Dear Theophilus: How Can I Know What Is True?

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Dear Faculty,

What is the difference belief and knowledge? How can I know what I believe is true?


Dear Theophilus,

That is a great question. I am glad you are asking it. There are a couple of things implied in your question⁠—whether you meant it or not⁠—that go against many of our current cultural assumptions. First, you believe there is a truth to know. Second, you hold out the possibility of knowledge.

Often, in the time and place in which we live, people do not believe there is any truth beyond our personal opinions and they do not believe there is a possibility of knowing. So, your question cuts across the grain of the general skepticism and apathy of our culture.

A Truth to Know

To begin, I want to affirm and clarify what you have assumed in your question. That is, there is a truth to know. All we are recognizing here is that there is a reality that is distinct from our beliefs about it. Things are or are not a certain way whether we believe it or not.

When we use the word truth or true, we are saying that what we believe or say about reality actually aligns with reality. So, if something is so and I believe or say it is so, then what I believe or say is true. If something is not so and I believe or say it is so, then what I believe or say is false.

It may seem a little elementary to clear this up, but if we do not agree that our beliefs can be true or false, then we will not be motivated to pursue what is true. We will not care about the second question.

Belief, Opinion and Knowledge

If we assume that our beliefs can be true or false, then we can turn to the heart of your question, which is: how can we know? To answer this, I want to briefly define what we mean by beliefs, opinions and knowledge. Our beliefs are our conscious or unconscious thoughts about reality. These thoughts may be spoken or unspoken. They may be consciously held or just assumed. Most importantly, they can be true or false based on whether they correspond with reality.

Most people use the word belief to mean opinion and they put belief in the category of the unprovable, unfalsifiable and unknowable. This is not quite right. I would like you to think about opinion and knowledge as two different categories of beliefs. That is, knowledge is when we have a true belief with adequate grounds. We may say opinions are beliefs without grounds.

Knowledge is belief; however, knowledge is the term we use when there is enough reason or justification for a belief to be taken as true. Knowledge must be true. We do not use the term knowledge for beliefs that are false. We do not use the term for those things that we do not have adequate evidence or grounds to take as true.

Opinions, on the other hand, are beliefs that we do not have enough reason or justification. Opinions can still be true or false unless they are simply a matter of taste (like our preferences for certain foods). However, we may use the term to describe beliefs we hold based on feelings or those beliefs for which there is not enough evidence or reason to know what is true.

Three Paths to Knowledge

We can now address the question directly: how can we know if our beliefs are true? We have already established that our goal is to have true beliefs and that our beliefs become knowledge when there are adequate reason or justification. There are three main paths that we can take.

Reason – As human beings, we possess the faculty of reason. We can evaluate beliefs and their grounds through logical analysis. This assumes that something true will not be irrational or incoherent. However, it is possible to have logical arguments that are not grounded in reality. They are logically-valid but not true. So we need another tool to work with reason.

Evidence – We live in an orderly world where we can observe the evidence and draw conclusions from the evidence. Assumed is that something true would not be in complete contradiction with the observable world. We cannot observe everything, however and all evidence must be interpreted. So, evidence cannot stand on its own without the help of the other two paths.

Ethics/Practice – This path cannot stand on its own, but it can be a helpful way to evaluate certain beliefs. In this case, we think about the ethical or practical implications of a belief. Essentially, we ask, “If someone lived this out, what kind of life would it lead to?” This assumes that a true belief would not be completely out of step with our moral intuition.

I happen to think that none of them can stand on their own, but all of them—when used together—move us toward that “adequate grounds” to confirm whether a belief is true. If reason, evidence and ethics all start to point in one direction, we can grow in our confidence that it is true.

I hope this helps. Continue to search for the truth!

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The views and opinions expressed in this article are those of the author’s and do not necessarily reflect the official policy or position of Grand Canyon University. Any sources cited were accurate as of the publish date.


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