George Berkeley and the absence of matter
The philosopher's chair
Berkeley spent eighteen years as Bishop of Cloyne without believing in the material world as everyone else understood it. His philosophy was *esse est percipi*—to be is to be perceived. To exist is to be observed. In a quiet village in Cork, he sat in a wooden chair (which doesn't really exist unless you're looking at it) and wrote and thought and argued about perception and reality. When he died in 1753 they took him to Oxford to bury him. The chair stayed in Cloyne Cathedral, where you can still sit and think about what "sitting" means.
Stone, built to last
The round tower
The round tower beside the cathedral is roughly thirty metres high and entirely intact. It's one of the better-preserved examples in Ireland. Built sometime between the ninth and twelfth centuries—no one argues much because the tower just stands there being a tower, which is what towers do. It was built as a refuge and a bell tower. It's still there. You can walk around it. It makes you think about persistence, which is funny because Berkeley would have said it's only persisting because you're looking at it.