What is interesting to me is how often one will hear about how fragile testimonies can be. Statements in General Conference or Sacrament Meetings will often remark about a testimony needs to be constantly “nourished” through scripture reading, church attendance, and by bearing of the testimony (“witnessing” in traditional Christian parlance). A related analogy that I heard was that having a testimony was like swimming upstream in a river - we need to be constantly working because if we’re not doing anything we’ll go downstream.
Here’s the thing: if it’s a real “testimony,” why should it NEED strengthening? For example, I know I live in Ogden, UT. I can bear testimony to that (in the court sense). I don’t have to wake up every so often and recite it to an individual (or a congregation) to convince myself of that fact. Just like I don’t have to keep convincing myself that concrete is hard. Or that the Pythagorean Theorem works. In the court sense, a witness shouldn't need to wake up every morning and reaffirm that it was the blue car that ran the red light and caused the accident.

Allow me to illustrate how this looks to me with a little analogy. It seems like people trying to convince themselves that Santa is real (sorry, it’s just after Christmastime, and it was an easy target). For most of them, they have been told that Santa was real ever since they were little. And they were told to just keep convincing themselves and their friends of that fact, despite mounds of evidence to the contrary. To wit:

2. The North Pole workshop doesn't appear on maps.
3. There are differing accounts on the personality and physical description of Santa depending on what culture one is from
4. The physics behind delivering so many toys to so many kids worldwide is impossible
5. Et cetera.
Despite statements like these, kids have been able to put them out of their minds and ignore evidence and keep their convictions that Santa is real. After all, believing in Santa just feels good. And let’s face it, for the most part, belief in Santa is pretty benign and can be fun. But we all know some people who go WAAAY too far with the whole Santa thing.
Ok, I think you get my point, so we’ll drop the Santa analogy. What I’m getting to is that rational people will drop the belief once they learn the real facts about how it was really their parents all along. That does, after all, make a lot more logical sense. But here’s where things get a little different in the real world. When confronted with facts that contradict belief, instead of changing beliefs, Mormons tend to dig in deeper (though this practice is not limited to Mormons). Instead of having faith that acts as a bridge between belief and fact, Mormons re-define faith as a shield against uncomfortable facts and history and choose to ignore them.
The traditional defense against science and logic used by Mormons is that they experienced the “burning bosom” of the Holy Ghost telling them that what they learned in church was true. Often, they add that they can’t deny what they felt, and that it trumps any facts that contradict what they felt.
But as it turns out, the LDS religion isn't the only one to make people have good feelings and emotions to swell (it’s also possible to duplicate the feeling using certain meditation techniques). In fact, just a little research from the web will confirm that there are many people around the world who feel the exact same feelings about their religions. Why are their accounts and “testimonies” not just as valid as any Latter-day Saint’s?

Unfortunately, feelings can’t always be trusted. I felt good feelings while hearing one of the stories behind Del Parson’s most famous painting. I loved that story . . . that is, until I heard it from Del Parson himself at a talk that it was completely false. I was confused and wasn't sure what to think about it (I was experiencing what is called cognitive dissonance). So I guess that’s why the Scientific Method was invented.

I'll end this with three quotes from past General Authorities.
#1: If a faith will not bear to be investigated; if its preachers and professors are afraid to have it examined, their foundation must be very weak. (Journal of Discourses, Volume 14, Page 216)
- George Albert Smith, LDS Church President
- LDS Apostle Hugh B. Brown, “A Final Testimony,” from An Abundant Life, 1999
#3: "If we have the truth, it cannot be harmed by
investigation. If we have not the truth, it ought to be harmed."
- J. Reuben Clark, LDS Presidency First Counselor
- J. Reuben Clark, LDS Presidency First Counselor
(authored by Joseph using Anne's blogger account)