Traditionally, studies of brain function have focused on task-evoked responses. By their very nature, such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive, it ignores the alternative possibility: that brain functions are mainly intrinsic, involving information processing for interpreting, responding to and predicting environmental demands. I shall argue that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain's energy resources. Understanding intrinsic activity will require integrating knowledge from cognitive, systems, cellular and molecular neuroscience. Ultimately, understanding conscious awareness will require an appreciation of the fundamental role played by intrinsic activity in brain function.