Should you capitalize economics in a sentence?

absolutely

No. Economics is an academic discipline, like philosophy, algebra, music and chemistry. As such, it is not generally capitalized. However, when discussing a specific academic course at a learning institution, such as "Economics 101", or "Industrial Economics", it is proper to capitalize.

Correct: Ayn Rand's understanding of economics was naive.

Correct: I'm certain I passed my Economics and Asian Anthropology exams.

Incorrect: I enjoy learning about Economics and Literature.