What is a paradigm? It is a perspective on the world or within a specific discipline. It tells us what is important and how the world works. It determines our beliefs and values. It colors all our perceptions of what is happening and how we respond to reality. It determines what problems we choose to address and how to address them. The fact is: Everyone is encapsulated by a prevailing paradigm.
A paradigm, therefore, is a framework or model that helps to interpret and deal with reality. It serves as a perceptual map, to use the words of Edward de Bono, or mental model, as described by Peter Senge. The two top exponents of the role and influence of paradigms , however, are Thomas Kuhn and Joel Barker.
Kuhn talked about the power of a paradigm from scientific and academic vantage points. He postulated that scientific endeavors were greatly influenced by it. This led to his famous definition of a paradigm as consisting, for example, of laws and theories that provide tradition behind research, principally scientific research. 
Joel Barker took the substance behind Kuhn and applied it to business and other environments. He defined a paradigm as a set of written and unwritten rules and regulations that defines boundaries of behavior. 
A paradigm, of course, is not something that is "bad" or "evil." It is a consequence of being human and requires a means to interpret and deal with our surrounding world. In other words, it provides order, a means to predict the future, comfort , explanations , and enhances communication.
A paradigm is, therefore, really a belief system to explain how "things" work. It provides a schema to interpret the past and present as well as what occurs in the future. It is so strong that it influences our choices.
It is those very pluses, however, that generate the minuses associated with a paradigm. A paradigm can lead to rigidity in thought (even dogmatism), screen out innovative ideas, filter facts, and, perhaps most importantly, restrict people's perception and responses to reality. All that translates into leading to what I refer to as "professional blinders" and "hardening of the synapses." Unlearning becomes as difficult as learning.
Of course, change happens and presents complications before a paradigm. After a while, however, the stranglehold of a prevailing paradigm loosens. A paradigm shift occurs, thus opening the road to a new one. Problems begin to surface that cannot be addressed adequately by the prevailing paradigm. Anomalies become increasingly prevalent . The entire paradigm can eventually, perhaps even suddenly, come into disrepute. Failure occurs when applying the existing rules. Discontent begins to arise with practitioners , who question the very fundamental precepts of the dominating institutions and prevailing beliefs and values. As Kuhn noted, recognition of an anomaly can lead to discoveries that can weaken the prevailing paradigm.
Challenging the prevailing paradigm, of course, is not easy because a prevailing paradigm does not embrace creativity that well. The tools and technologies for the new paradigm lack maturity. A comprehensive body of knowledge does not exist. Most importantly, the subscribers to the new paradigm often face ridicule, even ostracism. That is because the adherents of the prevailing paradigm find themselves potentially on the losing end. The supporters of the existing paradigm begin to feel threatened. This sense of feeling threatened grows the higher one moves up the "food chain" because the potential to lose more is greater.
Despite the protectors of the status quo, change continues to march forward. A metanoia, to use Senge's term , occurs; that is, a shift of mind happens. Followers of the old paradigm fall into the ranks of the new one, more out of the heart than the head. Old and new adherents alike see a gradual breakdown in the paradigm, which causes a schism to surface. At a more frequent level, anomalies arise that whittle away at the very foundation of the prevailing paradigm.
Of course, the new paradigm does not discard the entire prevailing paradigm. Quite the contrary. Instead, it absorbs much of what is good but does not apply in the same manner. What gives the new paradigm the advantage over the prevailing one is that the former solves problems that the other could not.
 Thomas Kuhn, The Structure of Scientific Revolutions , University of Chicago Press, Chicago, 1970.
 Joel Barker, Paradigms , HarperBusiness, New York, 1993, pp. 31 “32.