Another important constituent of worldview is metaphysics. Metaphysics refers to the study of things which are beyond physics, that is, things unseen. Metaphysics concerns with investigating things that exist or real. It tries to conclude what things exist, and what things do not exist. Some people say that the things exist if they can give effect to the 5 senses and they can be verified through scientific experimentation. Things that cannot be proven through scientific method is considered as not real...do not exist.
For some other people, they claim that things that logically connected with other things, exist or real; even though we may not be able to see them. For example, we can conclude that a person named Zaid exists because we have seen a birth certificate that has the name Zaid written on it, we have seen a photograph of Zaid, we have seen a house with the name Zaid written on the gate...therefore, it is logical to say that Zaid exists because we have seen other information that is connected to Zaid, even though we have not seen the person named Zaid personally.
Others think that things that exist are things that are functional, that is, they work and facilitate in the achievement of some specific goals. For example, if a thing that looks like a car but does not function as a car, that thing is not real...it may be just a piece of junk.
People who adopt a materialistic worlview, do not believe in the existence of the unseen things; people who believe in rational thinking argue that it is logical to conclude that the unseen things exist through speculation but they also claim that they cannot say that the unseen exists with certainty. The believe in what is real/exist and what is not real and does not exist, has implications on a person's life. Those who believe that only material things exist, of course do not believe in the existence of supernatural beings or the unseen things such as God, heaven and hell, etc. This, of course, affect the way a person lives his/her life. If he/she does not believe in God, then, say for example, his/her ethics and morality is from the creation of human mind which may differ from person to person, place to place, time to time, or culture to culture.
In metaphysics, we learn about cosmology, that is we attempt to investigate about the universe, whether it is created or exist by chance, or it has a beginning and an ending, whether the universe has a beginning but eternal, whether there is life after death (another universe or world) and etc. Why does the study of cosmology fall into metaphysics? It is because we try to find answers on questions such as 'is the universe created?' We cannot answer this question by scientific experimentation, so people use speculation which is the method for answering metaphysical questions. For Muslims, we can know metaphysical truth with certainty through Revelation because we admit that the mind has limitation to think of the unseen reality, therefore we need other sources of knowledge.
Besides cosmology, we also study anthropology, that is the study of man. We try to find out whether man is created or evolved from other much much inferior beings... ( Is it logical for a superior being to evolve from a much much much inferior being?), to find out the nature of man, that is, what is man made of? Is he body, or mind and body, or mind, body and soul? what is the function or mind and soul? where is he coming from and where is his destination? why is here on earth? etc. We also investigate about teleology in metaphysics. Teleology seeks to find out about purpose of existence such as purpose of life, purpose of human being, purpose of the universe, purpose of everything.
A person's belief whether metaphysics is real or not affect his/her strategy of living. Those who claim that metaphysics is a pseudo-science, or course would argue that there is no life after death, no heaven and hell, the universe is eternal, death means the end of life and nothing will happen just that human body will become soil. The logical consequences of this proposition is that people will try to seek worldly happiness in the form of material things such as nice house, own lots of property because they believe they have to create heaven on earth, etc.
Part 3 in another post :)