LSAT 117 | Section 2 | Logical Reasoning: Q1

LR Question 1 Explanation

QUESTION TEXT: The tidal range at a particular location …

QUESTION TYPE: Flawed Reasoning

CONCLUSION: The magnitude of tidal ranges is explained entirely by gravitational forces.

REASONING: They are the only forces that cause tides.

ANALYSIS: The evidence says gravitational forces are what causes tidal ranges to happen.

But then the argument concludes that gravitational forces are what determines how large the effects of tidal ranges are.

Gravity may be the only force that creates tides, but that does not mean gravity alone determines why some places have much larger tidal ranges than others.

Other factors could also affect the size of the tides, like the shape of a bay, the depth of the water, or the coastline’s geography.

This would be like saying: The gas pedal is the only thing that makes a car move. Therefore, the speed of the car is determined entirely by the gas pedal.

Wrong. Wrong. Hills, wind, road conditions, and friction can all affect how fast the car goes.

Similarly, gravity may create tides, but local conditions could influence how large the tidal ranges become.

___________

1. The problem is not that the author uses only one example. Even with many examples, the reasoning would still be flawed.
2. CORRECT. Gravity may induce tides everywhere, but local geographic conditions may determine why some locations have much larger tidal ranges than others.
3. The argument doesn’t depend on how high and low tides are measured.
4. Where was there a claim about “most” activity in the ocean? There wasn’t. It only talks about gravitational forces and tides.
5. Even if there are differences, it’s not necessary for the argument to distinguish them. The basic premise is that gravitational forces (whether from the sun or the moon) cause tides.