Obstinacy in a bad cause, is but constancy in a good.

-Browne, SirThomas
^5  Religio Medici (published1643), pt.1, section 25.

Thehistoryof science, likethehistoryof all humanideas, is a history of irresponsible dreams, of obstinacy, and of error. But science is one of the very few human activitiesöperhaps the only oneöin which errors are systematically criticized and fairly often, in time, corrected. This is why we can say that, in science, we often learn from our mistakes, and why we can speak clearly and sensibly about making progress there.

-Popper, Sir Karl Raimund
  Conjectures and Refutations (published1963), ch.10.

'Tis known by the name of perseverance in a good cause,öand of obstinacy in a bad one.

-Sterne, Laurence
^67  Toby.Tristram Shandy, bk.1, ch.17.