Often times while in debate or discussion with someone, they may say something that they state as though it was truth, but upon further examination you find that in fact their statement does not prove anything. What they have committed is what is commonly known as a Logical Fallacy.
The discovery of Logical Fallacies within an argument is a very very important practice in defending your faith. They are very common in the arguments of atheists, Muslims, Mormons, and pretty much every other religion, including Christianity. It is because of their importance that I will list what I think are the ten most common Logical Fallacies that get committed, not just so that we can uncover them in an opponent's argument, but so we can avoid using them ourselves when we are called upon to give a defense for the hope that is in us.
Ad Hominem (Appeal to the Person) - This is the fallacy where the character of the person is attacked. By paying close attention you will find that ad Hominem is used more often than any of the fallacies you will see in this list. Often times you will see this used by atheists when trying to convince others of their position. While it may be intimidating to hear, it may be seen as either a sign of immaturity or a lack of defense in your opponent’s argument. There have been multiple times where I have cut off discussions because even after warning, my opponent could not refrain from throwing nothing but vulgar insults in my direction. If you ever come across this in a discussion, I encourage you to stop your opponent and simply ask, "was it your goal to lower my self-esteem by insult or actually prove something by fact?"
In his best seller The God Delusion, Richard Dawkins uses this fallacy as a personal favorite, often filling page after page with insults without providing any evidence for his particular view. The sad thing is that many Christians have been lead away from their faith as a result to Dawkins and other authors from his platoon.
Appeal to Numbers - This is the fallacy that is committed when someone tries to refer to the results of polls or surveys in an attempt to show that their viewpoint is valid because a certain percentage of the public agrees with them. While often serving a purpose in speeches and presentations, appealing to numbers is however quite incapable of proving anything in an argument.
Circular Argument or Begging the Question - This fallacy occurs when someone uses what they are trying to prove as part of the proof of that very thing; or they just simply assume it to be true without providing any evidence. These are sometimes very difficult to point out in a debate but if found it can be very effective to reveal it.
Appeal to Authority - This fallacy is committed whenever someone cites another person who agrees with them, even though the person has no expertise in the topic of the argument.
Appeal to Pity - This fallacy is committed when someone tries to manipulate the reception of their argument by using pleading and emotion to convince or manipulate people.
False Dilemma - This occurs when only two choices are given when in fact there could possibly be more. You may come across this when people try to intellectually back you into a corner by forcing you to validate one of two options when in fact both of them are false.
Genetic Fallacy - This is what happens when someone tries to either credit or discredit a claim because of its origin or history.
Non Sequitur - This refers to an argument that does not properly follow from a premise or the conclusion. Like many others this is often difficult to catch in a conversation because it can be very well hidden.
Red Herring - This occurs when someone brings in irrelevant facts to the topic at hand. Often this happens when a person can no longer defend their position so they have to bring in a new topic in order to support their view.
Straw Man - This fallacy occurs when someone produces a somewhat false argument that is meant to be proven false. Think of a straw man, like in the Wizard of Oz, he is easy to build but is formed so that he can make a fool of his target. This fallacy is often committed to make someone look unintelligent and humiliated which will as a result cause him to lose respect in the argument.