From Norman Geisler’s book Irrefutable Proof Christianity is True
Provided a logical argument is valid, we can arrive at a conclusion with absolute certainty through deductive reasoning. In contrast, we can only obtain a certain level of probability with inductive reasoning. (Unless it’s a perfect induction which is rare.) Both types of reasoning are valid. Yet, we live in a scientific age and the scientific method is based on inductive reasoning. As a result, people tend to place more value on inductive reasoning which uses an evidence-based approach to discovering truth. Here are some evidence-based, inductive arguments for God.
When we look at life, we see irreducibly complex systems that depend on each other for existence. This is true at a macro and micro level. The human body is composed of systems such as the pulmonary system, the digestive system, the skeletal system, etc. These systems must all be fully functional because they depend on each other. Darwinian evolution is not an adequate explanation for how multiple interdependent systems can originate, especially between both male and female organisms simultaneously. Nor has macro evolution ever been observed.
The Anthropic Principle
Conditions on Earth seem to be fine-tuned for life. There are over 100 factors that are required to make life on earth possible. Some of these factors are the amount of oxygen in the air, the distance of the earth from the sun and its tilt, the characteristics of water, the strength of gravity, and even the presence of Jupiter in the solar system.
Argument from Specified Complexity
Life is complex. The more we study and analyze it, the more complexity we discover. Even Richard Dawkins admits that there is the equivalent of 1,000 copies of the Encyclopedia Britannica inside a simple single celled organism. Recent discoveries in genetics and DNA have added to our understanding of just how complex and specified life is. Scientists have discovered that the mathematical pattern of our DNA is the same as that of human language. We speak of the “DNA code” and scientists have reverse-engineered DNA and are now attempting to program new life forms through synthetic biology. It is reasonable that a program requires a Programmer and that specified complexity requires an Intelligent Designer.
Argument from First Cause
We now know the universe is not eternal but had a beginning. We know through the Second Law of Thermodynamics that the amount of usable energy in the universe is decreasing. We also know the universe is expanding. If we extrapolate backwards we come to a singularity. We have discovered cosmic background radiation coming at Earth from all directions and the ripples or “galactic seeds” which were predicted if such a singularity were to have occurred. We also know through Einstein’s Theory of Relativity (which has recently been proven through experimentation) that space, matter and time are co-related (cannot have one without the other) which proves the universe had a beginning. If the universe had a beginning, it must have a Beginner.
The idea of a multi-verse (to which we have no evidence) does not solve the issue of causality, but merely pushes it back. There cannot be an infinite number of universes causing universes. There would still need to be a Beginner.