ggplot(data = iris) +
    stat_identity(aes(x = Sepal.Length, y = Sepal.Width) , geom= "point")

ggplot(data = iris) +
    stat_boxplot(aes(x=Species, y = Sepal.Length, ymax = ..upper.., ymin = ..lower..), geom = "errorbar")

ggplot(data = iris) +
    stat_boxplot(aes(x=Species, y = ..upper..) , geom = "point")

ggplot(data = iris) +
    stat_boxplot(aes(x=Species, y = Sepal.Length) , geom = "point")

Error: geom_point requires the following missing aesthetics: y