Distinguish between "Infer" and "Guess"
In everyday conversation, people often use the word "infer" as a fancy synonym for "guess". However the two are different. The word "infer" means that you know for sure based on the information provided, but the author did not explicitly state that information. Consider a conditional logic example:
| If A g B | |
| If B g C |
From this information, we may infer that If A g C.
Now, look at a guess:
| If A g B | |
| If B g C | |
| _______ | |
| Guess: | If A g D |
Can we infer (must be true) If A g D ? Definitely not, as the information provided does not mention D. Thus, the above shows a guess.
This guess is built on the assumption: If C g D.
| Premise | If A g B |
| Premise | If B g C |
| Assumption: | If C g D |
| Guess: | If A g D |
When you encounter questions that use language such as "properly concluded", "properly inferred", or "must be true", seek to distinguish between the incorrect answer choices that often could be true (yet could be false), and the correct answer choice, which must be true (cannot be false). For good examples of inference questions that contains four answer choices that are guesses, rather than inferences, and one choice that must be true, see LSAT PrepTest 48, Section 4, Question 14, LSAT PrepTest 49, Section 4, Question 3, or LSAT PrepTest 50 Section 2, Question 9. Knowing the definition of "infer" can help you with other types of questions as well. See (A) on LSAT PrepTest 50, Section 2, Question 4.