Which philosophy states that reality consists only of matter and energy?

Materialism is the philosophy that asserts that reality is fundamentally composed of matter and energy. This perspective emphasizes that everything that exists can be explained in terms of physical substances and their interactions. In other words, materialists believe that all phenomena in the universe, including thoughts, emotions, and consciousness, ultimately arise from material interactions.

This philosophical viewpoint contrasts with others that incorporate non-material elements into their understanding of reality. For example, naturalism, while closely related, can include the belief in natural laws and processes, but it might not strictly limit itself to matter and energy alone. Realism typically asserts that reality exists independently of observers but does not specifically restrict reality to just material components. Idealism, on the other hand, posits that reality is fundamentally mental or immaterial, focusing on ideas and consciousness rather than physical matter.

Given this context, materialism is clearly the most accurate choice for a philosophy asserting that reality consists solely of matter and energy.