I see the color and shape of the loaf of bread, but I can cross-check the shape using my sense of touch, confirming that it feels the same way that it looks.
I can also use hearing to investigate the bread by banging the loaf against a pot and hearing the ding. Further, the bread produces pleasurable stimulation of my senses of taste and smell.
The brain has different sensory systems but can combine them to form unified perceptions. In contrast
to hallucinations and dreams, which are hard to control, systematic experiments are possible: I can generate integrated and coherent sensations of the bread—for example, by simultaneously looking at it, scratching it, and eating it. Because I can make the bread cause these experiences, and because there is no evidence to support alternative hypotheses (e.g., I am hallucinating or dreaming), it is reasonable to conclude that the bread exists. Its reality is the best explanation of my diverse experience of it.