Introduction: a sketch of the sources and nature of belief, justification, and knowledge

Before me is a grassy green field. It has a line of trees at its far edge and is punctuated by a spruce on its left side and a maple on its right. Birds are singing. A warm breeze brings the smell of roses from a nearby trellis. I reach for a tall glass of iced tea, still cold to the touch and flavored by fresh mint. I am alert, the air is clear, the scene is quiet. My perceptions are quite distinct.