention to the following points when testing hypotheses:
（1） We should strive to make strict inspection, but we should not ignore the significance of general inspection
The successful interpretation of known facts is quite different from the successful prediction of unknown facts. The strength of support given by the latter to the theory is far greater than that of the former.Therefore, when testing the theoretical viewpoints of hypotheses, researchers should first concentrate on predicting the unknown facts.And the more bold and novel the prediction, the more severe the test of theory.If this bold and novel prediction is successful in practice, it will give extra strong support to the theory.However, researchers should not neglect to make a satisfactory explanation of the known facts.All relevant known facts that have not been quoted when constructing the theoretical viewpoints of hypothesis, whether discovered after the formation of the theoretical viewpoints or before the formation of the theoretical viewpoints, will serve as empirical evidence to support the theory and play a role in defending the theory as long as they can be satisfactorily explained.
（2） The auxiliary hypothesis should be improved to justify the theory, but no ad hoc hypothesis should be made
In the process of hypothesis testing, the failure of prediction is "abnormal".This does not mean that the basic theoretical view of the hypothesis has been falsified.Researchers can continue to defend the theory by improving the auxiliary assistant hypothesis.But the justification itself must be testable.For example, applicationLaw of universal gravitationAnd astronomical observation data, it is predicted that a comet will passPerihelionOnBless The Child 。If a comet returns to the sun but is not at the perihelion, then this "anomaly" cannot falsify the law of gravity, and people can use an auxiliary hypothesis to justify it.For example, Huili has sufferedsolar systemThe gravity of an unknown planet somewhere on the edge delayed the date of reaching the perihelion.This can be tested by astronomical observation.Therefore, it is permissible to establish such an auxiliary hypothesis to justify.However, if the above failure to predict the comet perihelion date is explained as a result of the "faraway cosmic visitors" using some technical means once mastered by humans to "tease", then this cannot be tested.We call this untested hypothesis, which is purposely established to protect a certain theoretical viewpoint, ad hoc hypothesis.The ad hoc assumption is unreasonable and should be avoided.
（3） The individual test of hypothesis should be regarded as relative, but it should not be denied as an indicator of the relative verisimilitude of hypothesis
For hypothesis theory, no matter whether there are successful and favorable results or failed and unfavorable results in individual testing activities, they cannot absolutely determine the truth of theoretical views.This means that there is no "decisive experiment" [so-called“Judgmental experiment”It refers to the contradictory proposition about the fact derived from two competing hypotheses H1 and H2, namely, "if H1, then e";"If H2, then not e".Then, arrange an experiment to check the fact e. Some people think that this can refute one hypothesis and support the other.If the experimental result is positive e, then H1 can be confirmed and H2 can be refuted;If the experimental result is negative e, then H1 can be refuted and H2 can be confirmed.Through such an experiment, one can make a choice between the two hypotheses and decide whether to accept or reject them, so it is called "decisive experiment"].History of ScienceThe "decisive experiment" mentioned above does not have the meaning of "final judgment".
Any inspection activity is not absolutely accurate and strict, and can be understood differently.For example: chemists in the 17th centuryBoyle, used such experiments to "prove"Phlogiston theory。He heated the metal in the container. After measurement, the weight of the heated metal increased.It seems that this means that when the metal is heated“Phlogiston”It goes through the container into the metal, so the weight of the metal increases.Boyle did not estimate that part of the gas in the bottle was combined with the hot metal, but opened itCorkThe outside air is replenished.Until the 18th century, chemists such as Lavoisier and Romonosov verified Boyle's experiment again. They sealed the container put into the metal, heated it, and weighed it without opening the cork.It was found that the weight did not change, and there was no "phlogiston" drilling bottle to combine with metal.
For individual inspection activitiesRelativityAlso, the concrete practice of human beings is always incomplete, with historical limitations.It is often the case in the history of science that although the theoretical content of a hypothesis contains part of the truth, due to the limitations of the technical level of that era, part of the truth contained in the theory could not be confirmed.On the contrary, it was once "judged" as fallacy.For example, regarding the view that one chemical element can be transformed into another, previous chemists, in view of the long-term failure experience of medieval alchemists, considered this to be a fallacious and ridiculous idea.However, contemporary nuclearphysical experiment But it highly confirms the view that one chemical element can be transformed into another.
It can be seen that individual inspection activities do not have the meaning of absolute judgment.However, this does not mean that individual inspection activities are meaningless.Cognition is a process of development. Scientific theory is only an approximate description of the objective reality, which only has a certain degree of verisimilitude. To evaluate the verisimilitude of a theory, it is impossible to use an abstract formula that subtracts its false content from its true content.It is impossible to make an absolute assessment of the fidelity of a theory.People can only evaluate the relative fidelity of a theory, and its indicators are composed of the records of individual inspection activities so far.
In short, the testing of hypotheses is a historical development.Any individual individual testing activity is not enough to determine the truth of the theory.They can only be used as a reference for evaluating the relative fidelity index of theory.
（4） We should reject the competing hypothesis, but we should not ignore the reasonable evaluation of the competing hypothesis
Since people can put forward different theoretical viewpoints to answer the same question, this also forms the competition of different hypotheses.Researchers need not only to defend their own theories, but also to refute the competing theories.To refute the theory competing with it is to defend one's own theory indirectly.If the researchers have no ability to challenge the theory of competition or face the attack from the theory of competition, they will be eliminated or temporarily eliminated because their own theory has lost the ability to compete and is facing a serious crisis.A growing theory with competitiveness can not only continuously "digest" its own "counterexamples", but also constantly provide "counterexamples" of competing theories to reject competing hypotheses.
Because the completion of hypothesis testing is a historical process.No matter what period the competition hypothesis is evaluated, it is bound to have a relativeTime index。"We can only know under the conditions of our times, and we will know to what extent these conditions reach."（《Selected Works of Marx and Engels》Volume 3,People's Publishing House, p. 562).On the one hand, hypotheses that affirm competition with each other can be reasonably evaluated after certain tests.On the other hand, it is affirmed that this reasonable evaluation is historical and relative.It will become increasingly complete with the further development of practical testing activities.
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Fantasy is a poet's wing,hypothesisIt is the ladder of science——Goethe
sciencehypothesisIt played a leading and linking role in the formation of scientific theories——Zhou Haizhong
Scientists must have imagination, so that they can imagine how things that cannot be observed by the naked eye happen and function, and conceivehypothesis。——Beveridge
