If the proposition 'some fishes are not amphibians' is given as false then which of the following propositions can be immediately inferred to be true?

A. No amphibians are fishes.

B. All fishes are amphibians.

C. No fishes are amphibians.

D. Some fishes are amphibians.

Choose the most appropriate answer from the options given below:

Question

Question

This question was previously asked in

UGC NET Official Paper-I (Held On: 05 Mar, 2023 Shift 1)

Answer 1

In syllogism, a proposition is a statement that asserts or denies something about a subject, and it is used to form a logical argument.

Key Points

The given proposition "some fishes are not amphibians" is false, which means that all fishes are amphibians.
This is because if there is at least one fish that is not an amphibian, then the proposition "some fishes are not amphibians" would be true.
Based on this, we can infer that the proposition "All fishes are amphibians" (option B) is true, since it is the opposite of the original false proposition.
We can also infer that the proposition "Some fishes are amphibians" (option D) is true, since we have established that all fishes are amphibians, so there must be at least some fishes that are amphibians.

Therefore, options B and D are the correct answers.