NATURAL THEOLOGY

For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: (Romans 1:20)

The field of apologetics may be divided into two sorts: offensive (or positive) apologetics and defensive (or negative) apologetics. Offensive apologetics seeks to present a positive case for Christian truth claims. Defensive apologetics seeks to nullify objections to those claims. Offensive apologetics tends to subdivide into two categories: natural theology and Christian evidences. 

The burden of natural theology is to provide arguments and evidence in support of theism independent of authoritative, divine revelation. The cosmological, teleological, moral, and ontological arguments for the existence of God are classical examples of the arguments of natural theology. 

Natural theology is that branch of theology that seeks to provide warrant for belief in God’s existence apart from the resources of authoritative, propositional revelation.

Most unbelievers are ignorant of natural theology and have never confronted a Christian who is ready to offer carefully formulated arguments for his belief in God. Having logically valid, clearly formulated arguments is going to make you look smart and increase your credibility in their eyes, which will only make your witness more effective.

   Natural Theology Arguments

(1) Kalām Cosmological Argument

The kalām cosmological argument may be formulated as follows: 

1) Whatever begins to exist has a cause. 

2) The universe began to exist. 

3) Therefore, the universe has a cause.

(2) Teleological (Fine-Tuning) Argument

The teleological argument appealing to cosmic fine-tuning might be formulated as follows: 

1) The fine-tuning of the universe is due to either physical necessity, chance, or design. 

2) It is not due to physical necessity or chance. 

3) Therefore, it is due to design.

(3) The Moral Argument 

This argument is as follows: 

1) If God does not exist, objective moral values and duties do not exist. 

2) Objective moral values and duties do exist. 

3) Therefore, God exists.

(4) The Plantinga’s Ontological Argument

We can formulate Plantinga’s version of the ontological argument as follows: 

1) It is possible that a maximally great being exists. 

2) If it is possible that a maximally great being exists, then a maximally great being exists in some possible world. 

3) If a maximally great being exists in some possible world, then it exists in every possible world. 

4) If a maximally great being exists in every possible world, then it exists in the actual world.

5) If a maximally great being exists in the actual world, then a maximally great being exists. 

6) Therefore, a maximally great being exists.

Further study: 

* Reasonable Faith by Dr. William Lane Craig

* I Don't Have Enough FAITH to Be an ATHEIST by Dr. Norman L. Geisler and Dr. Frank Turek

* Lee Strobel's books "The Case for.."

* The Nature of Necessity by Dr. Alvin Plantinga 

* WHERE THE CONFLICT REALLY LIES by Dr. Alvin Plantinga 

* When Skeptics Ask by Dr. Norman L. Geisler and Ronald M. Brooks

* THE BLACKWELL COMPANION TO NATURAL THEOLOGY by Dr. William Lane Craig and J. P. Moreland