CAT Critical Reasoning Practice question with Solution 84

According to the definition, there are two requirements for a scientific theory to be “good.” It must be able to describe a broad set of events using only a few elements, and it must make clear predictions concerning future events. Aristotle’s cosmological theory, which claimed that everything was made out of four elements, but failed to make any definite predictions, satisfied the first requirement but failed the second. For this reason, the author concludes that Aristotle’s cosmological theory was not a good one. All the choices may be inferred from the passage except (B). We don’t know anything about the “major concerns” of Aristotle’s theory or whether “the observation of physical phenomena” is one of those concerns. (B) shifts the scope of the argument and cannot be inferred.

(A) simply paraphrases the stimulus’s second condition for a good scientific theory, that it must make definite predictions about the results of future observations. So if the stimulus statements are true, (A) necessarily follows.

(C) The author said that Aristotle’s theory (which was based on four elements) fulfilled the first requirement of a good scientific theory, the simplicity requirement; therefore, a theory based on four elements must be able to fulfil the simplicity requirement.

(D) The stimulus requires that a good scientific theory must account for many observations with a model that contains few elements, so a theory that contains many elements doesn’t make the grade.

(E) is essentially a restatement of the author’s evaluation of Aristotle’s cosmological theory; the author said it satisfied the first requirement (describing a large class of observations), by accounting for everything in terms of four elements.