There is a certain sort of ideology which views belief as a fully conscious choice. That is to say, there are those who believe that a person could potentially wake up one morning and make the fully conscious choice to believe that elephants can fly (should it suit their fancy to believe such a thing). Belief, in this view, is as much a choice as deciding what clothes to wear.
I’ll leave the whole “free will vs. determinism” debate at the door; it complicates the terminology, and in this scenario we’re only talking about whether belief is a conscious mechanism. That is to say, we’re talking about whether the act of believing in information presented by another person is a simple decision.
Take a moment, and try to believe something for which you have no precedent to believe. You could try my earlier elephant example, or you could come up with something else. Either way, it must be something that does not already exist within your worldview. Can you do it? Is it easy? Or do you still know, on some level, why it doesn’t mesh with your reality?
When I used the words “your reality”, I am not, of course, embracing some sort of subjectivist New Age philosophy. I believe that objective reality exists, even if not all aspects of reality are easily comprehensible. When I say “your reality”, I’m talking about your internal model of the way the world works. I’m talking about the way you rationalize and support the things you believe. You might rationalize your attraction to the ground by invoking the well-documented concept of gravity. You probably base your views about personal success on the priorities you have developed over the course of your life. You support your religious beliefs (if you have them) with religious education and personal experiences.
All of this represents a large, complex intellectual infrastructure which composes and supports your view of the world. Lack the intellectual infrastructure necessary to believe in something, and you’ll find that it is very difficult to convince yourself to “just believe”. Conversely, if you possess the intellectual infrastructure supporting a particular belief, you’ll find that it is very difficult to simply throw that belief away. It is for these reasons that altering a deeply-entrenched belief is often a long, arduous, and only partially-voluntary process.
Example: 9/11 Truther Conspiracies. What sorts of things would you already need to believe if you wanted to believe in a 9/11 conspiracy? Well, first, you would need to believe that the government, for all of its bureaucratic incompetence, is capable of planning an attack on America in perfect secrecy. You’d need to disbelieve the overwhelming evidence that radical Islamists and political dissidents perpetrated the attack. You’d need to believe that the government was capable of perfectly coordinating its response to make it appear that they were just as surprised as we were. You’d need to believe that the extensive evidence in the 9/11 Commission Report, written and reviewed by hundreds of independent experts, was fake. Do you see what it takes to believe such a thing? Your entire worldview must be very well-coordinated, while simultaneously ignoring all opposing evidence.
Belief is not a trivial act. It’s act that requires an entire complementary worldview. People don’t believe (or disbelieve) ideas because they want to; they believe (or disbelieve) ideas on the basis of having (or not having) the intellectual infrastructure necessary to support the ideas. Certainly it is true that emotions and personal preferences play into belief, but liking or disliking an idea tends to only manifest as confirmation bias. That is to say, the like or dislike of an idea tends to make it easier to cement acceptance of an already-believed notion, deny an already-disbelieved notion, or seed doubt in a shaky belief. Preference alone does not change belief. It simply makes you more (or less) amenable to belief.
No doubt that the religious would like to believe that we could all choose belief in their respective religions if we just made the choice to accept their god(s). No doubt that conspiracy theorists would like the believe that the evidence is all obvious, man, you just have to accept it and draw the obvious conclusion! No doubt that scientists would like the believe that scientific concepts are universally (and easily) acceptable notions, for the same reasons as the conspiracy theorist. But none of this true. Until we all understand the psychological complexity of belief, we won’t be able to properly persuade others about controversial issues (or understand why they refuse to believe) without a great deal of frustration and argument.