The word theology, when broken down, (theos - God, logia - knowledge) is simple to define. Theology is the study of God. This may sound contrite to those who do not believe in God, but simply because they deny His existence does not mean they are neutral in the matter. Atheism is a theological statement as equally as theism is.
Atheism is the belief that there is no transcendent God out there somewhere outside of this universe. I would say there are two types of atheists, the secular humanists, and the cosmic humanists. These are just titles, but let me explain what I mean by them.
Secular Humanists would be those who believe that there is nothing outside the physical realm. There is no such things as the spiritual or the soul. Likewise, the majority of them will believe that man is the chief aim of man. Meaning we make what we wish of this life and we alone are in control. Besides us (plus perhaps the possibility of extra-terrestrials,) we are alone in the universe. It’s just us.
The cosmic humanists are similar, yet strikingly different. Using words like ‘they’ and ‘most’ may not accurately portray this group because their beliefs can be diverse, but in generalities, what I mean by cosmic humanists are those who believe that the spiritual is very real, indeed it may be that most of the time the physical is more an illusion or an imprisonment of your mind than real. Some call them pantheists (all is God), but even then it is not clear that they believe in God, for if all is God, then you could also say that all is anything you want, because all is one and the same. I know that I have not done their beliefs justice in this small excerpt. For many would cringe at being labeled in with atheists while others would be berated that I called the physical world an imprisonment, while still others would agree in general with my very rough estimate of their beliefs.
Polytheists are those who believe in many Gods, and while many might attempt to place Christianity as a polytheistic religion as they believe in the Trinity, that would be no small misrepresentation of the principle of the Trinity. The Bible is adamant that there is only one God. What the Trinity is, is a description of God’s make-up. It is hard, even for Christians to grasp, the idea of three independent persons within one God. Like water, ice, and vapor all being one particle, or if you will accept it, man being made up of the physical, the spiritual, and the mental. In the same way that I am not three different entities, Jared the physical, Jared the spiritual, and Jared the mental, but I am all three distinctions, but one entity. Jared Williams. Not even Christians fully understand this distinction that is made by the Trinity, that there is God the Father, God the Son, and God the Holy Spirit, but we do know that God is the Trinity; He is also the one and only God. In this, Christianity must be labeled under the title of monotheism. The belief in a “one and only God.”
These are the different general ideas generated by Theology. The next step in theological study would be, once you choose what you believe about God, you then need to know the consequences of what you believe. If there is no God, what are the consequences of that belief. If you believe in this or that or those gods, what is He or She or They like? And what does that mean for you?