Reason

===Reason versus truth, and "first principles"===
{{See also|Truth|First principle|Nous}}
Since [[classical antiquity]] a question has remained constant in philosophical debate (sometimes seen as a conflict between [[Platonism]] and [[Aristotelianism]]) concerning the role of reason in confirming [[truth]]. People use logic, [[deductive reasoning|deduction]], and [[inductive reasoning|induction]] to reach conclusions they think are true. Conclusions reached in this way are considered, according to Aristotle, more certain than sense perceptions on their own.<ref>{{cite book|author=Aristotle|title=[[Metaphysics (Aristotle)|Metaphysics]]|at=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0051%3Abook%3D1%3Asection%3D981b 981b]|language=grc|quote=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.|trans-quote=...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.}}</ref> 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 better.<ref>{{cite book|author=Aristotle|title=[[Metaphysics (Aristotle)|Metaphysics]]|at=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0051%3Abook%3D1%3Asection%3D1009b 1009b]|language=grc|quote=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.|trans-quote=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 it.}}</ref>

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 {{transliteration|grc|[[Arche|archai]]}}, "starting points",<ref>{{cite book|author=Aristotle|title=[[Metaphysics (Aristotle)|Metaphysics]]|at=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0051%3Abook%3D1%3Asection%3D983a 983a]|language=grc|quote=ἐπεὶ δὲ φανερὸν ὅτι τῶν ἐξ ''ἀρχῆς'' αἰτίων δεῖ λαβεῖν ''ἐπιστήμην'' (τότε γὰρ εἰδέναι φαμὲν ἕκαστον, ὅταν τὴν ''πρώτην'' αἰτίαν οἰώμεθα ''γνωρίζειν'')|trans-quote=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.}}</ref> and the faculty used to perceive them is sometimes referred to in Aristotle<ref>{{cite book|author=Aristotle|title=[[Nicomachean Ethics]]|at=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0053%3Abekker+page%3D1139a 1139b]|language=grc|quote=ἀμφοτέρων δὴ τῶν ''νοητικῶν'' μορίων ἀλήθεια τὸ ἔργον. καθ᾽ ἃς οὖν μάλιστα ἕξεις ἀληθεύσει ἑκάτερον, αὗται ἀρεταὶ ἀμφοῖν|trans-quote=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.}}</ref> and Plato<ref>{{cite book|author=Plato|title=[[Republic (Plato)|Republic]]|at=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0167%3Abook%3D6%3Asection%3D490b 490b]|language=grc|quote=μιγεὶς τῷ ὄντι ὄντως, γεννήσας νοῦν καὶ ἀλήθειαν, γνοίη|trans-quote=Consorting with reality really, he would beget intelligence and truth, attain to knowledge}}</ref> as {{transliteration|grc|[[nous]]}} which was close in meaning to ''awareness'' or ''[[consciousness]]''.<ref name=StraussProgress>{{cite book|quote=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.|chapter=Progress or Return|title=An Introduction to Political Philosophy: Ten Essays by Leo Strauss|first=Leo|last=Strauss|author-link=Leo Strauss|orig-year=1975|editor-first=Hilail|editor-last=Gilden|location=Detroit|publisher=Wayne State University Press|year=1989}}</ref>

[[Empiricism]] (sometimes associated with Aristotle<ref>However, the empiricism of Aristotle must certainly be doubted. For example in ''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 [[Empedocles]] and Democritus and practically all the rest have become obsessed by such opinions as these."</ref> but more correctly associated with [[Great Britain|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, within which certain people can directly discover 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]], [[Maimonides]], [[Aquinas]], and [[Hegel]] are sometimes said{{By whom|date=September 2023}} 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 Aquinas]] and [[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."<ref>{{cite book|first=G.W.F.|last=Hegel|title=[[Lectures on the Philosophy of History|''The Philosophy of History'']]|page=9|publisher=Dover Publications Inc.|isbn=0486201120|year=1956|orig-year=1837}}</ref>

Since the 17th century [[rationalist]]s, reason has often been taken to be a [[subjectivity|subjective faculty]], or rather the unaided ability ([[pure reason]]) to form concepts. For [[Descartes]], [[Spinoza]], and [[Gottfried Wilhelm Leibniz|Leibniz]], this was associated with [[mathematics]]. [[Immanuel Kant|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.