Probability

Probability is the degree to which an event as likely or unlikely to occur.

The Two Types of Probability
Under this general definition, there are two more specific types of probability:
 * Perceived probability, or the perception a person has about the likelihood or unlikelihood of an event given knowledge of some but not all of the factors that will determine the outcome;
 * Actual probability, or the likelihood that an event will occur given all of the determining factors.

To understand the difference, imagine that a person is standing in front of you, and has a ball in one hand, behind his back. If I ask you, "What are the chances that the ball is in his right hand?" you'll likely say, "50%," because you know that he has two hands and only one ball, making it equally possible that the ball be in one hand as in the other. That is the perceived probability -- your perception of the chances that events will turn out one way or the other.

But the perceived probability only exists because you can't see behind his back. The person holding the ball has more information than you do -- he knows what hand the ball is in -- and so he knows that the ball is actually in one hand, and not in the other. Thus there is no actual probability in this case. There is no actual "50% chance that the ball will be in any one hand." The 50/50 probability is only a perception on your part, stemming from your lack of information, because you can't see behind his back.

The difference between perceived and actual probability is important in the area of creation and evolution, because it addresses a rarely considered issue about the universe itself: are there any random and/or free will events in nature, or is everything determined by the laws of nature? Or, to put it another way, is everything determined, or not?

Existence and Non-existence
There are a number of views regarding the existence or non-existence of these two types of probability:
 * Determinism holds that there is no such thing as actual probability, but only perceived probability, because natural law or the will of God determine all events, and we only perceive things to be probable or improbable because of our inadequate knowledge of the events, laws, and/or will of God that determine all events;
 * Nondeterminism holds that actual probability exists, because not all events are absolutely determined, being affected either by free will, random events, or both.

These views relate to creation and evolution through the following views:
 * Deterministic evolutionism holds that the emergence of life occurred by necessity as a result of the laws of nature, and that all future changes in life and the universe will occur according to those same laws.
 * Nondeterministic evolutionism holds that the emergence of life occurred as a result of chance and natural law, and that future events will depend on future chance events;
 * Deterministic creationism holds that the creation of the Earth, life, fall of Man, Flood, and the rest of human history were all necessary outcomes of the divine plan;
 * Nondeterministic creationism holds that the Earth and Life were created by a free choice by God, that humanity freely chose to eat the fruit and deteriorate into violence, and that God, despite His foreknowledge of these events, was not the author of them.

Evolution and Probability

 * Main Article: Mutations

The probability of evolution via related mutations has been shown to be impossible mathematically. First and foremost, mutations are rare. They happen on average about once in every 10 million duplications of the DNA molecule (107, a one followed by 7 zeroes). The problem comes when you need a series of related mutations to occur. The odds of getting two mutations that are related to one another is the product of their separate probabilities, one in 107 x 107 or 1014, a one followed by 14 zeroes, a hundred million million! That would barely change the shape of a fly wing, for example -- this is a long way from a truly new structure, and certainly a long ways off from turning the fly into anything other than a fly.

Now since evolution needs the consistency of related mutations to work at all, what are the odds of getting three related mutations? That is one in a thousand million million million, or 1021. Suddenly, the ocean isn't big enough to hold enough bacteria to make that chance likely. Even at just three related mutations, evolution, with mutations as its mechanism, is woefully inadequate to produce truly massive evolutionary changes.

Related References

 * Probability by Answers