Class 12 Logic & Philosophy Chapter 4 Mill’s Method of Experimental Enquiry
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Selected Questions & Answers
A. Very Short Answer Questions: (Marks for each – 1)
1. How many stages are there in a hypothesis?
Ans: Four.
2. Is the Method of Residues deductive?
Ans: No.
3. How many instances are required for the Method of Difference?
Ans: Two.
4. Is the Method of Difference a method of discovery or of proof?
Ans: Of proof.
5. What is the main defect that renders the Method of Agreementineffective?
Ans: The possibility of plurality of causes.
6. How many instances are necessary for applying the Joint Methodof Agreement and Difference?
Ans: Two.
7. In which special field does the Method of Concomitant Variationsbecome indispensable?
Ans: In cases of quantitative increase and decrease.
8. “The Method of Concomitant Variations is especially applicablein cases of permanence.” Is the statement true?
Ans: True.
9. Is the Method of Concomitant Variations observational or experimental?
Ans: Both.
10. When the Method of Difference is applied as an observational method, by what defect is it vitiated?
Ans: The defect of plurality of causes.
11. “When temperature increases, the mercury in the thermometerrises; when temperature decreases, the mercury falls. Therefore, increase or decrease of temperature is the cause of the rise or fall of mercury.” This example belongs to which experimental method?
Ans: The Method of Concomitant Variations.
12. Give one example of the Method of Residues.
Ans: The weight of a gallon filled with petroleum is 30 kg. We know that the petroleum in it weighs 25 kg. Therefore, by applying the Method ofResidues, it is concluded that the weight of the empty gallon is 5 kg.
13. State the canon of the Method of Concomitant Variations.
Ans: If any kind of change in one phenomenon is accompanied by aparticular kind of change in another phenomenon, then the first phenomenonis the cause or effect of the second, or they are causally connected in someway.
14. Define the Method of Residues.
Ans: If a part of a phenomenon is known from previous induction to bethe effect of a certain antecedent, then after subtracting that part from thewhole phenomenon, the remaining part is the effect of the remainingantecedent.
15. The subject-matter of a hypothesis must be a real or ______cause. (Fill in the blank)
Ans: Existing cause.
16. “Electricity is a kind of fluid.” This is an example of which typeof hypothesis?
Ans: Working hypothesis.
17. According to which thinker are hypotheses of three kinds?
Ans: According to Stebbing.
18. Is the power of prediction a condition of a valid hypothesis?
Ans: Yes.
19. What is meant by an existing cause?
Ans: An existing cause means a cause whose existence is logicallyadmissible and whose acceptance does not involve self-contradiction.
20. “A hypothesis is always a preliminary assumption.” Is thestatement true?
Ans: True.
21. ”A hypothesis is a tentative assumption.” Is the statement true? H. S. ’14
Ans: Yes.
22. According to Mill’s definition of hypothesis, what is the laststage of hypothesis? H. S. ’15
Ans: Verification.
23. What is meant by the condition of verifiability of a validhypothesis? H. S. ’15
Ans: The condition of verifiability of a valid hypothesis means that thehypothesis must be capable of being proved either true or false.
24. What is a crucial or decisive instance? H. S. ’16
Ans: Those instances which satisfactorily and conclusively explain aphenomenon are called crucial or decisive instances.
25. Is hypothesis a process of problem-solving?
Ans: Yes.
26. “Hypothesis is a skillful activity and the first stage of discovery.”Do you agree?
Ans: Yes.
27. Which of the following statements is true? H. S. ’15
(a) Experiment is the discovery of events and observation is the creationof events.
(b) Observation comes after experiment.
(c) In experiment, we cannot infer cause from effect.
Ans: (c) In experiment, we cannot infer cause from effect.
28. Which of the following statements is not correct? H. S. ’16
(a) Only by observation can a hypothesis be directly verified.
(b) A hypothesis can be directly verified either by observation or byexperiment.
(c) Only by experiment can a hypothesis be directly verified.
Ans: (b) A hypothesis can be directly verified either by observation or byexperiment.
29. What is meant by an existing cause?
Ans: Real cause.
30. Is verification necessary for a hypothesis?
Ans: Yes.
31. By what type of hypothesis was the planet Neptune discovered? H. S. ’20
Ans: Explanatory hypothesis.
32. According to Mill’s definition of hypothesis, what is the firststage of hypothesis? H. S. ’19
Ans: Observation of natural phenomena.
B. Short Questions and Answers: (Marks for each–2)
1. What is meant by a Working Hypothesis? H. S. ’15, ’18
Ans: A temporary hypothesis formed for the purpose of explaining aphenomenon, in the absence of proper means of observation and based onlimited data obtained from observation, is called a Working Hypothesis.
2. “Observation is the first stage of hypothesis.” Why?
Ans: Observation is the first stage of hypothesis because throughobservation we become acquainted with natural phenomena. Thisacquaintance gives rise to questions in our mind regarding those phenomena, and we feel the necessity of inquiry in order to find answers or solutions. Therefore, observation is the first stage of hypothesis.
3. “A hypothesis cannot contradict established truths.” Why?
Ans: A hypothesis cannot contradict established truths because if a newlyformed hypothesis is not consistent with previously acquired knowledge, that is, if it is contradictory or inconsistent, then doubt will arise in our mindregarding its truth.
4. Write the definition of hypothesis given by John Stuart Mill.
Ans: The logician John Stuart Mill defines hypothesis as follows: “Ahypothesis is a supposition made without sufficient evidence, in order to drawconclusions in accordance with real facts; and if it is found that the conclusionsagree with known truths, then the supposition may be regarded as true orprobably true.”
5. What is meant by Circumstantial Hypothesis? H. S. ’13
Ans: When the agent of a phenomenon or the law according to which it occurred is known, but the circumstances under which it occurred areunknown, the hypothesis formed to know the surrounding conditions is calleda Circumstantial Hypothesis.
6. Briefly explain any one condition of a valid hypothesis with asuitable example. H. S. ’16
Ans: One condition of a valid hypothesis is that its subject-matter must be an existing cause. By existing cause we mean a cause whose existence islogically acceptable. For example, if a child goes missing and it is assumedthat a sky-god has taken the child away, this cannot be a valid hypothesisbecause such a cause is not an existing one.
7. How many kinds of verification of hypothesis are there and whatare they? H. S. ’20
Ans: There are two kinds of verification of hypothesis:
(a) Direct and (b) Indirect.
8. Give an example of a Law-related Hypothesis. H. S. ’19
Ans: When the agent of a phenomenon and the circumstances of itsoccurrence are known, but the law according to which it occurred is unknown, the hypothesis formed to determine that law is called a Law-related Hypothesis. For example, suppose a robbery takes place in a house and the robber is known, but the rule or method according to which the robbery was committed isunknown; the hypothesis formed to determine that rule is a Law-related Hypothesis.
C. Medium Length Questions & Answers (Marks for each–4)1. Discuss the different kinds of hypothesis according to purpose.
Or
Discuss the classification of hypothesis according to Stebbing. H. S. ’20
Ans: A hypothesis is a preliminary assumption adopted to explain aphenomenon scientifically for the purpose of obtaining clear knowledge about it. According to purpose, hypothesis is of three kinds: ExplanatoryHypothesis, Descriptive Hypothesis, and Analogical Hypothesis. These arebriefly discussed below.
(1) Explanatory Hypothesis: The hypothesis which assumes an agent orcause and tries to explain a phenomenon with its help is called an ExplanatoryHypothesis.
(2) Descriptive Hypothesis: The hypothesis which assumes a law and triesto describe how a phenomenon has occurred according to that law is called aDescriptive Hypothesis.
(3) Analogical Hypothesis: An Analogical Hypothesis is one in which it isassumed that what is true in one class may also be true in another class, provided that both classes share certain specific common and structural characteristics. The hypothesis formed to establish such similarity is calledan Analogical Hypothesis.
2. Mention four necessities of hypothesis. H. S. ’14, ’16
Ans: To prove the truth or falsity of a phenomenon, experiment andobservation are necessary, and for that a definite hypothesis is required. Thenecessities of hypothesis are as follows:
(1) Hypothesis is the preliminary stage of all scientific inquiry. All wellestablished scientific laws and principles begin as hypotheses.
(2) Hypothesis makes observation and experiment possible.
(3) Hypothesis also helps in deduction. The general premises required forestablishing deductive conclusions can be obtained through hypothesis.
(4) Hypothesis is necessary and used in daily life as well. Where experiment is not possible and observation yields only probability, hypothesis becomesthe only means of explaining a phenomenon.
3. Write the differences between Explanatory Hypothesis andDescriptive Hypothesis. H. S. ’15
Ans: Explanatory Hypothesis and Descriptive Hypothesis are two typesclassified according to purpose. The differences between them are as follows: An Explanatory Hypothesis assumes an agent or cause and attempts to explain a phenomenon with its help.
On the other hand, a Descriptive Hypothesis assumes a law and attemptsto describe how a phenomenon has occurred according to that law. An Explanatory Hypothesis investigates the cause of an event and tries toexplain it.
In contrast, a Descriptive Hypothesis describes the mode of operation ofthat cause, that is, the rule according to which the agent performed the action. An Explanatory Hypothesis is considered stronger, as it seeks to explainone event by means of another event.
A Descriptive Hypothesis is generally used to determine the systematicrelation among complex phenomena.
4. With suitable examples, distinguish between Agent-relatedHypothesis and Law-related Hypothesis. H. S. ’16
Ans: A hypothesis is a preliminary assumption adopted to give a scientificexplanation of a phenomenon. According to difference in explanation, hypothesis may be of three kinds: Agent-related Hypothesis, Law-relatedHypothesis, and Circumstantial Hypothesis.
(1) Agent-related Hypothesis: Sometimes it is known how an event occurred, but it is not known who caused it. In such cases, the hypothesisformed to identify the agent is called an Agent-related Hypothesis. Forexample, if a businessman is murdered by an unknown assailant, the hypothesisformed to discover the identity of the assailant is an Agent-related Hypothesis.
(2) Law-related Hypothesis: When the agent and circumstances of anevent are known, but the law according to which it occurred is unknown, thehypothesis formed to determine that law is called a Law-related Hypothesis. For example, if a robbery occurs in a house and the robber is known, but therule according to which he committed the robbery is unknown, the hypothesisformed to determine that rule is a Law-related Hypothesis.
5. Write a short note on Working Hypothesis. H. S. ’13
Or
Define Working Hypothesis. H. S. ’20
Ans: A Working Hypothesis is a temporary hypothesis formed forexplaining a phenomenon in the absence of proper means of observation andon the basis of limited data.
Example: A weak student suddenly performs well in an examination.
The characteristics of a Working Hypothesis are:
(a) There is a lack of proper means of observation.
(b) It is based on limited data.
(c) It is temporary in nature.
6. What is hypothesis? Explain its nature. H. S. ’20
Ans: A hypothesis is a preliminary assumption adopted to explain aphenomenon scientifically for the purpose of obtaining clear knowledge about it.
The nature of hypothesis is as follows:
(a) A hypothesis is a tentative assumption.
(b) There is a lack of sufficient proof in support of it.
(c) From the assumption, conclusions are drawn in accordance with knownfacts.
(d) If the conclusions agree with known facts, the assumption is likely tobe true.
7. What is Observation? Discuss its characteristics. H. S. ’20
Ans: Observation is the systematic perception of a natural phenomenonin its natural environment with a definite purpose in view.
The characteristics of observation are:
(a) It always has a definite purpose.
(b) It is conducted in a natural environment.
(c) Since it takes place in a natural environment, the phenomenon observedis not under human control.
8. Write two differences between Observation and Experiment. H. S. ’20
Ans: Two differences between Observation and Experiment are:
(a) The scope of observation is wider than that of experiment.
(b) In observation, irrelevant factors cannot be eliminated; but inexperiment, they can be eliminated.
D. Essay-type Questions and Answers: (Marks for each–6)
1. Define Hypothesis. Discuss the conditions of a valid hypothesis. H. S. ’15, ’17, ’18
Or
Mention two conditions of a valid hypothesis. H. S. ’20
Ans: A hypothesis is a preliminary assumption adopted to explain aphenomenon scientifically for the purpose of obtaining clear knowledgeabout it. There are several conditions of a valid hypothesis, namely:
(a) Since a hypothesis is adopted to explain an idea or phenomenon, itsfirst condition is that it must be clear and definite. No inquiry can begin onthe basis of a vague assumption. Example: “There is heavy rainfall in America, so India is experiencing drought.” This assumption is not clear.
(b) A hypothesis must not contradict the laws of nature. Example: “A ghost gave an apple to a small boy.” This cannot be a valid hypothesis because it is contrary to the laws of nature.
(c) A hypothesis must be based on real facts or events. It must not beimaginary or fictitious. “In the fourth year of Ramen’s marriage, a daughterwill be born.” This cannot be regarded as a hypothesis.
(d) The subject-matter of a hypothesis must be an existing cause. Byexisting cause we mean a cause whose existence is logically acceptable. “Bazen performed well in the examination due to the blessing of a nakedfakir.” This is merely a baseless belief.
(e) A valid hypothesis must be simple and verifiable. An assumption that cannot be verified or is highly improbable cannot be a valid hypothesis. Copernicus said that the Earth revolves round the Sun. This is a validhypothesis because it can be verified.
2. Briefly explain the stages of hypothesis. H. S. ’14, ’16, ’17, ’18, ’19, ’20
Ans: A hypothesis is a preliminary assumption adopted to explain aphenomenon scientifically for the purpose of obtaining clear knowledge about it.
There are four stages of hypothesis, namely:
(1) The first stage is the observation of natural phenomena. Throughobservation we become acquainted with the subject to be explained. Thisacquaintance gives rise to questions in the mind and creates the necessity ofexplanation.
(2) The second stage is the formation of hypothesis. If from observationno definite proof of causal relation is obtained, causal connection cannot bedetermined with certainty. Still, on the basis of observation, a tentativeassumption is made to explain the phenomenon.
(3) The third stage is the deduction of conclusions from the tentativeassumption.
(4) The fourth stage is the verification of the deduced conclusions. At thisstage experiment and investigation begin. If after experiment the conclusionsagree with real facts, the assumption is likely to be true; if they do not agree, it is proved to be false.
3. Discuss the different kinds of hypothesis according to differencein explanation. H. S. ’18
Or
Explain the following kinds of hypothesis with examples:
(a) Agent-related Hypothesis, (b) Law-related Hypothesis, (c)Circumstantial Hypothesis.
Ans: A hypothesis is a preliminary assumption adopted to give a scientific explanation of a phenomenon. According to difference in explanation, hypothesis is of three kinds: Agent-related Hypothesis, Law-relatedHypothesis, and Circumstantial Hypothesis. These are briefly discussedbelow.
(1) Agent-related Hypothesis: Sometimes it is known how an event occurred, but it is not known who caused it. In such cases, the hypothesisformed to identify the agent is called an Agent-related Hypothesis. Forexample, if a businessman is murdered by an unknown assailant, the hypothesisformed to discover the identity of the assailant is an Agent-related Hypothesis.
(2) Law-related Hypothesis: When the agent of an event and thecircumstances of its occurrence are known, but the law according to which it occurred is unknown, the hypothesis formed to determine that law is called aLaw-related Hypothesis.
(3) Circumstantial Hypothesis: Any event or action occurs under varioussurrounding conditions. The set of conditions under which an event occurs iscalled its circumstances. When the agent and the law of an event are known, but the particular combination of surrounding conditions under which it occurred is unknown, the hypothesis formed to determine those surroundingconditions is called a Circumstantial Hypothesis.
