Usually, the word "paradigm" is used to describe a thought pattern or methodology that exists during a certain period of time. When scientists refer to a scientific paradigm, they are talking about the prevailing system of ideas that was dominant in a scientific field at a point in time. When a person or field has a paradigm shift, it means that they are no longer using the old methods of thought and approach, but have decided on a new approach, often reached through an epiphany. When paradigm is pronounced, it has a silent "g" and sounds like "pare-eh-dime." Groups that experience paradigm shifts can be social groups, like political or religious groups, as well as groups engaged in scientific discourse.
Changes in thought paradigms have shaped scientific, political and social progress throughout history. When a group experiences a paradigm shift, that means that something that was widely accepted by the group in general is no longer accepted. It usually refers to significant change which affects the basis of other related information, especially that which was deduced from the old paradigm and is incorrect under the new one. This type of change can happen when there emerges a piece of irrefutable evidence that a major theory is incorrect, or if a member of the group finds new information that forces the group to reinterpret its universal position. Examples of notable events that caused scientific paradigms to shift include the acceptance of the theory of plate tectonics in geology and the development of Newtonian physics and Einstein's theory of relativity.
Though a man named Thomas Kuhn popularized present-day use of the word in reference to sweeping changes in scientific thought, the word is often used by individuals to describe a major change in personal thought. If an underachiever suddenly decides to dedicate herself to excellence in her career, or if a heavy drinker decides to give up the bottle and spend more time with his children, those people might say they had a shift in their paradigms that led them to their life changes. People can also experience shifts in their religious paradigms and decide to start or stop engaging in religion, change religion or refocus how they observe religious beliefs within an existing structure. Some people feel that this use is incorrect and dilutes the true meaning of the word.
A paradigm shift does not mean that everyone has agreed to go along with it. Some groups engaged in scientific discourse continue to refute changes in scientific thought even long after their positions have been factually disproven to an extent that satisfies most of the general public. An example of this might be a group that promotes acceptance of alchemy as a viable science, or a group that continues to promote the belief that the Earth is flat despite evidence that it is actually round.