Introduction:
David Hume, an influential philosopher of the 18th century, proposed the laws of association to explain the nature of human thought and reasoning. According to Hume, these laws are the mental counterpart of the laws that govern the physical universe. In his view, the laws of association provide the basis for how we form ideas and make connections between them.

The Laws of Association:
Hume identified three fundamental laws of association that govern the way our minds link ideas together:

1. Similarity: The principle of similarity suggests that we tend to associate ideas that resemble each other. For example, if you see a red ball, you may associate it with other red objects or balls.

2. Contiguity: The principle of contiguity states that we associate ideas that are closely related in time or space. For instance, if you smell a particular scent, you may associate it with a specific location or event where you previously encountered that scent.

3. Causality: The principle of causality asserts that we associate ideas of cause and effect. When we observe one event regularly followed by another, we tend to link them together and infer a causal relationship. This law is crucial for our understanding of the world and our ability to make predictions based on past experiences.

Explanation of the Correct Answer:
The correct answer is option 'B' - Gravity. Hume did not include gravity as a fundamental law of association. This is because gravity is a physical force that governs the behavior of objects in the physical world, rather than a principle that describes how our thoughts and ideas are connected.

Hume's laws of association primarily focus on the mental processes involved in forming and linking ideas together, whereas gravity is a concept that falls within the realm of physics. While gravity may have an indirect influence on our thoughts and experiences, it is not considered a fundamental law of association according to Hume's framework.

Conclusion:
David Hume's laws of association provide insight into how our minds form connections between ideas. By understanding the principles of similarity, contiguity, and causality, we can better comprehend the processes underlying human thought and reasoning. While gravity is an important physical force, it is not classified as a fundamental law of association in Hume's philosophical framework.