Answer fifteen questions, selecting any three from each Unit. (15 x 1 = 15 Marks)
1. Is logic a science or an art or both?
Logic is considered both a science (a systematic study of valid reasoning) and an art (the practical application of those principles)
.2. "Logic is the study of the methods and principles used to distinguish correct (good) from incorrect (bad) reasoning." Who says this?
This definition is famously provided by Irving M. Copi
.3. What kind of science logic is?
Logic is a normative science because it sets the norms or standards for correct thinking
.5. What kind of opposition exists between A and O proposition?
The opposition between A (Universal Affirmative) and O (Particular Negative) is Contradictory
.6. What is proposition?
A proposition is a declarative sentence that is either true or false
.7. "Universal propositions have existential import." Is it true?
In traditional logic, yes; however, in Boolean logic, universal propositions do not have existential import
.9. How many propositions are there in an immediate inference?
There are two propositions: one premise and one conclusion
.11. Can O proposition be converted?
No, an O proposition cannot be validly converted
.12. "Quality is changed in conversion." Is it true?
False. In conversion, the quality of the proposition must remain the same.
13. Name one valid mood of second figure.
Cesare (or Camestres, Festino, Baroco) is a valid mood of the second figure
.14. What is the position of middle term in the 1st figure?
In the 1st figure, the middle term is the subject of the major premise and the predicate of the minor premise
.15. State any one rule of syllogism.
A valid categorical syllogism must contain exactly three terms, each used in the same sense throughout the argument
.18. Give symbolic representation of the following statement: "A is the subset of B."
The symbolic representation is: A ⊆ B
.19. What is the name of the symbol '∈'?
The symbol denotes "Element of" or "Membership" in a set
.20. If the set A = human beings, set B = rational animals, is A equal to B?
Yes, A = B, as they refer to the same class of beings in classical logic
.Answer five questions, selecting one from each Unit. (5 x 2 = 10 Marks)
21. What is the law of contradiction?
The law of contradiction states that no statement can be both true and false at the same time in the same respect. Symbolically: ~(p · ~p).
23. What is existential import?
Existential import is the implication that the objects referred to by the subject term of a proposition actually exist
.26. What is simple conversion and conversion by limitation?
Simple Conversion: The subject and predicate are interchanged without changing quantity (valid for E and I).
Conversion by Limitation: The quantity is changed from universal to particular during interchange (valid for A becoming I).
27. What is figure of syllogism?
Figure refers to the logical shape of a syllogism determined by the position of the middle term in the premises
.29. What is null set (empty set)?
A null set is a set that contains no elements, symbolized by ∅ or { }
.Answer five questions, selecting one from each Unit. (5 x 5 = 25 Marks)
32. Write a short note on 'truth and validity'.
Truth refers to the correspondence of a proposition with reality; it applies to individual statements
. Validity refers to the logical necessity between premises and conclusion; it applies only to arguments. A valid argument may have false premises, but if the premises are true and the argument is valid, it is called a "sound" argument.34. Explain briefly traditional square of opposition.
The traditional square of opposition illustrates the logical relationships between the four categorical propositions (A, E, I, O)
:36. Reduce the following sentence into logical form and then convert, obvert and contrapose: "Mothers are always kindhearted."
38. Use Venn diagram technique to test the validity or invalidity: Some reformers are fanatics. All reformers are idealists. Therefore, some idealists are fanatics.
Logical Form:
Analysis: In the Venn diagram, when we shade 'All R is I' and mark an 'X' for 'Some R is F', the 'X' necessarily falls inside the intersection of I and F. Thus, the conclusion "Some I is F" is already contained in the diagram of the premises. The argument is Valid.
40. Explain with examples union of sets and intersection of set.
Union (A ∪ B): The set of all elements belonging to A, or B, or both. Example: If A={1,2} and B={2,3}, then A ∪ B = {1,2,3}.
Intersection (A ∩ B): The set of elements belonging to both A and B. Example: If A={1,2} and B={2,3}, then A ∩ B = {2}.