"The best qualification of a prophet is to have a good memory. "
--Marquis of Halifax,
This quote is very applicable to statistical models which require long periods of past data in order to be reliably estimated.
"Some things are so unexpected that no one is prepared for them. "
--Leo Rosten in Rome Wasn't Burned in a Day
This is particularly relevent to non-stationary processes such as the the climate and the business world. For example, the appearance of the Antarctic ozone hole in the mid 1970s was quite a surprise.
"An unsophisticated forecaster uses statistics as a drunken man uses lamp-posts - for support rather than for illumination. "
--After Andrew Lang
Careful application of statistics is essential for obtaining and judging predictions and can provide much insight into the assesment of skill in the predictions.
Post-analysis of predictions is often very revealing especially concerning model weaknesses.
"Prediction is very difficult, especially if it's about the future."
--Nils Bohr, Nobel laureate in Physics
This quote serves as a warning of the importance of testing a forecasting model out-of-sample. It's often easy to find a model that fits the past data well--perhaps too well!--but quite another matter to find a model that correctly identifies those features of the past data which will be replicated in the future.