''Keep the good, drop the bad...'' The scientists drop the erroneous (bad) ideas, and keep the true (good) ideas.
They thought the earth had no magnetic field. Wrong. Drop the idea. etc etc
Analogous to: "Killing Infidels used to be is acceptable. It is no longer acceptable to do this.
We no longer advocate it in the Tolerant Thread sect of Reformed Islam, although the Sunni's may try to assassinate us. The United Ba'hai Congregationals for All Humanity also take this position."
