What Aquinas Meant by “No Explanation Is Necessary”

Quote Analysis

When Thomas Aquinas famously said:

“To one who has faith, no explanation is necessary. To one without faith, no explanation is possible,”

he wasn’t dismissing reason—he was drawing a line between two fundamentally different ways of understanding the world. In an age obsessed with evidence, logic, and explanation, his words challenge us to consider: Can faith exist independently of rational proof? And if so, is it even communicable to those who have never experienced it? n this article, we explore the deeper meaning of Aquinas’ quote, its philosophical context, and what it tells us about knowledge, belief, and the human condition.

The Meaning of the Quote: Faith as the Boundary of Reason

Thomas Aquinas’ quote, “To one who has faith, no explanation is necessary. To one without faith, no explanation is possible,” communicates a profound idea: faith operates outside the normal domain of rational argument. This does not mean that faith is irrational—but rather, that it functions on a different level of understanding.

Think of it this way: If someone has had a powerful personal experience—like falling in love or witnessing a miracle—they often don’t need an external justification. They know what they know, not because someone proved it to them, but because they lived it. That’s what Aquinas is pointing at. For the faithful, belief comes from an inner conviction that doesn’t rely on logical proofs.

On the other hand, someone who has not experienced that inner certainty may not be moved by arguments, no matter how well-constructed they are. It’s like trying to explain the taste of honey to someone who has never tasted sweetness—words alone don’t do it justice. In this sense, faith is not just a belief; it’s a form of perception, one that logic can’t fully reach.

This quote reminds us that human understanding doesn’t come only through deduction and evidence. There are also experiential ways of knowing—and faith, for Aquinas, is one of the highest.

Context in Aquinas’ Thought: Faith and Reason as Distinct but Harmonious

To fully grasp what Aquinas meant, we need to understand the intellectual world he lived in. Thomas Aquinas was a 13th-century Dominican friar, philosopher, and theologian who tried to harmonize two powerful systems: Christian theology and Aristotelian philosophy. In his view, faith and reason were not enemies, but partners—each with its own scope and method.

According to Aquinas, reason is the tool we use to understand the natural world and to explore truths that are within human reach. It is through reason that we build science, philosophy, and ethical systems. Faith, however, is the means by which we access divine truths that go beyond human comprehension—things like the mystery of the Trinity, the Incarnation, or the promise of eternal life.

He made a crucial distinction between:

Truths that reason can discover on its own (e.g., that God exists),
and truths that require divine revelation (e.g., that God is triune).

Thus, when Aquinas says no explanation is possible for the one without faith, he doesn’t mean we should give up on dialogue. What he means is that faith-dependent truths require a disposition of openness and humility, not just intellect. Without that openness, no philosophical argument will be enough.

So, in Aquinas’ thought, faith is not blind—it is supra-rational. It begins where reason reaches its limit and trusts in truths revealed by a higher source. His quote reflects this framework: logic and faith aren’t opposed, but they operate in different domains. And when it comes to faith, no amount of logic will ever substitute for the inner act of believing.

The Epistemological Message: Knowledge That Can’t Be Transferred Through Logic

At the heart of Aquinas’ quote is a deep epistemological insight—that is, a statement about the nature and limits of knowledge. He’s telling us that some forms of understanding are not transferable through rational explanation alone. This might sound abstract, but let’s break it down.

When we think about knowledge, we often imagine facts, data, or logical arguments. For example:

2 + 2 = 4
Water boils at 100°C
The earth orbits the sun

These are propositional truths—they can be explained, tested, and proven. But there’s another kind of knowing, which philosophers sometimes call experiential or existential knowledge. This type isn’t always easy to describe or justify. Faith, according to Aquinas, belongs to this second category.

Let’s take an analogy. Imagine trying to explain what it’s like to hear a beautiful piece of music to someone who is deaf. You can describe the instruments, tempo, and lyrics. You can even show them how others react. But in the end, unless they hear the music themselves, they won’t truly understand it. That’s what Aquinas is pointing to: faith is a kind of inner hearing, a spiritual perception, not a mathematical formula.

Philosophers like Søren Kierkegaard and Ludwig Wittgenstein also touched on this problem. They argued that some human experiences—faith, love, grief, awe—can’t be fully expressed in logical language. They require participation, not just observation.

So, the quote teaches us something important about communication and knowledge: Not everything can be taught through argument. Some truths must be lived to be understood. And without that lived dimension, even the clearest explanation may fall flat.

Possible Criticisms and Modern Interpretations

While many find Aquinas’ quote profound, it has also drawn criticism—especially in modern secular and scientific circles. Let’s look at some of these critiques and how contemporary thinkers interpret the quote today.

One common criticism is that the quote may discourage intellectual inquiry. By saying that no explanation is possible for the unbeliever, some argue that it sounds like giving up on dialogue or rational persuasion. In the wrong hands, the quote could even be misused to justify blind belief or dogmatism.

Others see the quote as suggesting that faith is irrational, or that it’s disconnected from reason entirely. This is a misunderstanding of Aquinas, but it’s a concern especially among those who prioritize scientific thinking, evidence, and debate.

Let’s clarify something: Aquinas never said that faith is against reason. He believed that reason is essential—but also limited. In his framework:

Reason leads us toward truth.
Faith completes the picture where reason alone can’t reach.

Modern interpreters often use this quote to reflect on the limits of scientific rationalism. Science is powerful, but it doesn’t answer every question—like “What is the meaning of life?” or “Why should we care about justice?” For such questions, other forms of understanding (like philosophy, art, and yes, faith) come into play.

Contemporary thinkers like Alasdair MacIntyre or Charles Taylor defend the idea that faith is not irrational, but rooted in a different kind of rationality—a broader vision of what it means to live well, love deeply, and act ethically.

So, rather than seeing Aquinas’ quote as a wall between believers and skeptics, modern interpreters often see it as an invitation: an acknowledgment that some truths require more than arguments—they require a shift in perspective.

Related Philosophical Ideas and Comparisons

Thomas Aquinas’ statement about faith not needing explanation has parallels in other philosophical and religious traditions. Although each thinker comes from a unique context, many have touched on the inexpressibility of deep personal truths and the limits of logic when it comes to spiritual understanding.

Let’s look at a few relevant comparisons:

Blaise Pascal, a 17th-century French philosopher, argued that the heart has its reasons which reason does not know. His famous wager didn’t aim to prove God exists through logic, but rather to show why belief can be a rational choice—even in the absence of certainty.
Søren Kierkegaard, often called the father of existentialism, introduced the concept of the leap of faith. For him, true faith begins where reason ends. Belief is not the result of logical deduction—it’s a courageous personal decision that often goes against common sense.
Alvin Plantinga, a contemporary philosopher, developed the idea of properly basic beliefs—beliefs like trust or love that are rational, even if they’re not based on evidence. For him, belief in God can be one such foundational belief that doesn’t need to be argued from scratch.
In Eastern traditions, such as Buddhism or certain forms of Hinduism, insight or awakening is also described as something beyond words. The Zen Buddhist concept of satori (sudden enlightenment) cannot be explained—it must be experienced directly, often after long silence or paradox.

What connects all these perspectives is the idea that some truths are known by participation, not explanation. Aquinas’ quote fits into this wider tradition. It’s not about rejecting logic—it’s about recognizing that logic has limits, and that personal transformation often begins beyond those limits.

The Ethics of Belief: Is Faith a Matter of Will or Evidence?

One final question arises from Aquinas’ statement, and it’s both philosophical and deeply personal: Is faith something we choose, or something we receive? In other words, can a person simply decide to believe, or does faith come as a kind of gift—something that happens to us?

This question has been explored by many thinkers, especially in the area known as the ethics of belief—a branch of philosophy that asks whether we are morally responsible for what we believe.

Let’s break down the two major views:

William James, the American pragmatist, argued in The Will to Believe that in certain cases—especially those involving moral or existential questions—it is okay to believe even if the evidence is incomplete. He said that in some situations, waiting for proof might mean losing the chance for truth. For example, if you wait for scientific proof that someone loves you, you might miss the love itself.
W.K. Clifford, on the other hand, took the opposite stance. He believed that it is always wrong to believe something on insufficient evidence. According to him, faith without proof is intellectually irresponsible.

Aquinas’ view falls somewhere in between. He does not reject reason or evidence—but he believes that faith ultimately goes beyond them. For him, belief is not just a conclusion; it’s a movement of the will, guided by grace. That means:

Faith involves freedom, but not pure willpower.
It’s not blind, but also not provable in the scientific sense.
It’s something you can’t force, but you can be open to.

So, the ethical question is not, “Should you believe without proof?” but rather, “Are you willing to open yourself to something that cannot be fully explained?” Aquinas challenges us not to abandon reason, but to recognize when it’s time to move from thinking to trusting.

“To One Who Has Faith, No Explanation Is Necessary” – What Thomas Aquinas Meant About the Limits of Reason