The following quotes were compiled by Chuck Bloch and listed in:
Science as a Way of Knowing.
It is a capital mistake to theorize before one has the data. Insensibly one
begins to twist facts to suit theories, instead of theories to suit facts.
– Sir Arthur Conan Doyle
It is also a good rule not to put too much confidence in experimental
results until they have been confirmed by theory.
– Sir Arthur Eddington
First get your facts; then you can distort them at your leisure.
– Mark Twain