Reason is the capacity for consciously making sense of things,
establishing and verifying facts, applying logic, and changing or
justifying practices, institutions, and beliefs based on new or
existing information. It is closely associated with such
characteristically human activities as philosophy, science, language,
mathematics, and art and is normally considered to be a distinguishing
ability possessed by humans. Reason, or an aspect of it, is
sometimes referred to as rationality.
Reasoning is associated with thinking, cognition, and intellect. The
philosophical field of logic studies ways in which humans reason
formally through argument. Reasoning may be subdivided into forms
of logical reasoning (forms associated with the strict sense):
deductive reasoning, inductive reasoning, abductive reasoning; and
other modes of reasoning considered more informal, such as intuitive
reasoning and verbal reasoning. Along these lines, a distinction is
often drawn between logical, discursive reasoning (reason proper), and
intuitive reasoning, in which the reasoning process through
intuition—however valid—may tend toward the personal and the
subjectively opaque. In some social and political settings logical and
intuitive modes of reasoning may clash, while in other contexts
intuition and formal reason are seen as complementary rather than
adversarial. For example, in mathematics, intuition is often necessary
for the creative processes involved with arriving at a formal proof,
arguably the most difficult of formal reasoning tasks.
Reasoning, like habit or intuition, is one of the ways by which
thinking moves from one idea to a related idea. For example, reasoning
is the means by which rational individuals understand sensory
information from their environments, or conceptualize abstract
dichotomies such as cause and effect, truth and falsehood, or ideas
regarding notions of good or bad. Reasoning, as a part of executive
decision making, is also closely identified with the ability to
self-consciously change, in terms of goals, beliefs, attitudes,
traditions, and institutions, and therefore with the capacity for
freedom and self-determination. 
In contrast to the use of "reason" as an abstract noun, a reason is a
consideration given which either explains or justifies events,
phenomena, or behavior. Reasons justify decisions, reasons support
explanations of natural phenomena; reasons can be given to explain the
actions (conduct) of individuals.
Using reason, or reasoning, can also be described more plainly as
providing good, or the best, reasons. For example, when evaluating a
moral decision, "morality is, at the very least, the effort to guide
one's conduct by reason--that is, doing what there are the best
reasons for doing--while giving equal [and impartial] weight to the
interests of all those affected by what one does."
Psychologists and cognitive scientists have attempted to study and
explain how people reason, e.g. which cognitive and neural processes
are engaged, and how cultural factors affect the inferences that
people draw. The field of automated reasoning studies how reasoning
may or may not be modeled computationally. Animal psychology considers
the question of whether animals other than humans can reason.
1 Etymology and related words
2 Philosophical history
2.1 Classical philosophy
2.2 Subject-centred reason in early modern philosophy
2.3 Substantive and formal reason
2.4 The critique of reason
Reason compared to related concepts
3.1 Compared to logic
Reason compared to cause-and-effect thinking, and symbolic
3.3 Reason, imagination, mimesis, and memory
Logical reasoning methods and argumentation
3.4.1 Deductive reasoning
3.4.2 Inductive reasoning
3.4.3 Abductive reasoning
3.4.4 Analogical reasoning
3.4.5 Fallacious reasoning
4 Traditional problems raised concerning reason
Reason versus truth, and "first principles"
Reason versus emotion or passion
Reason versus faith or tradition
Reason in particular fields of study
Reason in political philosophy and ethics
5.2.1 Behavioral experiments on human reasoning
5.2.2 Developmental studies of children's reasoning
5.2.3 Neuroscience of reasoning
5.3 Computer science
5.3.1 Automated reasoning
5.4 Evolution of reason
6 See also
8 Further reading
Etymology and related words
English language and other modern European languages, "reason",
and related words, represent words which have always been used to
Latin and classical Greek terms in the sense of their
The original Greek term was "λόγος" logos, the root of the modern
English word "logic" but also a word which could mean for example
"speech" or "explanation" or an "account" (of money handled).
As a philosophical term logos was translated in its non-linguistic
Latin as ratio. This was originally not just a translation
used for philosophy, but was also commonly a translation for logos in
the sense of an account of money.
French raison is derived directly from Latin, and this is the direct
source of the English word "reason".
The earliest major philosophers to publish in English, such as Francis
Bacon, Thomas Hobbes, and
John Locke also routinely wrote in
French, and compared their terms to Greek, treating the words "logos",
"ratio", "raison" and "reason" as inter-changeable. The meaning of the
word "reason" in senses such as "human reason" also overlaps to a
large extent with "rationality" and the adjective of "reason" in
philosophical contexts is normally "rational", rather than "reasoned"
or "reasonable". Some philosophers,
Thomas Hobbes for example,
also used the word ratiocination as a synonym for "reasoning".
Francisco de Goya,
The Sleep of Reason Produces Monsters
The Sleep of Reason Produces Monsters (El sueño de
la razón produce monstruos), c. 1797
The proposal that reason gives humanity a special position in nature
has been argued to be a defining characteristic of western philosophy
and later western modern science, starting with classical Greece.
Philosophy can be described as a way of life based upon reason, and in
the other direction reason has been one of the major subjects of
philosophical discussion since ancient times.
Reason is often said to
be reflexive, or "self-correcting," and the critique of reason has
been a persistent theme in philosophy. It has been defined in
different ways, at different times, by different thinkers about human
For many classical philosophers, nature was understood teleologically,
meaning that every type of thing had a definitive purpose which fit
within a natural order that was itself understood to have aims.
Perhaps starting with
Pythagoras or Heraclitus, the cosmos is even
said to have reason. Reason, by this account, is not just one
characteristic that humans happen to have, and that influences
happiness amongst other characteristics.
Reason was considered of
higher stature than other characteristics of human nature, such as
sociability, because it is something humans share with nature itself,
linking an apparently immortal part of the human mind with the divine
order of the cosmos itself. Within the human mind or soul (psyche),
reason was described by
Plato as being the natural monarch which
should rule over the other parts, such as spiritedness (thumos) and
the passions. Aristotle, Plato's student, defined human beings as
rational animals, emphasizing reason as a characteristic of human
nature. He defined the highest human happiness or well being
(eudaimonia) as a life which is lived consistently, excellently and
completely in accordance with reason.
The conclusions to be drawn from the discussions of
Plato on this matter are amongst the most debated in the history of
philosophy. But teleological accounts such as Aristotle's were
highly influential for those who attempt to explain reason in a way
which is consistent with monotheism and the immortality and divinity
of the human soul. For example, in the neo-platonist account of
Plotinus, the cosmos has one soul, which is the seat of all reason,
and the souls of all individual humans are part of this soul. Reason
Plotinus both the provider of form to material things, and the
light which brings individuals souls back into line with their
source. Such neo-Platonist accounts of the rational part of the
human soul were standard amongst medieval Islamic philosophers, and
under this influence, mainly via Averroes, came to be debated
Europe until well into the renaissance, and they remain
important in Iranian philosophy.
Subject-centred reason in early modern philosophy
The early modern era was marked by a number of significant changes in
the understanding of reason, starting in Europe. One of the most
important of these changes involved a change in the metaphysical
understanding of human beings. Scientists and philosophers began to
question the teleological understanding of the world.
no longer assumed to be human-like, with its own aims or reason, and
human nature was no longer assumed to work according to anything other
than the same "laws of nature" which affect inanimate things. This new
understanding eventually displaced the previous world view that
derived from a spiritual understanding of the universe.
Accordingly, in the 17th century,
René Descartes explicitly rejected
the traditional notion of humans as "rational animals," suggesting
instead that they are nothing more than "thinking things" along the
lines of other "things" in nature. Any grounds of knowledge outside
that understanding was, therefore, subject to doubt.
In his search for a foundation of all possible knowledge, Descartes
deliberately decided to throw into doubt all knowledge – except that
of the mind itself in the process of thinking:
At this time I admit nothing that is not necessarily true. I am
therefore precisely nothing but a thinking thing; that is a mind, or
intellect, or understanding, or reason – words of whose meanings I
was previously ignorant.
This eventually became known as epistemological or "subject-centred"
reason, because it is based on the knowing subject, who perceives the
rest of the world and itself as a set of objects to be studied, and
successfully mastered by applying the knowledge accumulated through
such study. Breaking with tradition and many thinkers after him,
Descartes explicitly did not divide the incorporeal soul into parts,
such as reason and intellect, describing them as one indivisible
A contemporary of Descartes,
Thomas Hobbes described reason as a
broader version of "addition and subtraction" which is not limited to
numbers. This understanding of reason is sometimes termed
"calculative" reason. Similar to Descartes, Hobbes asserted that "No
discourse whatsoever, can end in absolute knowledge of fact, past, or
to come" but that "sense and memory" is absolute knowledge.
In the late 17th century, through the 18th century,
John Locke and
David Hume developed Descartes' line of thought still further. Hume
took it in an especially skeptical direction, proposing that there
could be no possibility of deducing relationships of cause and effect,
and therefore no knowledge is based on reasoning alone, even if it
Hume famously remarked that, "We speak not strictly and
philosophically when we talk of the combat of passion and of reason.
Reason is, and ought only to be the slave of the passions, and can
never pretend to any other office than to serve and obey them."
Hume also took his definition of reason to unorthodox extremes by
arguing, unlike his predecessors, that human reason is not
qualitatively different from either simply conceiving individual
ideas, or from judgments associating two ideas, and that "reason
is nothing but a wonderful and unintelligible instinct in our souls,
which carries us along a certain train of ideas, and endows them with
particular qualities, according to their particular situations and
relations." It followed from this that animals have reason, only
much less complex than human reason.
In the 18th century,
Immanuel Kant attempted to show that Hume was
wrong by demonstrating that a "transcendental" self, or "I", was a
necessary condition of all experience. Therefore, suggested Kant, on
the basis of such a self, it is in fact possible to reason both about
the conditions and limits of human knowledge. And so long as these
limits are respected, reason can be the vehicle of morality, justice,
aesthetics, theories of knowledge (epistemology), and understanding.
Substantive and formal reason
In the formulation of Kant, who wrote some of the most influential
modern treatises on the subject, the great achievement of reason
(German: Vernunft) is that it is able to exercise a kind of universal
law-making. Kant was able therefore to re-formulate the basis of
moral-practical, theoretical and aesthetic reasoning, on "universal"
Here practical reasoning is the self-legislating or self-governing
formulation of universal norms, and theoretical reasoning the way
humans posit universal laws of nature.
Under practical reason, the moral autonomy or freedom of human beings
depends on their ability to behave according to laws that are given to
them by the proper exercise of that reason. This contrasted with
earlier forms of morality, which depended on religious understanding
and interpretation, or nature for their substance.
According to Kant, in a free society each individual must be able to
pursue their goals however they see fit, so long as their actions
conform to principles given by reason. He formulated such a principle,
called the "categorical imperative", which would justify an action
only if it could be universalized:
Act only according to that maxim whereby you can, at the same time,
will that it should become a universal law.
In contrast to Hume then, Kant insists that reason itself (German
Vernunft) has natural ends itself, the solution to the metaphysical
problems, especially the discovery of the foundations of morality.
Kant claimed that this problem could be solved with his
"transcendental logic" which unlike normal logic is not just an
instrument, which can be used indifferently, as it was for Aristotle,
but a theoretical science in its own right and the basis of all the
According to Jürgen Habermas, the "substantive unity" of reason has
dissolved in modern times, such that it can no longer answer the
question "How should I live?" Instead, the unity of reason has to be
strictly formal, or "procedural." He thus described reason as a group
of three autonomous spheres (on the model of Kant's three critiques):
Cognitive-instrumental reason is the kind of reason employed by the
sciences. It is used to observe events, to predict and control
outcomes, and to intervene in the world on the basis of its
Moral-practical reason is what we use to deliberate and discuss issues
in the moral and political realm, according to universalizable
procedures (similar to Kant's categorical imperative); and
Aesthetic reason is typically found in works of art and literature,
and encompasses the novel ways of seeing the world and interpreting
things that those practices embody.
For Habermas, these three spheres are the domain of experts, and
therefore need to be mediated with the "lifeworld" by philosophers. In
drawing such a picture of reason, Habermas hoped to demonstrate that
the substantive unity of reason, which in pre-modern societies had
been able to answer questions about the good life, could be made up
for by the unity of reason's formalizable procedures.
The critique of reason
Hamann, Herder, Kant, Hegel, Kierkegaard, Nietzsche, Heidegger,
Foucault, Rorty, and many other philosophers have contributed to a
debate about what reason means, or ought to mean. Some, like
Kierkegaard, Nietzsche, and Rorty, are skeptical about
subject-centred, universal, or instrumental reason, and even skeptical
toward reason as a whole. Others, including Hegel, believe that it has
obscured the importance of intersubjectivity, or "spirit" in human
life, and attempt to reconstruct a model of what reason should be.
Some thinkers, e.g. Foucault, believe there are other forms of reason,
neglected but essential to modern life, and to our understanding of
what it means to live a life according to reason.
In the last several decades, a number of proposals have been made to
"re-orient" this critique of reason, or to recognize the "other
voices" or "new departments" of reason:
For example, in opposition to subject-centred reason, Habermas has
proposed a model of communicative reason that sees it as an
essentially cooperative activity, based on the fact of linguistic
Nikolas Kompridis has proposed a widely encompassing view of reason as
"that ensemble of practices that contributes to the opening and
preserving of openness" in human affairs, and a focus on reason's
possibilities for social change.
The philosopher Charles Taylor, influenced by the 20th century German
philosopher Martin Heidegger, has proposed that reason ought to
include the faculty of disclosure, which is tied to the way we make
sense of things in everyday life, as a new "department" of reason.
In the essay "What is Enlightenment?",
Michel Foucault proposed a
concept of critique based on Kant's distinction between "private" and
"public" uses of reason. This distinction, as suggested, has two
Private reason is the reason that is used when an individual is "a cog
in a machine" or when one "has a role to play in society and jobs to
do: to be a soldier, to have taxes to pay, to be in charge of a
parish, to be a civil servant."
Public reason is the reason used "when one is reasoning as a
reasonable being (and not as a cog in a machine), when one is
reasoning as a member of reasonable humanity." In these circumstances,
"the use of reason must be free and public."
Reason compared to related concepts
Compared to logic
Main article: Logic
The terms "logic" or "logical" are sometimes used as if they were
identical with the term "reason" or with the concept of being
"rational", or sometimes logic is seen as the most pure or the
defining form of reason. For example in modern economics, rational
choice is assumed to equate to logically consistent choice.
Reason and logic can however be thought of as distinct, although logic
is one important aspect of reason. Author Douglas Hofstadter, in
Gödel, Escher, Bach, characterizes the distinction in this way. Logic
is done inside a system while reason is done outside the system by
such methods as skipping steps, working backward, drawing diagrams,
looking at examples, or seeing what happens if you change the rules of
Reason is a type of thought, and the word "logic" involves the attempt
to describe rules or norms by which reasoning operates, so that
orderly reasoning can be taught. The oldest surviving writing to
explicitly consider the rules by which reason operates are the works
of the Greek philosopher Aristotle, especially Prior Analysis and
Posterior Analysis. Although the Ancient Greeks had no separate
word for logic as distinct from language and reason, Aristotle's newly
coined word "syllogism" (syllogismos) identified logic clearly for the
first time as a distinct field of study. When
Aristotle referred to
"the logical" (hē logikē), he was referring more broadly to rational
Reason compared to cause-and-effect thinking, and symbolic
Causality and Symbols
As pointed out by philosophers such as Hobbes, Locke and Hume, some
animals are also clearly capable of a type of "associative thinking",
even to the extent of associating causes and effects. A dog once
kicked, can learn how to recognize the warning signs and avoid being
kicked in the future, but this does not mean the dog has reason in any
strict sense of the word. It also does not mean that humans acting on
the basis of experience or habit are using their reason.
Human reason requires more than being able to associate two ideas,
even if those two ideas might be described by a reasoning human as a
cause and an effect, perceptions of smoke, for example, and memories
of fire. For reason to be involved, the association of smoke and the
fire would have to be thought through in a way which can be explained,
for example as cause and effect. In the explanation of Locke, for
example, reason requires the mental use of a third idea in order to
make this comparison by use of syllogism.
More generally, reason in the strict sense requires the ability to
create and manipulate a system of symbols, as well as indices and
icons, according to Charles Sanders Peirce, the symbols having only a
nominal, though habitual, connection to either smoke or fire. One
example of such a system of artificial symbols and signs is language.
The connection of reason to symbolic thinking has been expressed in
different ways by philosophers.
Thomas Hobbes described the creation
of "Markes, or Notes of remembrance" (Leviathan Ch.4) as speech. He
used the word speech as an English version of the Greek word logos so
that speech did not need to be communicated. When communicated,
such speech becomes language, and the marks or notes or remembrance
are called "Signes" by Hobbes. Going further back, although Aristotle
is a source of the idea that only humans have reason (logos), he does
mention that animals with imagination, for whom sense perceptions can
persist, come closest to having something like reasoning and nous, and
even uses the word "logos" in one place to describe the distinctions
which animals can perceive in such cases.
Reason, imagination, mimesis, and memory
Main articles: Imagination, Mimesis, Memory, and Recollection
Reason and imagination rely on similar mental processes.
Imagination is not only found in humans. Aristotle, for example,
stated that phantasia (imagination: that which can hold images or
phantasmata) and phronein (a type of thinking that can judge and
understand in some sense) also exist in some animals. According to
him, both are related to the primary perceptive ability of animals,
which gathers the perceptions of different senses and defines the
order of the things that are perceived without distinguishing
universals, and without deliberation or logos. But this is not yet
reason, because human imagination is different.
The recent modern writings of
Terrence Deacon and Merlin Donald,
writing about the origin of language, also connect reason connected to
not only language, but also mimesis, More specifically they
describe the ability to create language as part of an internal
modeling of reality specific to humankind. Other results are
consciousness, and imagination or fantasy. In contrast, modern
proponents of a genetic pre-disposition to language itself include
Noam Chomsky and Steven Pinker, to whom Donald and Deacon can be
As reason is symbolic thinking, and peculiarly human, then this
implies that humans have a special ability to maintain a clear
consciousness of the distinctness of "icons" or images and the real
things they represent. Starting with a modern author, Merlin Donald
A dog might perceive the "meaning" of a fight that was realistically
play-acted by humans, but it could not reconstruct the message or
distinguish the representation from its referent (a real fight). [...]
Trained apes are able to make this distinction; young children make
this distinction early – hence, their effortless distinction between
play-acting an event and the event itself
In classical descriptions, an equivalent description of this mental
faculty is eikasia, in the philosophy of Plato. This is the
ability to perceive whether a perception is an image of something
else, related somehow but not the same, and therefore allows humans to
perceive that a dream or memory or a reflection in a mirror is not
reality as such. What Klein refers to as dianoetic eikasia is the
eikasia concerned specifically with thinking and mental images, such
as those mental symbols, icons, signes, and marks discussed above as
definitive of reason. Explaining reason from this direction: human
thinking is special in the way that we often understand visible things
as if they were themselves images of our intelligible "objects of
thought" as "foundations" (hypothēses in Ancient Greek). This
thinking (dianoia) is "...an activity which consists in making the
vast and diffuse jungle of the visible world depend on a plurality of
more 'precise' noēta."
Merlin Donald and the Socratic authors such
Plato and Aristotle
emphasize the importance of mimesis, often translated as imitation or
representation. Donald writes
Imitation is found especially in monkeys and apes [... but ...]
Mimesis is fundamentally different from imitation and mimicry in that
it involves the invention of intentional representations. [...]
Mimesis is not absolutely tied to external communication.
Mimēsis is a concept, now popular again in academic discussion, that
was particularly prevalent in Plato's works, and within Aristotle, it
is discussed mainly in the Poetics. In Michael Davis's account of the
theory of man in this work.
It is the distinctive feature of human action, that whenever we choose
what we do, we imagine an action for ourselves as though we were
inspecting it from the outside. Intentions are nothing more than
imagined actions, internalizings of the external. All action is
therefore imitation of action; it is poetic...
Plato (and Aristotle, especially in On
Recollection), emphasizes the peculiarity in humans of voluntary
initiation of a search through one's mental world. The ancient Greek
anamnēsis, normally translated as "recollection" was opposed to mneme
or memory. Memory, shared with some animals, requires a
consciousness not only of what happened in the past, but also that
something happened in the past, which is in other words a kind of
eikasia "...but nothing except man is able to recollect."
Recollection is a deliberate effort to search for and recapture
something once known. Klein writes that, "To become aware of our
having forgotten something means to begin recollecting." Donald
calls the same thing autocueing, which he explains as follows:
"Mimetic acts are reproducible on the basis of internal,
self-generated cues. This permits voluntary recall of mimetic
representations, without the aid of external cues – probably the
earliest form of representational thinking."
In a celebrated paper in modern times, the fantasy author and
J.R.R. Tolkien wrote in his essay "On Fairy Stories" that
the terms "fantasy" and "enchantment" are connected to not only
"....the satisfaction of certain primordial human desires...." but
also "...the origin of language and of the mind."
Logical reasoning methods and argumentation
Looking at logical categorizations of different types of reasoning the
traditional main division made in philosophy is between deductive
reasoning and inductive reasoning. Formal logic has been described as
the science of deduction. The study of inductive reasoning is
generally carried out within the field known as informal logic or
Main article: Deductive reasoning
A subdivision of
Philosophy is Logic.
Logic is the study of reasoning.
Deduction is a form of reasoning in which a conclusion follows
necessarily from the stated premises. A deduction is also the
conclusion reached by a deductive reasoning process. One classic
example of deductive reasoning is that found in syllogisms like the
Premise 1: All humans are mortal.
Premise 2: Socrates is a human.
Conclusion: Socrates is mortal.
The reasoning in this argument is valid, because there is no way in
which the premises, 1 and 2, could be true and the conclusion, 3, be
Main article: Inductive reasoning
Induction is a form of inference producing propositions about
unobserved objects or types, either specifically or generally, based
on previous observation. It is used to ascribe properties or relations
to objects or types based on previous observations or experiences, or
to formulate general statements or laws based on limited observations
of recurring phenomenal patterns.
Inductive reasoning contrasts strongly with deductive reasoning in
that, even in the best, or strongest, cases of inductive reasoning,
the truth of the premises does not guarantee the truth of the
conclusion. Instead, the conclusion of an inductive argument follows
with some degree of probability. Relatedly, the conclusion of an
inductive argument contains more information than is already contained
in the premises. Thus, this method of reasoning is ampliative.
A classic example of inductive reasoning comes from the empiricist
Premise: The sun has risen in the east every morning up until now.
Conclusion: The sun will also rise in the east tomorrow.
Main article: Abductive reasoning
Abductive reasoning, or argument to the best explanation, is a form of
inductive reasoning, since the conclusion in an abductive argument
does not follow with certainty from its premises and concerns
something unobserved. What distinguishes abduction from the other
forms of reasoning is an attempt to favour one conclusion above
others, by attempting to falsify alternative explanations or by
demonstrating the likelihood of the favoured conclusion, given a set
of more or less disputable assumptions. For example, when a patient
displays certain symptoms, there might be various possible causes, but
one of these is preferred above others as being more probable.
Main article: Analogical reasoning
Analogical reasoning is reasoning from the particular to the
particular. It is often used in case-based reasoning, especially legal
reasoning. An example follows:
Premise 1: Socrates is human and mortal.
Plato is human.
Plato is mortal.
Analogical reasoning can be viewed as a form of inductive reasoning
from a single example, but if it is intended as inductive reasoning it
is a bad example, because inductive reasoning typically uses a large
number of examples to reason from the particular to the general.
Analogical reasoning often leads to wrong conclusions. For example:
Premise 1: Socrates is human and male.
Ada Lovelace is human.
Ada Lovelace is male.
Main articles: Fallacy, Formal fallacy, and Informal fallacy
Flawed reasoning in arguments is known as fallacious reasoning. Bad
reasoning within arguments can be because it commits either a formal
fallacy or an informal fallacy.
Formal fallacies occur when there is a problem with the form, or
structure, of the argument. The word "formal" refers to this link to
the form of the argument. An argument that contains a formal fallacy
will always be invalid.
An informal fallacy is an error in reasoning that occurs due to a
problem with the content, rather than mere structure, of the argument.
Traditional problems raised concerning reason
Philosophy is sometimes described as a life of reason, with normal
human reason pursued in a more consistent and dedicated way than
usual. Two categories of problem concerning reason have long been
discussed by philosophers concerning reason, essentially being
reasonings about reasoning itself as a human aim, or philosophizing
about philosophizing. The first question is concerning whether we can
be confident that reason can achieve knowledge of truth better than
other ways of trying to achieve such knowledge. The other question is
whether a life of reason, a life that aims to be guided by reason, can
be expected to achieve a happy life more so than other ways of life
(whether such a life of reason results in knowledge or not).
Reason versus truth, and "first principles"
See also: Truth, First principle, and Nous
Since classical times a question has remained constant in
philosophical debate (which is sometimes seen as a conflict between
Platonism and Aristotelianism) concerning the role of
reason in confirming truth. People use logic, deduction, and
induction, to reach conclusions they think are true. Conclusions
reached in this way are considered more certain than sense perceptions
on their own. On the other hand, if such reasoned conclusions are
only built originally upon a foundation of sense perceptions, then,
our most logical conclusions can never be said to be certain because
they are built upon the very same fallible perceptions they seek to
This leads to the question of what types of first principles, or
starting points of reasoning, are available for someone seeking to
come to true conclusions. In Greek, "first principles" are archai,
"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 or consciousness.
Empiricism (sometimes associated with Aristotle but more correctly
associated with British philosophers such as
John Locke and David
Hume, as well as their ancient equivalents such as Democritus) asserts
that sensory impressions are the only available starting points for
reasoning and attempting to attain truth. This approach always leads
to the controversial conclusion that absolute knowledge is not
attainable. Idealism, (associated with
Plato and his school), claims
that there is a "higher" reality, from which certain people can
directly arrive at truth without needing to rely only upon the senses,
and that this higher reality is therefore the primary source of truth.
Philosophers such as Plato, Aristotle, Al-Farabi, Avicenna, Averroes,
Hegel are sometimes said to have argued that
reason must be fixed and discoverable—perhaps by dialectic,
analysis, or study. In the vision of these thinkers, reason is divine
or at least has divine attributes. Such an approach allowed religious
philosophers such as Thomas
Étienne Gilson to try to show
that reason and revelation are compatible. According to Hegel, "...the
only thought which
Philosophy brings with it to the contemplation of
History, is the simple conception of reason; that reason is the
Sovereign of the World; that the history of the world, therefore,
presents us with a rational process."
Since the 17th century rationalists, reason has often been taken to be
a subjective faculty, or rather the unaided ability (pure reason) to
form concepts. For Descartes,
Spinoza and Leibniz, this was associated
with mathematics. Kant attempted to show that pure reason could 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.
Reason versus emotion or passion
Emotion and Passion (emotion)
Plato and Aristotle, western literature often treated reason as
being the faculty that trained the passions and appetites.[citation
Stoic philosophy by contrast considered all passions
bad. After the critiques of reason in the early
Enlightenment the appetites were rarely discussed or conflated with
the passions. Some Enlightenment camps took after the
Stoics to say
Reason should oppose Passion rather than order it, while
others like the Romantics believed that Passion displaces Reason, as
in the maxim "follow your heart".
Reason has been seen as a slave, or judge, of the passions, notably in
the work of David Hume, and more recently of Freud.
Reasoning which claims that the object of a desire is demanded by
logic alone is called rationalization.
Rousseau first proposed, in his second Discourse, that reason and
political life is not natural and possibly harmful to mankind. He
asked what really can be said about what is natural to mankind. What,
other than reason and civil society, "best suits his constitution"?
Rousseau saw "two principles prior to reason" in human nature. First
we hold an intense interest in our own well-being. Secondly we object
to the suffering or death of any sentient being, especially one like
ourselves. These two passions lead us to desire more than we could
achieve. We become dependent upon each other, and on relationships of
authority and obedience. This effectively puts the human race into
Rousseau says that he almost dares to assert that nature does
not destine men to be healthy. According to Velkley, "Rousseau
outlines certain programs of rational self-correction, most notably
the political legislation of the Contrat Social and the moral
education in Émile. All the same,
Rousseau understands such
corrections to be only ameliorations of an essentially unsatisfactory
condition, that of socially and intellectually corrupted humanity."
This quandary presented by
Rousseau led to Kant's new way of
justifying reason as freedom to create good and evil. These therefore
are not to be blamed on nature or God. In various ways, German
Idealism after Kant, and major later figures such Nietzsche, Bergson,
Husserl, Scheler, and Heidegger, remain pre-occupied with problems
coming from the metaphysical demands or urges of reason. The
Rousseau and these later writers is also large upon art
and politics. Many writers (such as Nikos Kazantzakis) extol passion
and disparage reason. In politics modern nationalism comes from
Rousseau's argument that rationalist cosmopolitanism brings man ever
further from his natural state.
Another view on reason and emotion was proposed in the 1994 book
Descartes' Error by Antonio Damasio. In it, Damasio presents
the "Somatic Marker Hypothesis" which states that emotions guide
behavior and decision-making. Damasio argues that these somatic
markers (known collectively as "gut feelings") are "intuitive signals"
that direct our decision making processes in a certain way that cannot
be solved with rationality alone. Damasio further argues that
rationality requires emotional input in order to function.
Reason versus faith or tradition
Main articles: Faith, Religion, and Tradition
There are many religious traditions, some of which are explicitly
fideist and others of which claim varying degrees of rationalism.
Secular critics sometimes accuse all religious adherents of
irrationality, since they claim such adherents are guilty of ignoring,
suppressing, or forbidding some kinds of reasoning concerning some
subjects (such as religious dogmas, moral taboos, etc.). Though
the theologies and religions such as classical monotheism typically do
not claim to be irrational, there is often a perceived conflict or
tension between faith and tradition on the one hand, and reason on the
other, as potentially competing sources of wisdom, law and
Religious adherents sometimes respond by arguing that faith and reason
can be reconciled, or have different non-overlapping domains, or that
critics engage in a similar kind of irrationalism:
Alvin Plantinga argues that there is no
real conflict between reason and classical theism because classical
theism explains (among other things) why the universe is intelligible
and why reason can successfully grasp it.
Non-overlapping magisteria: Evolutionary biologist Stephen Jay Gould
argues that there need not be conflict between reason and religious
belief because they are each authoritative in their own domain (or
"magisterium"). For example, perhaps reason alone is not
enough to explain such big questions as the origins of the universe,
the origin of life, the origin of consciousness, the foundation of
morality, or the destiny of the human race. If so, reason can work on
those problems over which it has authority while other sources of
knowledge or opinion can have authority on the big questions.
Alasdair MacIntyre and Charles Taylor argue
that those critics of traditional religion who are adherents of
secular liberalism are also sometimes guilty of ignoring, suppressing,
and forbidding some kinds of reasoning about subjects.
Similarly, philosophers of science such as Paul Feyaraband argue that
scientists sometimes ignore or suppress evidence contrary to the
Unification: Theologian Joseph Ratzinger, later Benedict XVI, asserted
that "Christianity has understood itself as the religion of the Logos,
as the religion according to reason," referring to John 1:Ἐν
ἀρχῇ ἦν ὁ λόγος, usually translated as "In the
beginning was the Word (Logos)." Thus, he said that the Christian
faith is "open to all that is truly rational," and that the
rationality of Western Enlightenment "is of Christian origin".
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
Athens and Jerusalem, respectively. Leo Strauss
spoke of a "Greater West" that included all areas under the influence
of the tension between Greek rationalism and
Muslim lands. He was particularly influenced by the
Muslim philosopher Al-Farabi. To consider to what extent Eastern
philosophy might have partaken of these important tensions, Strauss
thought it best to consider whether dharma or tao may be equivalent to
Nature (by which we mean physis in Greek). According to Strauss the
beginning of philosophy involved the "discovery or invention of
nature" and the "pre-philosophical equivalent of nature" was supplied
by "such notions as 'custom' or 'ways'", which appear to be really
universal in all times and places. The philosophical concept of nature
or natures as a way of understanding archai (first principles of
knowledge) brought about a peculiar tension between reasoning on the
one hand, and tradition or faith on the other.
Although there is this special history of debate concerning reason and
faith in the Islamic, Christian and Jewish traditions, the pursuit of
reason is sometimes argued to be compatible with the other practice of
other religions of a different nature, such as Hinduism, because they
do not define their tenets in such an absolute way.
Reason in particular fields of study
Reason in political philosophy and ethics
Main articles: Political Philosophy, Ethics, and The Good
Aristotle famously described reason (with language) as a part of human
nature, which means that it is best for humans to live "politically"
meaning in communities of about the size and type of a small city
state (polis in Greek). For example...
It is clear, then, that a human being is more of a political
[politikon = of the polis] animal [zōion] than is any bee or than any
of those animals that live in herds. For nature, as we say, makes
nothing in vain, and humans are the only animals who possess reasoned
speech [logos]. Voice, of course, serves to indicate what is painful
and pleasant; that is why it is also found in other animals, because
their nature has reached the point where they can perceive what is
painful and pleasant and express these to each other. But speech
[logos] serves to make plain what is advantageous and harmful and so
also what is just and unjust. For it is a peculiarity of humans, in
contrast to the other animals, to have perception of good and bad,
just and unjust, and the like; and the community in these things makes
a household or city [polis]. [...] By nature, then, the drive for such
a community exists in everyone, but the first to set one up is
responsible for things of very great goodness. For as humans are the
best of all animals when perfected, so they are the worst when
divorced from law and right. The reason is that injustice is most
difficult to deal with when furnished with weapons, and the weapons a
human being has are meant by nature to go along with prudence and
virtue, but it is only too possible to turn them to contrary uses.
Consequently, if a human being lacks virtue, he is the most unholy and
savage thing, and when it comes to sex and food, the worst. But
justice is something political [to do with the polis], for right is
the arrangement of the political community, and right is
discrimination of what is just. (
Aristotle's Politics 1253a 1.2. Peter
Simpson's translation, with Greek terms inserted in square brackets.)
The concept of human nature being fixed in this way, implied, in other
words, that we can define what type of community is always best for
people. This argument has remained a central argument in all
political, ethical and moral thinking since then, and has become
especially controversial since firstly Rousseau's Second Discourse,
and secondly, the
Theory of Evolution. Already in
Aristotle there was
an awareness that the polis had not always existed and had needed to
be invented or developed by humans themselves. The household came
first, and the first villages and cities were just extensions of that,
with the first cities being run as if they were still families with
Kings acting like fathers.
Friendship [philia] seems to prevail [in] man and woman according to
nature [kata phusin]; for people are by nature [tēi phusei] pairing
[sunduastikon] more than political [politikon = of the polis],
inasmuch as the household [oikos] is prior [proteron = earlier] and
more necessary than the polis and making children is more common
[koinoteron] with the animals. In the other animals, community
[koinōnia] goes no further than this, but people live together
[sumoikousin] not only for the sake of making children, but also for
the things for life; for from the start the functions [erga] are
divided, and are different [for] man and woman. Thus they supply each
other, putting their own into the common [eis to koinon]. It is for
these [reasons] that both utility [chrēsimon] and pleasure [hēdu]
seem to be found in this kind of friendship. (Nicomachean Ethics,
VIII.12.1162a. Rough literal translation with Greek terms shown in
Rousseau in his Second Discourse finally took the shocking step of
claiming that this traditional account has things in reverse: with
reason, language and rationally organized communities all having
developed over a long period of time merely as a result of the fact
that some habits of cooperation were found to solve certain types of
problems, and that once such cooperation became more important, it
forced people to develop increasingly complex cooperation—often only
to defend themselves from each other.
In other words, according to Rousseau, reason, language and rational
community did not arise because of any conscious decision or plan by
humans or gods, nor because of any pre-existing human nature. As a
result, he claimed, living together in rationally organized
communities like modern humans is a development with many negative
aspects compared to the original state of man as an ape. If anything
is specifically human in this theory, it is the flexibility and
adaptability of humans. This view of the animal origins of distinctive
human characteristics later received support from Charles Darwin's
Theory of Evolution.
The two competing theories concerning the origins of reason are
relevant to political and ethical thought because, according to the
Aristotelian theory, a best way of living together exists
independently of historical circumstances. According to Rousseau, we
should even doubt that reason, language and politics are a good thing,
as opposed to being simply the best option given the particular course
of events that lead to today. Rousseau's theory, that human nature is
malleable rather than fixed, is often taken to imply, for example by
Karl Marx, a wider range of possible ways of living together than
However, while Rousseau's initial impact encouraged bloody revolutions
against traditional politics, including both the
French Revolution and
the Russian Revolution, his own conclusions about the best forms of
community seem to have been remarkably classical, in favor of
city-states such as Geneva, and rural living.
Psychology of reasoning
Scientific research into reasoning is carried out within the fields of
psychology and cognitive science. Psychologists attempt to determine
whether or not people are capable of rational thought in a number of
Assessing how well someone engages in reasoning is the project of
determining the extent to which the person is rational or acts
rationally. It is a key research question in the psychology of
Rationality is often divided into its respective
theoretical and practical counterparts.
Behavioral experiments on human reasoning
Experimental cognitive psychologists carry out research on reasoning
behaviour. Such research may focus, for example, on how people perform
on tests of reasoning such as intelligence or IQ tests, or on how well
people's reasoning matches ideals set by logic (see, for example, the
Wason test). Experiments examine how people make inferences from
conditionals e.g., If A then B and how they make inferences about
alternatives, e.g., A or else B. They test whether people can make
valid deductions about spatial and temporal relations, e.g., A is to
the left of B, or A happens after B, and about quantified assertions,
e.g., All the A are B. Experiments investigate how people make
inferences about factual situations, hypothetical possibilities,
probabilities, and counterfactual situations.
Developmental studies of children's reasoning
Developmental psychologists investigate the development of reasoning
from birth to adulthood. Piaget's theory of cognitive development was
the first complete theory of reasoning development. Subsequently,
several alternative theories were proposed, including the
neo-Piagetian theories of cognitive development.
Neuroscience of reasoning
The biological functioning of the brain is studied by
neurophysiologists and neuropsychologists. Research in this area
includes research into the structure and function of normally
functioning brains, and of damaged or otherwise unusual brains. In
addition to carrying out research into reasoning, some psychologists,
for example, clinical psychologists and psychotherapists work to alter
people's reasoning habits when they are unhelpful.
Automated reasoning and Computational logic
In artificial intelligence and computer science, scientists study and
use automated reasoning for diverse applications including automated
theorem proving the formal semantics of programming languages, and
formal specification in software engineering.
Main article: Metacognition
Meta-reasoning is reasoning about reasoning. In computer science, a
system performs meta-reasoning when it is reasoning about its own
operation. This requires a programming language capable of
reflection, the ability to observe and modify its own structure and
Evolution of reason
This section needs expansion. You can help by adding to it. (August
Dan Sperber believes that reasoning in groups is more effective and
promotes their evolutionary fitness.
A species could benefit greatly from better abilities to reason about,
predict and understand the world. French social and cognitive
Dan Sperber and Hugo Mercier argue that there could have
been other forces driving the evolution of reason. They point out that
reasoning is very difficult for humans to do effectively, and that it
is hard for individuals to doubt their own beliefs (confirmation
bias). Reasoning is most effective when it is done as a collective -
as demonstrated by the success of projects like science. They suggest
that there are not just individual, but group selection pressures at
play. Any group that managed to find ways of reasoning effectively
would reap benefits for all its members, increasing their fitness.
This could also help explain why humans, according to Sperber, are not
optimized to reason effectively alone. Their argumentative theory of
reasoning claims that reason may have more to do with winning
arguments than with the search for the truth.
Logic and rationality
Outline of thought - topic tree that identifies many types of
thoughts/thinking, types of reasoning, aspects of thought, related
fields, and more.
Outline of human intelligence - topic tree presenting the traits,
capacities, models, and research fields of human intelligence, and
^ Kompridis, Nikolas (2000). "So We Need Something Else for
Mean". International Journal of Philosophical Studies. 8: 271–295.
^ individuals, for example, "humans have reason." Compare: MacIntyre,
Alasdair (2013). Dependent Rational Animals: Why
Human Beings Need the
Virtues. The Paul Carus Lectures. Open Court. ISBN 9780812697056.
Retrieved 2014-12-01. [...] the exercise of independent practical
reasoning is one essential constituent to full human
^ Hintikka, J. "
Philosophy of logic". Encyclopædia Britannica.
Encyclopædia Britannica, Inc. Retrieved 12 November 2013.
^ Aristotle, Nicomachean
Ethics 6 – The Intellectual Virtues
^ Michel Foucault, "What is Enlightenment?" in The Essential Foucault,
eds. Paul Rabinow and Nikolas Rose, New York: The New Press, 2003,
43-57. See also Nikolas Kompridis, "The Idea of a New Beginning: A
Romantic Source of Normativity and Freedom," in Philosophical
Romanticism, New York: Routledge, 2006, 32-59; "So We Need Something
Reason to Mean", International Journal of Philosophical
Studies 8: 3, 271 — 295.
^ a b Merriam-Webster.com Merriam-Webster Dictionary definition of
^ Rachels, James. The Elements of Moral Philosophy, 4th ed. McGraw
^ Liddell, Henry George; Scott, Robert, "logos", A Greek-English
Lexicon . For etymology of English "logic" see any dictionary
such as the Merriam Webster entry for logic.
^ Lewis, Charlton; Short, Charles, "ratio", A
^ See Merriam Webster "rational" and Merriam Webster "reasonable".
^ a b Habermas, Jürgen (1990). The Philosophical Discourse of
Modernity. Cambridge, MA: MIT Press.
^ Kirk; Raven; Schofield (1983), The Presocratic
ed.), Cambridge University Press . See pages 204 and 235.
Ethics Book 1.
^ a b Davidson, Herbert (1992), Alfarabi, Avicenna, and Averroes, on
Intellect, Oxford University Press , page 3.
^ Moore, Edward, "Plotinus", Internet Encyclopedia of Philosophy
^ Dreyfus, Hubert. "Telepistemology: Descartes' Last Stand".
socrates.berkeley.edu. Retrieved February 23, 2011.
^ Descartes, "Second Meditation".
^ Hobbes, Thomas, Molesworth, ed., De Corpore : "We must not
therefore think that computation, that is, ratiocination, has place
only in numbers, as if man were distinguished from other living
creatures (which is said to have been the opinion of Pythagoras) by
nothing but the faculty of numbering; for magnitude, body, motion,
time, degrees of quality, action, conception, proportion, speech and
names (in which all the kinds of philosophy consist) are capable of
addition and substraction [sic]. Now such things as we add or
substract, that is, which we put into an account, we are said to
consider, in Greek λογίζεσθαι [logizesthai], in which
language also συλλογίζεσθι [syllogizesthai] signifies to
compute, reason, or reckon."
^ Hobbes, Thomas, "VII. Of the ends, or resolutions of discourse", The
English Works of Thomas Hobbes, 3 (Leviathan) and Hobbes,
Thomas, "IX. Of the several subjects of knowledge", The English Works
of Thomas Hobbes, 3 (Leviathan)
^ Locke, John (1824) , "XXVII On Identity and Diversity", An
Understanding Part 1, The Works of John Locke
in Nine Volumes (12th ed.), Rivington
^ Hume, David, "I.IV.VI. Of Personal Identity", A Treatise of Human
^ Hume, David, "II.III.III. Of the influencing motives of the will.",
A Treatise of
^ Hume, David, "I.III.VII (footnote) Of the
Nature of the Idea Or
Belief", A Treatise of
^ Hume, David, "I.III.XVI. Of the reason of animals", A Treatise of
^ Immanuel Kant, Critique of Pure Reason; Critique of Practical
^ Michael Sandel, Justice: What's the Right Thing to Do?, New York:
Farrar, Straus and Giroux, 2009.
^ Kant, Immanuel; translated by James W. Ellington  (1993).
Grounding for the
Metaphysics of Morals 3rd ed. Hackett. p. 30.
^ See Velkley, Richard (2002), "On Kant's Socratism", Being After
Rousseau, University of Chicago Press and Kant's own first
preface to The Critique of Pure Reason.
^ Jürgen Habermas, Moral
Consciousness and Communicative Action,
Cambridge, MA: MIT Press, 1995.
^ Jürgen Habermas, The
Theory of Communicative Action:
Reason and the
Rationalization of Society, translated by Thomas McCarthy. Boston:
Beacon Press, 1984.
^ Nikolas Kompridis, Critique and Disclosure: Critical
Past and Future, Cambridge, MA: MIT Press, 2006. See also Nikolas
Kompridis, "So We Need Something Else for
Reason to Mean",
International Journal of Philosophical Studies 8:3, 271-295.
^ Charles Taylor, Philosophical Arguments (Harvard University Press,
1997), 12; 15.
^ Michel Foucault, "What is Enlightenment?", The Essential Foucault,
New York: The New Press, 2003, 43-57.
^ Douglas Hofstadter, Gödel, Escher, Bach, Vintage, 1979,
^ Aristotle, Complete Works (2 volumes), Princeton, 1995,
^ See this Perseus search, and compare English translations. and see
LSJ dictionary entry for λογικός, section II.2.b.
^ See the Treatise of
Nature of David Hume, Book I, Part III,
^ Locke, John (1824) , "XVII Of Reason", An Essay concerning
Understanding Part 2 and Other Writings, The Works of John Locke
in Nine Volumes, 2 (12th ed.), Rivington
^ Terrence Deacon, The Symbolic Species: The Co-Evolution of Language
and the Brain, W.W. Norton & Company, 1998,
^ Leviathan Chapter IV Archived 2006-06-15 at the Wayback Machine.:
"The Greeks have but one word, logos, for both speech and reason; not
that they thought there was no speech without reason, but no reasoning
Posterior Analytics II.19.
^ See for example
Ruth M.J. Byrne (2005). The Rational Imagination:
How People Create Counterfactual Alternatives to Reality. Cambridge,
MA: MIT Press.
De Anima III.i-iii; On
Memory and Recollection, On Dreams
Mimesis in modern academic writing, starting with Erich Auerbach, is
a technical word, which is not necessarily exactly the same in meaning
as the original Greek. See Mimesis.
^ Origins of the Modern
^ Jacob Klein A Commentary on the
^ Jacob Klein A Commentary on the
^ Origins of the Modern
^ "Introduction" to the translation of Poetics by Davis and Seth
Benardete p. xvii, xxviii
^ Davis is here using "poetic" in an unusual sense, questioning the
Aristotle between action (praxis, the praktikē) and
making (poēsis, the poētikē): "
Human [peculiarly human] action is
imitation of action because thinking is always rethinking. Aristotle
can define human beings as at once rational animals, political
animals, and imitative animals because in the end the three are the
Memory 450a 15-16.
^ Jacob Klein A Commentary on the
Aristotle Hist. Anim. I.1.488b.25-26.
^ Jacob Klein A Commentary on the
Meno p. 112
^ The Origins of the Modern
Mind p.173 see also A
Mind So Rare p.140-1
^ Jeffrey, Richard. 1991. Formal logic: its scope and limits, (3rd
ed.). New York: McGraw-Hill:1.
^ Walton, Douglas N. (2014). "Argumentation schemes for argument from
analogy". In Ribeiro, Henrique Jales. Systematic approaches to
argument by analogy. Argumentation library. 25. Cham; New York:
Springer Verlag. pp. 23–40. doi:10.1007/978-3-319-06334-8_2.
ISBN 9783319063331. OCLC 884441074.
^ Vickers, John (2009). "The Problem of Induction". The Stanford
Encyclopedia of Philosophy.
Metaphysics 981b: τὴν
ὀνομαζομένην σοφίαν περὶ τὰ πρῶτα
αἴτια καὶ τὰς ἀρχὰς ὑπολαμβάνουσι
πάντες: ὥστε, καθάπερ εἴρηται
πρότερον, ὁ μὲν ἔμπειρος τῶν
ὁποιανοῦν ἐχόντων αἴσθησιν εἶναι
δοκεῖ σοφώτερος, ὁ δὲ τεχνίτης τῶν
ἐμπείρων, χειροτέχνου δὲ ἀρχιτέκτων,
αἱ δὲ θεωρητικαὶ τῶν ποιητικῶν
μᾶλλον. English: "...what is called
Wisdom is concerned with
the primary causes and principles, so that, as has been already
stated, the man of experience is held to be wiser than the mere
possessors of any power of sensation, the artist than the man of
experience, the master craftsman than the artisan; and the speculative
sciences to be more learned than the productive."
Metaphysics 1009b ποῖα οὖν τούτων ἀληθῆ ἢ
ψευδῆ, ἄδηλον: οὐθὲν γὰρ μᾶλλον
τάδε ἢ τάδε ἀληθῆ, ἀλλ᾽ ὁμοίως. διὸ
Δημόκριτός γέ φησιν ἤτοι οὐθὲν
εἶναι ἀληθὲς ἢ ἡμῖν γ᾽ ἄδηλον. English
"Thus it is uncertain which of these impressions are true or false;
for one kind is no more true than another, but equally so. And hence
Democritus says that either there is no truth or we cannot discover
^ For example
Metaphysics 983a: ἐπεὶ δὲ
φανερὸν ὅτι τῶν ἐξ ἀρχῆς αἰτίων
δεῖ λαβεῖν ἐπιστήμην （τότε γὰρ
εἰδέναι φαμὲν ἕκαστον, ὅταν τὴν
πρώτην αἰτίαν οἰώμεθα γνωρίζειν）
English "It is clear that we must obtain knowledge of the primary
causes, because it is when we think that we understand its primary
cause that we claim to know each particular thing."
^ Example: Nicomachean
Ethics 1139b: ἀμφοτέρων δὴ τῶν
νοητικῶν μορίων ἀλήθεια τὸ ἔργον.
καθ᾽ ἃς οὖν μάλιστα ἕξεις ἀληθεύσει
ἑκάτερον, αὗται ἀρεταὶ ἀμφοῖν. English
The attainment of truth is then the function of both the intellectual
parts of the soul. Therefore their respective virtues are those
dispositions that will best qualify them to attain truth.
Plato Republic 490b: μιγεὶς τῷ ὄντι
ὄντως, γεννήσας νοῦν καὶ ἀλήθειαν,
γνοίη English: "Consorting with reality really, he would beget
intelligence and truth, attain to knowledge"
^ "This quest for the beginnings proceeds through sense perception,
reasoning, and what they call noesis, which is literally translated by
"understanding" or intellect," and which we can perhaps translate a
little bit more cautiously by "awareness," an awareness of the mind's
eye as distinguished from sensible awareness." "Progress or Return" in
An Introduction to Political Philosophy: Ten Essays by Leo Strauss.
(Expanded version of Political Philosophy: Six Essays by Leo Strauss,
1975.) Ed. Hilail Gilden. Detroit: Wayne State UP, 1989.
^ However, the empiricism of
Aristotle must certainly be doubted. For
Metaphysics 1009b, cited above, he criticizes people who
think knowledge might not be possible because, "They say that the
impression given through sense-perception is necessarily true; for it
is on these grounds that both
practically all the rest have become obsessed by such opinions as
Philosophy of History, p. 9, Dover Publications
Inc., ISBN 0-486-20112-0; 1st ed. 1899
^ Velkley, Richard (2002), "Speech. Imagination, Origins:
the Political Animal", Being after Rousseau:
Philosophy and Culture in
Question, University of Chicago Press
Rousseau (1997), "Preface", in Gourevitch, Discourse on the Origin
and Foundations of Inequality Among Men or Second Discourse, Cambridge
^ Velkley, Richard (2002), "Freedom, Teleology, and Justification of
Reason", Being after Rousseau:
Philosophy and Culture in Question,
University of Chicago Press
^ Plattner, Marc (1997), "
Rousseau and the Origins of Nationalism",
The Legacy of Rousseau, University of Chicago Press
^ Dawkins, Richard (2008-01-16). The God Delusion (Reprint ed.).
Mariner Books. ISBN 9780618918249. Scientists... see the fight
for evolution as only one battle in a larger war: a looming war
between supernaturalism on the one side and rationality on the other.
^ Strauss, Leo, "Progress or Return", An Introduction to Political
^ Locke, John (1824) , "XVIII Of
Faith and Reason, and their
distinct Provinces.", An Essay concerning
Understanding Part 2
and Other Writings, The Works of
John Locke in Nine Volumes, 2 (An
Understanding Part 2 and Other Writings) (12th
^ Plantinga, Alvin (2011-12-09). Where the Conflict Really Lies:
Science, Religion, and Naturalism (1 ed.). Oxford University Press.
^ Natural Signs and
Knowledge of God: A New Look at Theistic Arguments
(Reprint ed.). Oxford: Oxford University Press. 2012-12-15.
^ "Stephen Jay Gould, "Nonoverlapping Magisteria," 1997".
www.stephenjaygould.org. Retrieved 2016-04-06. To say it for all my
colleagues and for the umpteenth millionth time (from college bull
sessions to learned treatises): science simply cannot (by its
legitimate methods) adjudicate the issue of God's possible
superintendence of nature. We neither affirm nor deny it; we simply
can't comment on it as scientists.
^ Dawkins, Richard (2008-01-16). "4". The God Delusion (Reprint ed.).
Mariner Books. ISBN 9780618918249. This sounds terrific, right up
until you give it a moment's thought. You then realize that the
presence of a creative deity in the universe is clearly a scientific
hypothesis. Indeed, it is hard to imagine a more momentous hypothesis
in all of science. A universe with a god would be a completely
different kind of universe from one without, and it would be a
scientific difference. God could clinch the matter in his favour at
any moment by staging a spectacular demonstration of his powers, one
that would satisfy the exacting standards of science. Even the
infamous Templeton Foundation recognized that God is a scientific
hypothesis — by funding double-blind trials to test whether remote
prayer would speed the recovery of heart patients. It didn't, of
course, although a control group who knew they had been prayed for
tended to get worse (how about a class action suit against the
Templeton Foundation?) Despite such well-financed efforts, no evidence
for God's existence has yet appeared.
^ Moreland, J.P. "
Consciousness and the Existence of God: A Theistic
Argument". Routledge. Retrieved 2016-04-06.
^ "The Meaning of Life as Narrative: A New Proposal for Interpreting
Philosophy's 'Primary' Question - Joshua W. Seachris - Philo
Philosophy Documentation Center)". www.pdcnet.org. Retrieved
^ Three Rival Versions of Moral Enquiry: Encyclopaedia, Genealogy, and
Tradition (60067th ed.). University of Notre Dame Press. 1991-08-31.
^ Taylor, Charles (2007-09-20). A Secular Age (1st ed.). The Belknap
Press of Harvard University Press. ISBN 9780674026766.
Athens Met Jerusalem: An Introduction to Classical and
Thought (58760th ed.). IVP Academic. 2009-05-21.
^ Shestov, Lev (1968-01-01).
Athens and Jerusalem. Simon and
^ "Progress or Return" in An Introduction to Political Philosophy: Ten
Essays by Leo Strauss. (Expanded version of Political Philosophy: Six
Essays by Leo Strauss, 1975.) Ed. Hilail Gilden. Detroit: Wayne State
^ Bhagavad Gita, Sarvepalli Radhakrishnan: "
Hinduism is not just a
faith. It is the union of reason and intuition that can not be defined
but is only to be experienced."
^ Politics I.2.1252b15
^ Manktelow, K.I. 1999. Reasoning and Thinking (Cognitive Psychology:
Modular Course.). Hove, Sussex:
^ Johnson-Laird, P.N. & Byrne, R.M.J. (1991). Deduction.
^ Johnson-Laird, P.N. (2006). How we reason. Oxford: Oxford University
^ Byrne, R.M.J. (2005). The Rational Imagination: How People Create
Counterfactual Alternatives to Reality. Cambridge, MA: MIT Press
^ Demetriou, A. (1998). Cognitive development. In A. Demetriou, W.
Doise, K.F.M. van Lieshout (Eds.), Life-span developmental psychology
(pp. 179-269). London: Wiley.
^ Costantini, Stefania (2002), "Meta-reasoning: A Survey", Lecture
Notes in Computer Science, 2408/2002 (65): 253–288,
^ Mercier, Hugo; Sperber, Dan (2011). "Why Do
Humans Reason? Arguments
for an Argumentative Theory". Behavioral and Brain Sciences. 34 (2):
^ Mercier, Hugo; Sperber, Dan (2017). The Enigma of Reason. Cambridge:
Harvard University Press. ISBN 978-0-674-36830-9.
Look up reason in Wiktionary, the free dictionary.
Wikiquote has quotations related to: Reason
Reason at PhilPapers
Beer, Francis A., "Words of Reason", Political
(Summer, 1994): 185-201.
Gilovich, Thomas (1991), How We Know What Isn't So: The Fallibility of
Reason in Everyday Life, New York: The Free Press,
Tripurari, Swami, On
Faith and Reason, The Harmonist, May 27, 2009.
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