Steven Weinberg on scientific progress

I'm a big fan of this passage from The First Three Minutes, Chapter V (emphasis added):

In following this account of the first three minutes [of the universe], the reader may feel that he can detect a note of scientific overconfidence. He might be right. However, I do not believe that scientific progress is always best advanced by keeping an altogether open mind. It is often necessary to forget one's doubts and to follow the consequences of one's assumptions wherever they may lead--the great thing is not to be free of theortical prejudices, but to have the right theoretical prejudices. And always, the test of any theoretical preconception is in where it leads. The standard model of the early universe has scored some successes, and it provides a coherent theoretical framework for future experimental programs. This does not mean that it is true, but it does mean that it deserves to be taken seriously.

It certainly begs the question which prejudices are the right ones!