2nd post in series. Post 1 is here.
Before plunging in, I thought it would be helpful to give a brief description of what I mean by the term ‘worldview’. This is especially for those who might be unfamiliar with some of the ways that philosophers and theologians have defined how we think about things, or for those who have never had me for a theology or apologetics course. I want to give a short overview of the categories that I am using to define what a worldview is, and show how it fits together to give a comprehensive way of looking at our beliefs and lifestyle. Of course, there are different ways of getting at this. I am not claiming that this is the only or even the best way to understand worldview. It is just one way that I find helpful.
When I speak of worldview here, I am speaking in a broad philosophical sense. From that perspective, I would say that there is a Christian worldview, an Islamic worldview, a Hindu worldview, an atheistic-materialist worldview, etc. If I were speaking from an anthropological or sociological viewpoint, I would be interested in much more specific issues of belief and practice that are also cultural in nature. In that sense, you could say that there are various Christian worldviews, since there are different cultural ways of being a Christian. The same could be said for Hinduism, Islam, and other belief systems. However, I want to be clear that in this series I am speaking in terms of concepts that I would think to be basically common for Christians of most any stripe, as I articulate a Christian worldview. That does not mean that I am attempting to speak for everyone who claims to be Christian. It just means that I am attempting to faithful to the ‘big picture’ as I see it outlined in the basic source document for Christian belief, the Bible. 
So while we may think of a worldview as a complete “mental map of reality”, I am defining it here in terms of one’s basic presuppositions about the nature of things. It is one’s mental and emotional concept of the nature of the universe one inhabits. It directs one’s beliefs and behavior and can operate both consciously and unconsciously. More specifically, it has to do with how one approaches four essential aspects of inhabiting and getting along in the world. It has to do with how one answers four basic sets of questions that must be dealt with, consciously or not, in regards to living in the world. These questions have to do with knowledge, reality, value, and purpose.
How do you know? That is a basic question that all must face when deciding what is to be believed or not. Options require choice and choice requires reasons for going one way rather than the other. This area of philosophy is known as epistemology. It has to do with the theories of how knowledge is or is not possible, as well as with the study of different methods for obtaining knowledge. What is it that gives you warrant for believing something to be true? There are also debates concerning what qualifies as knowledge in the first place. Many proposals are available, including basing all knowledge on logic, or sense experience, science, authority, revelation, and others. The discussion among philosophers can get quite complicated and it is not my purpose to explore all of that here. I think it is possible to make some valid and helpful statements on a basic level without doing so. My views here will become more clear as we proceed.
What is real? This is essentially the question I raised in the first post, though it can be taken much farther. It concerns what God is like and whether or not such a being exists. It also deals with what human nature is, what is the world like (is it merely material, immaterial, both)? Technically we refer to it as ontology, or sometimes metaphysics though this term is broader and less precise. The question is about the nature of being, or existence, itself. Some possible answers include theism, pantheism, and naturalism.
What should I value? Humans have long wanted to know what is the highest good, the summum bonum, which merits our pursuit. Known as axiology this question actually has two different branches. We all have notions of what comprises beauty, and this leads us to consider questions of aesthetics. Parents and adolescents have, for many decades, argued over what actually constitutes music. This is just one example. Perhaps of more consequence is the discussion over what is morally right or wrong. Is there such a thing as justice? Is there an objective standard of good and evil? On what basis do we make moral decisions or resolve disputes over what is good and what is evil, whether it be personal behavior or social policy? This is, of course, the field of ethics and is of enormous concern for us as we approach the complexity of the issues that face contemporary society.
Is there a purpose to my life? Finally, people have an innate sense that life ought to have purpose and meaning, beyond the everyday tasks of getting by. Is there a plan or purpose for humanity? What is the meaning of life? Is history going somewhere, towards a goal, or is it all just a random ride to nowhere? And the biggest one, of all; is this life all there is? What happens to us after we die? Is this it, or is there a future to hope for? Is there some kind of ultimate cosmic justice, or is it true that life is a drag and then you die? Philosophers call this area of inquiry teleology. In theology some of the same issues are dealt with in eschatology.
One thing that should be clear is that each of these areas are intertwined. In fact, I have elsewhere likened them to four pieces of a mobile, hanging over a baby’s crib. The mobile, as a whole, represents a worldview. It exists in delicate balance with each of its parts. If the baby reaches up and swipes its hand against one part, causing it to move, a state of disequilibrium is created that causes the entire thing to shift until balance is restored. In a worldview, if you change something on one part, say in the area of how you see reality, you wind up changing the other areas as well. At least, that is the case if you are consistent. Most folks, on the other hand, have various contradictory elements in their worldview. Nevertheless, there is a tendency to move towards balance. Contradictions can cause a state of cognitive dissonance that seeks to resolve itself pushing you to become more consistent. That is, until consistency leads to a conclusion that you can`t handle. When that happens, it is probably time to think of changing your worldview.
So there it is. Worldview deals with knowledge, reality, value and purpose. I’ll be discussing how some of this fits together as I proceed. I hope it help make sense of things as we go.
1. My use of worldview here is more in line with the discussion by James Sire in The Universe Next Door than social science definitions such as found in Anthropological Insights for Missionaries by Paul G. Hiebert. Both approaches are valid, depending on your research goals.