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Types of Knowledge: More Than Just Facts

When people hear the word knowledge, they often think of facts: dates, formulas, names, and statements that can be true or false. But knowledge is broader than that. It includes not only knowing that something is the case, but also knowing how to do something and knowing something through direct experience.

This broader picture matters because it changes how we think about intelligence, learning, and even what it means to understand the world. A person may know many facts about swimming and still not know how to swim. Someone may read pages about chocolate or a famous lake and still lack the first-hand familiarity that comes only from direct experience.

Propositional knowledge: knowing that

A major kind of knowledge is propositional knowledge, often called knowledge-that. It is knowledge of facts, such as knowing that 2 + 2 = 4 or knowing that kangaroos hop. It is called propositional because it involves a proposition, meaning a statement or content that can be true or false.

This is the type of knowledge that has often received the most attention in philosophy. It is commonly expressed using a that-clause, as in “I know that the baby is crying” or “she knows that gold has a certain atomic mass.” Propositional knowledge usually involves mental representations such as concepts, ideas, theories, and rules. These representations connect a knower to reality by showing what some part of the world is like.

Because of this reliance on concepts and representations, propositional knowledge is often associated with relatively sophisticated thinkers. It is not just raw contact with the world, but a grasp of facts in a form that can be stated, discussed, and evaluated.

Non-propositional knowledge: what facts alone cannot capture

Not all knowledge works like a fact in a sentence. Philosophers often group other forms under the label non-propositional knowledge. Two especially important forms are knowledge-how and knowledge by acquaintance.

These types do not essentially depend on standing in a relation to a proposition. In simpler terms, they are not mainly about holding a true statement in your mind. Instead, they involve practical competence or first-hand familiarity.

That is why knowledge is more than a mental storehouse of correct answers. It can also be a skill in action or a direct experiential connection.

Knowledge-how: skill, ability, and competence

Knowledge-how, also called know-how or procedural knowledge, is practical knowledge. It is the kind of knowledge involved in knowing how to ride a bicycle, how to swim, or how to perform some task successfully.

This form of knowledge is about ability, skill, or competence. In some cases, knowledge-how may involve knowledge-that. For example, proving a mathematical theorem may require grasping propositions and rules. But this is not true in general. A person or animal can possess a practical ability without being able to state a theory of what they are doing.

That point becomes especially vivid when we think about simple creatures. An ant knows how to walk, even though it presumably lacks a mind developed enough to represent the corresponding proposition. The example shows why knowledge-how cannot simply be reduced to storing sentences in the head. Many abilities do not require language-like thought.

This insight has a practical consequence: we often underestimate what counts as knowledge because we privilege what can be said out loud. But a great deal of competence is embedded in action rather than speech. Practical mastery may be hard to articulate even when it is real and reliable.

Knowledge by acquaintance: first-hand familiarity

Knowledge by acquaintance is different again. It is familiarity gained through direct experiential contact with a person, place, or thing. If you eat chocolate, you become acquainted with the taste of chocolate. If you visit Lake Taupō, you gain acquaintance with Lake Taupō.

This is first-hand knowledge, not knowledge derived by reasoning from other facts. The term non-inferential is useful here: it means known directly rather than inferred from premises. You do not reason your way into what chocolate tastes like in the same way you might infer that a friend is visiting the Czech Republic from a Czech stamp on a postcard. Instead, you encounter the object itself in experience.

This kind of knowledge explains an everyday difference people feel all the time. You can read books about a place, study a menu description, or memorize a chemical account of taste. But none of that guarantees the feel of direct familiarity. You may know many truths about chocolate while still not knowing its taste by acquaintance. You may know dozens of facts about a lake and still not know the lake in the way a visitor does.

That is why first-hand experience has a special role in learning. It adds a kind of contact that factual description alone cannot fully replace.

Why direct experience feels different

The contrast between factual information and acquaintance helps explain why some forms of learning feel thin while others feel vivid. Reading can give you descriptive knowledge. Observation can give you empirical knowledge. But acquaintance gives you immediate familiarity.

This does not mean factual knowledge is unimportant. In many cases, propositional knowledge travels farther and faster. It can be written down, stored in libraries, taught in lectures, and shared through testimony in speech, newspapers, letters, or blogs. By contrast, acquaintance often requires direct contact.

That directness is part of its power. It is grounded in experience itself rather than in a chain of reasoning or in another person’s report. This is why someone can be highly informed and still feel that they “don’t really know” something until they encounter it firsthand.

Bertrand Russell and the priority of acquaintance

The philosopher Bertrand Russell gave knowledge by acquaintance a particularly important place. He introduced the concept and argued that acquaintance is more basic than propositional knowledge.

His reasoning is strikingly simple: to understand a proposition, one must already be acquainted with its constituents. In other words, before a person can grasp a statement about something, there must already be some direct familiarity with the elements that make up that statement.

This gives acquaintance a foundational role in understanding. It is not merely one kind of knowledge among others, but a condition for making sense of at least some propositions at all. On this view, direct experiential contact is not an optional extra added after thought. It is woven into how thought gets a grip on reality.

Different kinds of knowledge, different ways of learning

Seeing these distinctions clearly can improve the way we think about education and expertise.

Explicit knowledge is knowledge that can be articulated, shared, and explained, like historical dates or mathematical formulas. It is often acquired through reading books or attending lectures. Tacit knowledge, by contrast, is not easily explained, such as recognizing a face or the practical expertise of a master craftsman. Tacit knowledge is often learned through first-hand experience or direct practice.

This maps neatly onto the contrast between knowing facts and knowing by skill or acquaintance. Some things are easy to write in a textbook. Others must be practiced. Still others must be encountered.

That is also why real understanding often uses multiple sources of knowledge. Perception gives access to the external world through the senses. Memory preserves what was learned in the past. Inference draws conclusions from what is already known. Testimony lets one person learn from another. But none of these entirely erases the special place of direct familiarity and embodied skill.

Why these distinctions matter

The difference between know-that, know-how, and acquaintance is not a technical quirk. It shapes debates about minds, education, and what counts as understanding.

If all knowledge were just propositions, then skill would seem secondary and experience would look like a mere delivery mechanism for facts. But practical ability and first-hand familiarity show that human knowledge is richer than that. A person can know without reciting a sentence, and can understand something more deeply through direct contact than through description alone.

This broader view also helps explain why some forms of knowledge are easier to communicate than others. Facts can often be transmitted through testimony and writing. Skills may require demonstration and practice. Acquaintance often demands experience itself.

So the next time someone treats knowledge as nothing but memorized information, it is worth remembering the larger landscape. We know truths, we know how, and we know through acquaintance. And without those latter forms, much of what makes knowledge feel real would be missing.