One of the most important principles to critical thinking, open-mindedness, and fruitful ideological discussions is that truth and conviction are two different things.
Just because you are convinced of a belief does not make it true, nor does it mean that others must accept it to be true. And even if the belief is true, others have to be convinced that it is before they embrace it.
Critical thinking does not bother too much about whether a conclusion is true or not, but looks at how a thinker arrived at their conclusion. Was the conclusion reached through independent inquiry (as opposed to confirmation biases), a consideration of facts (as opposed to assumptions and inherited beliefs), and rational reasoning (as opposed to rationalizations and logical fallacies)?
If the facts and reasoning are sound, they will take care of the conclusion. But a healthy mind needs to consider facts and connect them through reason to arrive at a conclusion. Without the foundations, a conclusion is simply an assertion. It makes a claim about reality without offering any evidence.
For you to share your convictions with others, they must be exposed to the reasoning you used to arrive at these convictions. Only then can they properly consider your beliefs and whether they can accept them to be true or not.
Human beings don’t think in a vacuum. Any person you have a discussion with will have formed an impression of what the truth is. This is largely influenced by religion and culture (to varying degrees, depending on one’s society and upbringing). For you to effectively communicate your beliefs with others, you have to take their existing beliefs into consideration, and to build your line of reasoning from their current beliefs to yours, in a way that is logical and relevant to their thinking.
I’m always baffled by those who seek to convince others of the truth of their religion by simply quoting their scriptures. They assume that exposure to scripture alone is sufficient in cultivating conviction. And what’s more troubling is the fact that – in most cases – they have never stopped to question their own convictions and how they arrived at them. The vast majority of religious people live their lives with the convictions of their parents, and the beliefs they were taught through their upbringing.
They grow up to assume that their sense of certainty (largely formed as a bubble of ignorance of other beliefs and perspectives) is self-evident or blatantly obvious that no one can deny it, unless they’re intentionally (and cunningly) rejecting the truth. They fail to accept the nature of conviction, how it is formed, and how the truth is different to what we experience as certainty.
It is a sad fact that many people do not care about the truth, even if they preach to others about embracing it. They are simply comfortable with their own convictions and want to experience certainty, rather than live in doubt.
A freethinker is comfortable in admitting the limits of his or her knowledge, is not afraid of experiencing doubt, and knows that whatever convictions he or she currently hold are only attempts at arriving at the truth. They remain open to sharing their ideas and listening to what others have to share.