Reason

In western philosophy, reason has had a twofold history. On the one hand, it has been taken to be objective and so to be fixed and discoverable by dialectic, analysis or study. Such objectivity is the case in the thinking of Plato, Aristotle, Aquinas, Maimonides, al-Farabi and Hegel. In the vision of these thinkers, reason is divine or at least has divine attributes. Such an approach compelled religious philosophers--Aquinas, for example, Gilson more recently--to square reason with revelation, no easy task.

On the other hand, since the seventeenth century rationalists, reason has been taken to be a subjective faculty, or rather the unaided ability (eg., pure reason) to form concepts. For Descartes, Spinoza and Leibniz, the effort resulted in significant developments in mathematics. For Kant, in contrast, pure reason was shown to have the ability to form concepts (time and space) that are the conditions of experience. Kant made his argument in opposition to Hume, who denied that reason had any role to play in experience.

Discussion about reason especially concerns:
 * (a) its relationship to several other related concepts: language, logic, consciousness etc,
 * (b) its ability to help people decide what is true, and
 * (c) its origin.

Also see practical reason and speculative reason.

The concept of reason is connected to the concept of language, as reflected in the meanings of the Greek word "logos", later to be translated by Latin "ratio" and then French "raison", from which the English word derived. As reason, rationality, and logic are all associated with the ability of the human mind to predict effects as based upon presumed causes, the word "reason" also denotes a ground or basis for a particular argument, and hence is used synonymously with the word "cause".

Reason and logic
While reason is a type of thought, logic is a field of study which describes ways of reaching conclusions that are in accordance with reason. This contrast between reason and logic thus extends back to the writings of Aristotle. Although the Greeks had no separate word for logic as opposed to language and reason, Aristotle's neologism "syllogism" (syllogismos) identified logic clearly for the first time as a distinct field of study. (When Aristotle referred to "the logical" the source of our word "logic" he was referring more broadly to reason or the rational.)

Reason and logic can be thought to be distinct, although logic is one important aspect of reason. But the tendency to a preference for "hard logic," or "solid logic," in modern times has incorrectly led to the two terms occasionally being seen as essentially synonymous (see Reasoning) or perhaps more often logic is seen as the defining and pure form of reason.

However machines and animals can unconsciously perform logical operations, and many animals (including humans) can unconsciously associate different perceptions as causes and effects and then make decisions or even plans. Therefore, to have any distinct meaning at all, “reason” must be the type of thinking which links language, consciousness and logic, and at this time, only humans are known to combine these things.

Although this is an old discussion, the neurologist Terrence Deacon, following the tradition of Peirce, has recently given a useful new description in modern terms. Like many philosophers in the English traditions such as Hobbes, Locke and Hume, he starts by distinguishing the type of thinking which is most essential to human rational thinking as a type of associative thinking. Reason by his account therefore requires associating perceptions in a way which may be arbitrary (or nominal, conventional or "formal") - not just associating the image or "icon" of smoke and the image of fire, but, for example, the image of smoke and the English word "smoke", or indeed any made-up symbol (not necessarily a spoken word). What is essentially rational, or at least essentially human, is however not the arbitrariness of symbols, but how they are used. See below concerning Reason and Language.

Reason, truth, and “first principles”
Already in classical times a conflict between the Platonists and the Aristotelians developed about reason's role in confirming truth. Both Aristotle and Plato were aware of this as a question all philosophy must consider. On the one hand people use logical syllogisms such as deduction and induction in order to come to conclusions they feel are more infallible than our basic sense perceptions. On the other hand, if such conclusions are only built upon sense perceptions, then our most logical conclusions can never be said to be certain because they are built upon fallible perceptions (or fallible interpretations of perceptions). So given the impression that we are sometimes certain, as well as the desire to be certain, the question arises as to the source of our first principles. Is it only experience as claimed in “empiricist” arguments (associated by some as being more Aristotelian, and more recently with British philosophers such as David Hume); or is there some other “faculty” from which we derive our consciousness of at least some “a priori” truths (a position called “idealist” and associated with Platonism); or are there (as supported by the Scottish School of Common Sense, exemplified by Thomas Reid, and more recently by Objectivism) certain undeniable axioms that form the base for all other faculties of experiences?

In Greek, “first principles” are arkhai, starting points, and the faculty used to perceive them is sometimes referred to in Aristotle and Plato as “nous” which was close in meaning to “awareness” and therefore “consciousness”. This leaves open the question of whether we become aware by building up and comparing experiences, or some other way.

Modern proponents of a priori reasoning, at least with regards to language, are Noam Chomsky and Steven Pinker, to whom Merlin Donald and Terrence Deacon can be very usefully contrasted.

Reason, language and mimesis
The recent writings of Deacon and Donald fit into an older tradition which makes reason connected to language, and mimesis, but more specifically the ability to create language as part of an internal modelling of reality specific to humankind. Other results are consciousness, and imagination or fantasy.

Thomas Hobbes describes the creation of “Markes, or Notes of remembrance” (Leviathan Ch.4) as “speech” (allowing by his definition that it is not necessarily a means of communication or speech in the normal sense; he was presumably thinking of "speech" as an English version of "logos" in this description). In the context of a language, these marks or notes are called "Signes" by Hobbes.

David Hume, following John Locke (and Berkeley), who followed Hobbes, emphasized the importance of associative thinking.

Concerning mimesis and fantasy being important in defining reason, see for example Aristotle's Poetics, De Anima, On Dreams, and On Memory and Recollection (and for example the Introduction by Michael Davis, printed with the 2002 translation by him and Seth Benardete of the Poetics), Jacob Klein’s A Commentary on the Meno Ch.5, and Tolkien's essay "On Fairy Stories".

Reason and emotion or passion
In literature, reason is often opposed to emotions or feelings, and desires, drives or passions. Others see reason as the servant or tool of these things -- the means of sorting out our desires and then getting what we want. Some would say however that many of the key philosophers of history (e.g. Plato, Rousseau, Hume, Nietzsche) have combined both views - making rational thinking not only a tool of desires, but also something which is itself desired, not only because of its usefulness in satisfying other desires.

At the same time, reason sometimes seems to come into conflict with some desires (even while not being in conflict with others) that, at the very least, ceratain emotions are separate from reason. Only in humans, choices are sometimes made on the basis of an association of ideas which is an artificially constructed model, rather than an un-inspected association based on raw experience, and this “feels” different from when one is won over by a passion supported solely by intuition. The opposite is also unique – we sometimes feel that a passion has won over our decision-making “unjustly”, despite having lost its argument, or perhaps not even having been a subject of argument before the action took place.

Modern psychology has much to say on the role of emotions in belief formation. Deeper philosophical questions about the relation between belief and reality are studied in the field of epistemology, which forms part of the philosophical basis of science, a branch of human activity that specifically aims to determine (certain types of) truth that are not dependent on the emotions of the researchers.

Reason and faith, especially in the “Greater West”
In theology, reason, as distinguished from faith, is the human critical faculty exercised upon religious truth whether by way of discovery or by way of explanation. Some commentators have claimed that Western civilization can be almost defined by its serious testing of the limits of tension between “unaided” reason and faith in "revealed" truths - figuratively summarised as Athens and Jerusalem, respectively. Leo Strauss spoke of a "Greater West" which included all areas under the influence of the tension between Greek rationalism and Abrahamic revelation, including the Muslim lands. He was particularly influenced by the great Muslim philosopher Al-Farabi. In order to consider to what extent Eastern philosophy might have partaken of these important tensions, it is perhaps best to consider whether dharma or tao may be equivalent to Nature (by which we mean physis in Greek).

The limits within which reason may be used have been laid down differently in different churches and periods of thought: on the whole, modern religion tends to allow to reason a wide field, reserving, however, as the sphere of faith the ultimate (supernatural) truths of theology.

Reason as an intrinsic part of nature
Wilhelm Reich, the controversial Austrian psychiatrist and naturalist, followed in Hegel's footsteps in perceiving reason not reduced to analytic deduction or mechanistic one-dimensional induction, but as being a primal part of the depth