Declarative knowledge
Declarative knowledge is an awareness of facts that can be expressed using declarative sentences. It is also called theoretical knowledge, descriptive knowledge, propositional knowledge, and knowledge-that. It is not restricted to one specific use or purpose and can be stored in books or on computers.
Epistemology is the main discipline studying declarative knowledge. Among other things, it studies the essential components of declarative knowledge. According to a traditionally influential view, it has three elements: it is a belief that is true and justified. As a belief, it is a subjective commitment to the accuracy of the believed claim while truth is an objective aspect. To be justified, a belief has to be rational by being based on good reasons. This means that mere guesses do not amount to knowledge even if they are true. In contemporary epistemology, additional or alternative components have been suggested. One proposal is that no contradicting evidence is present. Other suggestions are that the belief was caused by a reliable cognitive process and that the belief is infallible.
Types of declarative knowledge can be distinguished based on the source of knowledge, the type of claim that is known, and how certain the knowledge is. A central contrast is between a posteriori knowledge, which arises from experience, and a priori knowledge, which is grounded in pure rational reflection. Other classifications include domain-specific knowledge and general knowledge, knowledge of facts, concepts, and principles as well as explicit and implicit knowledge.
Declarative knowledge is often contrasted with practical knowledge and knowledge by acquaintance. Practical knowledge consists of skills, like knowing how to ride a horse. It is a form of non-intellectual knowledge since it does not need to involve true beliefs. Knowledge by acquaintance is a familiarity with something based on first-hand experience, like knowing the taste of chocolate. This familiarity can be present even if the person does not possess any factual information about the object. Some theorists also contrast declarative knowledge with conditional knowledge, prescriptive knowledge, structural knowledge, case knowledge, and strategic knowledge.
Declarative knowledge is required for various activities, such as labeling phenomena as well as describing and explaining them. It can guide the processes of problem-solving and decision-making. In many cases, its value is based on its usefulness in achieving one's goals. However, its usefulness is not always obvious and not all instances of declarative knowledge are valuable. Much knowledge taught at school is declarative knowledge. It is said to be stored as explicit memory and can be learned through rote memorization of isolated, singular, facts. But in many cases, it is advantageous to foster a deeper understanding that integrates the new information into wider structures and connects it to pre-existing knowledge. Sources of declarative knowledge are perception, introspection, memory, reasoning, and testimony.
Definition and semantic field
Declarative knowledge is an awareness or understanding of facts. It can be expressed through spoken and written language using declarative sentences and can thus be acquired through verbal communication. Examples of declarative knowledge are knowing "that Princess Diana died in 1997" or "that Goethe was 83 when he finished writing Faust". Declarative knowledge involves mental representations in the form of concepts, ideas, theories, and general rules. Through these representations, the person stands in a relationship to a particular aspect of reality by depicting what it is like. Declarative knowledge tends to be context-independent: it is not tied to any specific use and may be employed for many tasks. It includes a wide range of phenomena and encompasses knowledge of individual facts and of general laws. An example for individual facts is knowing that the atomic mass of gold is 196.97 u. Knowing that the color of leaves of some trees changes in autumn, on the other hand, belongs to general laws. Due to its verbal nature, declarative knowledge can be stored in media like books and harddisks. It may also be processed using computers and plays a key role in various forms of artificial intelligence, for example, in the knowledge base of expert systems.Terms like theoretical knowledge, descriptive knowledge, propositional knowledge, and knowledge-that are used as synonyms of declarative knowledge and express its different aspects. Theoretical knowledge is knowledge of what is the case, in the past, present, or future independent of a practical outlook concerning how to achieve a specific goal. Descriptive knowledge is knowledge that involves descriptions of actual or speculative objects, events, or concepts. Propositional knowledge asserts that a proposition or claim about the world is true. This is often expressed using a that-clause, as in "knowing that kangaroos hop" or "knowing that 2 + 2 = 4". For this reason, it is also referred to as knowledge-that. Declarative knowledge contrasts with non-declarative knowledge, which does not concern the explicit comprehension of factual information regarding the world. In this regard, practical knowledge in the form of skills and knowledge by acquaintance as a type of experiential familiarity are not forms of declarative knowledge. The main discipline investigating declarative knowledge is called epistemology. It tries to determine its nature, how it arises, what value it has, and what its limits are.
Components
A central issue in epistemology is to determine the components or essential features of declarative knowledge. This field of inquiry is called the analysis of knowledge. It aims to provide the conditions that are individually necessary and jointly sufficient for a state to amount to declarative knowledge. In this regard, it is similar to how a chemist breaks down a sample by identifying all the chemical elements composing it.A traditionally influential view states that declarative knowledge has three essential features: it is a belief that is true and justified. This position is referred to as the justified-true-belief theory of knowledge and is often seen as the standard view. This view faced significant criticism following a series of counterexamples given by Edmund Gettier in the latter half of the 20th century. In response, various alternative theories of the elements of declarative knowledge have been suggested. Some see justified true belief as a necessary condition that is not sufficient by itself and discuss additional components that are needed. Another response is to deny that justification is needed and seek a different component to replace it. Some theorists, like Timothy Williamson, reject the idea that declarative knowledge can be deconstructed into various constituent parts. They argue instead that it is a basic and unanalyzable epistemological state.
Belief
One commonly accepted component of knowledge is belief. In this sense, whoever knows that whales are animals automatically also believes that whales are animals. A belief is a mental state that affirms that something is the case. As an attitude toward a proposition, it belongs to the subjective side of knowledge. Some theorists, like Luis Villoro, distinguish between weak and strong beliefs. Having a weak belief implies that the person merely presumes that something is the case. They guess that the claim is probably correct while acknowledging at the same time that they might very well be mistaken about it. This contrasts with strong belief, which implies a substantial commitment to the believed claim. It involves certainty in the form of being sure about it. For declarative knowledge, this stronger sense of belief is relevant.A few epistemologists, like Katalin Farkas, claim that, at least in some cases, knowledge is not a form of belief but a different type of mental state. One argument for this position is based on statements like "I don't believe it, I know it", which may be used to express that the person is very certain and has good reason to affirm this claim. However, this argument is not generally accepted since knowing something does not imply that the person disbelieves the claim. A further explanation is to hold that this statement is a linguistic tool to emphasize that the person is well-informed. In this regard, it only denies that a weak belief exists without rejecting that a stronger form of belief is involved.
Truth
Beliefs are either true or false depending on whether they accurately represent reality. Truth is usually seen as one of the essential components of knowledge. This means that it is impossible to know a claim that is false. For example, it is possible to believe that Hillary Clinton won the 2016 US Presidential election but nobody can know it because this event did not occur. That a proposition is true does not imply that it is common knowledge, that an irrefutable proof exists, or that someone is thinking about it. Instead, it only means that it presents things as they are. For example, when flipping a coin, it may be true that it will land heads even if it is not possible to predict this with certainty. Truth is an objective factor of knowledge that goes beyond the mental sphere of belief since it usually depends on what the world outside the person's mind is like.Some epistemologists hold that there are at least some forms of knowledge that do not require truth. For example, Joseph Thomas Tolliver argues that some mental states amount to knowledge only because of the causes and effects they have. This is the case even if they do not represent anything and are therefore neither true nor false. A different outlook is found in the field of the anthropology of knowledge, which studies how knowledge is acquired, stored, retrieved, and communicated. In this discipline, knowledge is often understood in a very wide sense that is roughly equivalent to understanding and culture. In this regard, the main interest is usually about how people ascribe truth values to meaning-contents, like when affirming an assertion, independent of whether this assertion is true or false. Despite these positions, it is widely accepted in epistemology that truth is an essential component of declarative knowledge.