Non-informative Priors

"If nothing is known about the value of a parameter, then a non-informative prior is used&#emdash;typically, this is a rectangular distribution over the feasible set of values of the parameter. Another approach, the empirical Bayes method, utilizes the data to inform the prior distribution. [?] "
Upton & Cook (2002)

"Non-informative prior distribution: A prior distribution which is non-commital about a parameter, for example, a uniform distribution."
Everitt (1998)