The metaphor of “lenses” has popularly been employed to illustrate their function: we view the world through a particular set of lenses. We do not look at the lenses themselves but through them onto the world, nor do we usually consider them but stare as if they don’t exist. Further, it is the color of the lenses that dictate how we perceive. In this sense they are presuppositional, pre-cognitive, and provide a perspective (worldview).
In his insightful discussion of worldview, N. T. Wright outlines four elements to a worldview: (1) they provide the stories, particularly a controlling story, through which humans perceive reality, (2) these stories then provide the answers to a set of “basic questions that determine human existence” (who are we, where are we, what is wrong, what is the solution, what time is it?), (3) these beliefs are expressed in cultural symbols, and (4) give way to a praxis, “a way-of-being-in-the-world”.
The beliefs that constitute part of a worldview concern the ultimate questions of life, those which all other intellectual and practical pursuits build upon. They are in this sense “foundational”, grounding and conferring justification on our thinking and living. They are not uninvolved beliefs however. They provide both an identity (who are we), and a general praxis (where are we, what is wrong, what is the solution, what time is it?).
 The illustration can be somewhat misleading, as worldviews cannot simply be “taken off” and exchanged for a moment, as a pair of lenses might be.
 It is both appropriate to speak of ‘perceiving’ and inappropriate to speak of simply ‘seeing’ because at a more fundamental level, worldviews are constitutive of the human person and hence human cognition. To extend the metaphor, we cannot use our eyes at all if we are not wearing lenses. Indeed, the lenses are our eyes. We might wish to speak of prescription lenses without which all is a blur, but when worn, things come into focus.
 The New Testament and the People of God, 124-5