Could you tell me, what causes doubt, and unbelief, and how do I combat it?

Dear Gramps,
Could you please tell me, what causes doubt, and unbelief, and how do I combat it? My heart wants to, my head is saying all different things. I’m trying my best, can you help? I don’t wanna fail.
Mick, from Birmingham

Dear Mick,
Perhaps if we talked about a couple of principles it may help. The scientific method for gaining knowledge is based on the principle of doubt. In science we are not permitted to accept any postulate as true unless it has been proven by experiment or by logical deduction to be true. The religious method for gaining knowledge is quite the opposite. It is based on the principle of faith. We must accept the proposition as being true before the proof. We then put it into practice as though we knew it were true. If it is indeed true, it will be demonstrated to be so by our experience. As a result of that experience, we will know that it is true. Faith is acceptance before the fact; doubt is acceptance after the fact. Applying scientific principles to religious methodology never works.
So let’s take a case in point. Let’s say that a person wants to prove that the Book of Mormon is, as it claims to be, a true record containing the plan of life and salvation and the fullness of the gospel of Jesus Christ. The person could begin an investigation using the scientific method, examining the book from the many points of view that would be necessary to prove its authenticity. If he were objective in his research and unprejudiced, he could eventually come to a positive conclusion. On the other hand, using the religious method, the person could just act as though he knew it were true, read it with confidence, and act upon the principles that are announced therein. As he puts into practice each principle the Holy Ghost will confirm in his heart the truthfulness of the principle that he is practicing, and he will have a testimony given by the Holy Spirit, rather than the mere confidence of the scientific method, that he is in possession of the truth.
So if you have doubts and disbelief concerning any matter of religion, be objective about it. Use the religious methodology. Put it to the test. Try the experiment. As you do so you will find that it is indeed a practical approach, and your confidence in th application of faith will mount.

Now, as I said concerning faith–that it was not a perfect knowledge–even so it is with my words. Ye cannot know of their surety at first, unto perfection, any more than faith is a perfect knowledge. But behold, if ye will awake and arouse your faculties, even to an experiment upon my words, and exercise a particle of faith, yea, even if ye can no more than desire to believe, let this desire work in you, even until ye believe in a manner that ye can give place for a portion of my words. Now, we will compare the word unto a seed. Now, if ye give place, that a seed may be planted in your heart, behold, if it be a true seed, or a good seed, if ye do not cast it out by your unbelief, that ye will resist the Spirit of the Lord, behold, it will begin to swell within your breasts; and when you feel these swelling motions, ye will begin to say within yourselves–It must needs be that this is a good seed, or that the word is good, for it beginneth to enlarge my soul; yea, it beginneth to enlighten my understanding, yea, it beginneth to be delicious to me (Alma 32:26-28).

Gramps