"Sense data are much more controversial than qualia, because they are associated with a controversial theory of perception - that one perceives the world by perceiving one's sense-data, or something like that"

This quote by David Chalmers is referring to the philosophical dispute surrounding sense information and qualia. Sense information is the details that is gathered by the senses, such as sight, noise, odor, taste, and touch. Qualia is the subjective experience of the senses, such as the sensation of warmth or the taste of a strawberry. Sense data is more controversial than qualia since it is connected with a questionable theory of perception, which recommends that a person perceives the world by viewing one's sense-data. This theory is questionable due to the fact that it implies that the world is not directly viewed, but rather is perceived through the interpretation of sense data. This theory has been disputed by philosophers for centuries, and it is still a topic of discussion today.