What type of qualities did Galileo consider as corresponding to physical reality?

Galileo distinguished between two types of qualities when discussing physical reality: primary qualities and secondary qualities. Primary qualities, as defined by Galileo, are the intrinsic attributes of an object that exist independently of perception. These include properties like shape, size, motion, and number, which can be measured objectively and are considered fundamental to the object's physical nature.

Secondary qualities, on the other hand, are those that exist in the mind of the observer and are related to the sensations they produce, such as color, taste, and sound. These qualities can vary depending on the observer's perception and context, making them less about the object's inherent properties and more about subjective experience.

Given this distinction, the correct answer highlights the concept that primary qualities are those that correspond directly to the physical reality of the object itself, making them essential for a scientific understanding of the world as Galileo proposed. This differentiation laid foundational thoughts for the development of modern scientific inquiry and philosophy regarding the nature of objects and perception.

Understanding this concept helps underscore the importance of empirical measurement in science, a fundamental aspect of which is recognizing the difference between how we perceive qualities and the qualities that exist independently of perception.