Paradigm shift would not be unlike a political revolution

There is no doubt that paradigm shifts occur.  After an examination of the reasons that it has been claimed that people cannot choose, or voluntarily change, their paradigms, lets examine the implications of the fact that people do voluntarily change their paradigms from time to time and spell out some of the ways that this comes about.

There are a number of reasons why one supposedly can't do this at an intentional level.  Basically, because everything that one perceives and all the ways that one describes what one perceives, everything that one thinks and all the ways what one analyzes what one thinks, everything one feels and all the ways that one sorts and arranges those feelings, and all the appraisals one makes and all the justificatory maneuvering one goes through with those appraisals are all paradigm-dependent (theory laden, perspectively determined), one cannot achieve the distance it would take to bring the whole apparatus under scrutiny.

Paradigm change does occur as a result of:

• Exposure to alternative forms of life
• Paradigm failure in new and perplexing circumstances 
• paradigm debates are not really about relative problem-solving activity...Instead, the issue is which paradigm should in the future guide research on problems, many of which neither competitor can yet claim to resolve completely. A decision between alternate ways of practising science is called for, and in the circumstances that decision must be based less on past achievement than on future promise. The man who embraces a new paradigm at an early stage must often do so in defiance of the evidence provided by problem-solving. He must, that is, have faith that the new paradigm will succeed with the many large problems that confront it, knowing only that the older paradigm has failed with a few. A decision of that kind can only be made on faith...
• It also happens at an intentional level
• The clearest and most convincing response to the claim that people cannot engage in intentional paradigm reform is that they do
• Intentional paradigm change is intentional paradigm choice, though never de novo
• There are ample models for such intentional change
• The Transtheoretical Model is a model of intentional change. It is a model that focuses on the decision making of the individual. Other approaches to health promotion have focused primarily on social influences on behaviour or on biological influences on behaviour. For smoking, an example of social influences would be peer influence models (Flay, 1985) or policy changes (Velicer, Laforge, Levesque, & Fava, 1994). An example of biological influences would be nicotine regulation models (Leventhal & Cleary, 1980; Velicer, Redding, Richmond, Greeley, & Swift, 1992) and replacement therapy (Fiore. Smith, Jorenby, & Baker, 1994). Within the context of the Transtheoretical Model, these are viewed as external influences, impacting through the individual.
• Intentional changes to ones original, or some subsequent, paradigm-in-place can happen in response to:
• Discontent - what happens when adolescents rebel against the orthodoxies of their childhood
• Exposure to other forms of life as ones culture increases "scale" - what happens when young people go away to university or when older people read books and take video courses.
• Conversion experiences and thunderbolts - what happened to Paul on the road to Damascus and Newton under the apple tree

The Structure of Scientific Revolutions