The discussion revolves around the various branches of engineering, clarifying common confusions among students about choosing majors like mechanical or chemical engineering. The speaker notes that historically, engineering types were limited, but advancements in technology have led to a multitude of engineering disciplines. However, they emphasize that these can generally be categorized into six major fields known as the big six: mechanical, chemical, civil, electrical, software, and industrial engineering. Each field has its own distinct courses and career paths. For example, mechanical engineers focus on designing and optimizing products across industries such as automotive and aerospace, while the curriculum includes key subjects like thermodynamics and materials mechanics. Job roles for mechanical engineers can range from product design engineers to manufacturing engineers specializing in the production processes. The speaker intends to elaborate on these categories and explain how other engineering types relate to the big six, reinforcing the idea that many engineering roles are interrelated or derivatives of these core disciplines.