What is a false dichotomy? A false dichotomy is a logical fallacy that seeks to present a scenario, and give only two options. An example of this fallacy might be: "So, have you stopped beating your wife yet?" If I asked you this question, you would be shocked I am sure! If you say, "yes", then this indicates you were in fact at one time beating your wife, but have since seemingly stopped, seeing the error of your way.
If your respond with, "no" this indicates that you have indeed continued to beat your wife, and have not stopped at all.
The answer is as you might have guessed, neither! As a Christian who has the standard of authority as the Bible, I believe that God created and gave us a mind to use, and that logic and reason comes from the source of all wisdom, God Himself. And if logic and reason are a gift from God, than using those gifts in conjunction with my faith is not wrong at all, but is in fact very good! Notice, it is not an "either - or" option, but both. I believe that since I have used logic and reasoning in Christianity, my faith has grown in a way it never has before.
I have heard this said from several different Christian apologists, the most recent being Greg Koukl of Stand to Reason; "What I believe in my heart must also make sense in my head". How beautifully said. I can have all the faith in the world, and truly believe something is true, but if I refuse to employ logic and reason, what then is my source of objective truth? If all I am using for my standard is subjective feelings, then what makes my belief in Christianity any more valid than the Mormon's belief in Mormonism? If we are going by purely subjective feelings, why is it that the Mormons testimony they bear you that the Book of Mormon is true and that Joseph Smith was a true prophet, trumps my testimony which says that the Book of Mormon is false, Joseph Smith was a false prophet, and that Christianity is alone in the truth?
While I do not doubt the sincerity of belief or the passion behind a testimony, honestly, people from other faiths have amazing testimonies of their own faith. Why is a Muslims testimony any less valid than that of a Mormon if all we are measuring it by is faith? The answer is that there must be more. My believing Christianity is true is fine, but what if I am faced with evidence that stands in direct contradiction to my faith? What happens when the Mormon is shown that Joseph Smith was a false prophet? Does their desire to have him be a true prophet somehow overrule the truth? Perhaps in their heart it may, but it reality the answer is no.
Faith, reason, and logic all go together. It is through reason and logic we can look at arguments and test them to see if they are valid, or not. But simply making an emotional appeal to believe does not constitute evidence, or proof. When we look at the Bible, in particular the New Testament, we see people like Paul who was willing to reason with the unbelievers, not through emotional appeal alone, but through evidences, and reason. We see this happening when he corrected false teachings, such as baptism for the dead.
Lastly to keep in mind when responding to this argument, how exactly did the Mormon come to this conclusion? How did the Mormon come to the conclusion that faith and logic are not able to be used in conjunction with one another? Are they not using reason (be it flawed) to come to this conclusion? And I would encourage you to ask them that question by saying, "how did you come to that conclusion"? More than likely, you will hear them express their thoughts on the matter which would allude to them using both logic and reason to come to a conclusion. Again, this is self defeating.
So is it faith or reason? We as Christians who hold the standard of truth as the Bible can emphatically answer BOTH! It is through these God given gifts that we are able to recognize heresy and false teaching, along with the power of the Holy Spirit, and comparing all claims to the word of God, the Bible.
For more information on this topic, click HERE for an article from Stand to Reason