The Epistemological Lifeboat

Epistemology and Philosophy of Science for Information Scientists

Birger Hjørland & Jeppe Nicolaisen (eds.)

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One meaning of the word rationalism is that reason, as opposed to irrationalism or authoritanism plays (or should play) a dominant role in our attempt to gain knowledge. To fail to employ reason is to form beliefs on the basis of such non-rational processes as blind faith, guessing or unthinking or obedience to institutional authority. This is a weak form of rationalism. This view is clearly not very controversial and thus widely accepted. Scholars of the Enlightenment generally had in mind something like this: a general confidence in the powers of the human intellect, in opposition to faith and blind acceptance of institutional authority, as a source of knowledge when they refer to the rationalist spirit of the period and the work of such philosophers as Voltaire (1694-1778).

In a more narrow sense is rationalism the epistemological doctrine that reason as opposed to experience (empiricism) is the most important source of knowledge. This view takes reason to be a distinct faculty of knowledge distinguished from, in particular, sense experience. To employ reason is to grasp self-evident truths or to deduce additional conclusions from them. This is a much stronger version of rationalism which asserts that the intellectual grasp of self-evident truths and the deduction of ones that are not self-evident is the major source of knowledge beyond even the slightest doubt. Clearly it is much more controversial and not widely accepted.

Rationalism in this second sense has roots back to Plato but is especially associated with the seventeenth and eighteenth centuries in the history of philosophy leading up to Kant. The major philosophers of this period are regularly grouped into two sets of three: Descartes, Spinoza and Leibniz are the Continental Rationalists, in opposition to Locke, Berkeley and Hume, the British Empiricists. This classification is not without problems. Philosophers in each group mutually differ very much, and there are also important agreements crossing these classes. 

Among the core metaphysical assumptions ascribed to rationalism is the idea of innate ideas and concepts (in contrast to the “tabula rasa” of the empiricists). The basic rationalist argument is that we cannot use empirical data unless we have already some concepts and categories to discriminate the data. When investigating a topic, the rationalist emphases to organise the knowledge in systems of axioms, definitions and theorems. Geometry was seen as the ideal science by many rationalists, as a proof that it is possible to build valuable and genuine knowledge without using any empirical data. A major blow for rationalism was thus the development of non-Euclidian geometry, which challenged some basic intuitions on which it had relied. In the 20th Century, the development of cognitivism represented a kind of rationalistic turn. 

In knowledge organization the rationalist view implies that all concepts can be ordered in a system, in which each concept has a definite place. There is no relativism due to specific applications or points of view. Hjørland (1997) found the system of Ranganathan to be a model of the rationalist view in information science.

Basic Principles in Classical Rationalism
(from Hjørland, 1997)

  • It is possible to formulate the basic principles on how to obtain knowledge.

  • Knowledge consists of elements (facts, modules) of infallible knowledge. The elements can be combined to larger units. Therefore, in principle, knowledge is modular.

  • Knowledge is infallible.

  • Besides the pure logical principles - other general principles exists.

  • Pure and isolated experience provides no knowledge. You have to carry aiding hypotheses or other fundamental assumptions in the luggage

  • In every domain of knowledge, it is possible to organize the knowledge in axioms, definitions and theorems.

  • It is the thinking of the separate individual human being and the sense of evidence, which forms the basis for the attainment of knowledge (methodological individualism)

  • Simple (non-defined) concepts are concepts which cannot be defined from other concepts in interesting ways

  • Fundamental concepts are concepts which are indispensable to describe or explain a topic.

  • Simple and fundamental concepts enter into some necessary relations to each other. These relations reflects basic principles of reason.

  • The analysis of a arbitrary topic leads to a number of simple and fundamental concepts.

  • Every concept can be organized in an all-embracing structure of concepts.

  • The difference between simple and compound concepts is absolute. It is not just the case, that something is simple and something is compound when seen from a certain point of view (knowledge interest) or in a certain respect.

  • Empirical experience can be used to check ideas on general connections. However, it is never decisive for the insight in these.

  • You can never determine the content of a concept by the presentation of examples of that concept. On the contrary: every sensory recognition presupposes that the perceiving person already has certain concepts ("carries something in the luggage")

  • An analytical statement is a statement, whose truth-value is logically established. To a rationalist, there exist necessary statements, which are not analytical. However, to an empiricist there is no necessity in the world, everything that happens is contingent.

  • The predisposition to realize basic concepts that does not originate from experience must be inborn. It is our way to form concepts, which determines the essential connections between the things, we can learn


Hjørland, B. (1997): Information Seeking and Subject Representation. An Activity-theoretical approach to Information Science. Westport & London: Greenwood Press. 

Hjørland, B. (2005). Empiricism, rationalism and positivism in library and information science. Journal of Documentation, 61(1), 130-155. Available at:

Markie, P. J. (1998). Rationalism. IN: Routledge Encyclopedia of Philosophy, Version 1.0, London: Routledge


Entry added: February 16, 2005
Last update: January 19, 2007