LSAT Explanation PT 44, S2, Q1: The tidal range at a particular

LSAT Question Stem

Which one of the following most accurately describes a flaw in the reasoning above? 

Logical Reasoning Question Type

This is a Flaw question. 

Correct Answer

The correct answer to this question is B. 

LSAT Question Complete Explanation

First, let's analyze the argument in the passage. The argument can be broken down as follows:

Premise: The only forces involved in causing tides are the sun's and moon's gravity.

Conclusion: The magnitudes of tidal ranges must be explained entirely by gravitational forces.

The question type for this problem is Flaw, and it asks us to identify a flaw in the reasoning of the argument.

To better understand the passage, let's use a simple example. Imagine a ball being pulled by two magnets, one representing the sun's gravity and the other the moon's gravity. The ball moves due to the pull of both magnets, but the distance it moves (analogous to the tidal range) could also be affected by other factors, such as the surface it's on or the strength of the magnets.

An "Evaluate" question for this argument could be: "Are there any other factors that could affect the size of a tidal range besides gravitational forces?"

Now, let's discuss the answer choices:

a) The passage gives only one example of a tidal range, but this is not a flaw in the reasoning. The example is used to illustrate how big tidal ranges can get, and more examples are not necessarily required in this context.

b) This is the correct answer choice. It points out the author's failure to consider other conditions (alternative causes) that might affect the size of a tidal range, such as the shape of the coastline or the depth of the ocean.

c) The passage does not discuss the measurement of tides, so this choice does not describe a flaw in the reasoning.

d) The author does not discuss most activity in the world's oceans, only tides and tidal ranges. This choice is not relevant to the argument and is incorrect.

e) The argument concludes that gravitational forces account for the magnitude of tidal ranges, so it is not important to differentiate between the tidal effects of the moon's gravity and those of the sun's. This choice does not describe a flaw in the reasoning.