Relation to truth· Belief and knowledgedifficulty
Justification of belief
What makes a belief justified?
From pseudo-sciences to rumours, countless beliefs present themselves as justified: what remains is to know what that warrant rests on, first certainties, the agreement of the whole, or methods that have proven themselves. Depending on the answer, we draw the line between knowledge and what merely looks like it in a different place.
Foundationalism
5Knowledge rests on basic beliefs, immediately certain, that need no others to justify themselves: everything else is built upon them, like a building on its foundations.
Explore this position →Descartesexplicit
The project of the Meditations on First Philosophy is expressly foundationalist: to tear down every doubtful opinion and rebuild knowledge on a single unshakeable first principle, the cogito, whose certainty then supports the whole edifice. Knowledge rests on indubitable foundations, not on the mere coherence of a web of beliefs.
Meditations on First Philosophy, I-II
Rationalismexplicit
Every justification, on pain of an infinite regress, must come to rest on principles that depend on no other: rationalism settles the matter by holding that these stopping points are first truths grasped with self-evidence by intellectual intuition, not ever-revisable sense data. This is a thoroughgoing foundationalism: knowledge is built like a deductive edifice, from axioms toward theorems, each step preserving the certainty of the last. Against , which backs justification onto singular impressions unable to ground the necessary, rational self-evidence alone can serve as the base, because it shows itself indubitable in the very act of being conceived.
Descartes, Meditations; Spinoza, Ethics
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Husserlinferable
Husserl is resolutely foundationalist: he seeks a last and absolute foundation of knowledge, a base of originary evidences on which all the rest can be built without circle or regress. This bedrock is neither a coherence of the system nor the reliability of a process, but giving evidence, the thing showing itself in person. Phenomenology means to be "first philosophy", the discipline of principles that justifies the other sciences while borrowing nothing from them, which places Husserl with the Cartesian quest for an absolute beginning rather than with a web of mutually supporting beliefs.
Cartesian Meditations, First-Second Meditation · Ideas I, §24
Spinozainferable
The Ethics is demonstrated "in the geometrical manner": all knowledge is deduced from first definitions and axioms, and an adequate idea carries its certainty within itself, a true idea being its own standard. This is a rationalist foundationalism.
Ethics, I; Treatise on the Emendation of the Intellect
Lockeinferable
All our knowledge comes from experience: it is built up from simple ideas received through sensation and reflection, to which the mind can add nothing. These simple ideas form the base on which knowledge is erected, an empiricist foundationalism.
An Essay Concerning Human Understanding, II
Coherentism
1No belief is justified on its own: it is justified by its place in a coherent whole, where each supports the others. An idea holds if it fits without contradiction into the entire web of our experience, with no ultimate foundation.
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Charles Sanders Peirceinferable
Peirce attacks head-on 's : one cannot doubt at will nor feign a doubt one does not have, real doubt is born of a surprise, a jolt of experience, never of a decision. He likewise rejects intuition, that supposed first cognition deriving from no other: all thought is inference from prior thoughts, sign referring to other signs. As a result, justification rests on no indubitable basic belief, but on the holding of the whole: knowledge is a cable whose strength comes from the multitude of intertwined fibres, not a chain as weak as its frailest link. This coherentist bent is doubled by a reliabilist strand, since what validates a belief is also the tested reliability of the method that produced it.
Questions Concerning Certain Faculties Claimed for Man (1868) · Some Consequences of Four Incapacities (1868)
Reliabilism
1A belief is justified if it is produced by a reliable process, perception, memory, sound reasoning, even if the one who holds it could not prove it. What matters is not being able to justify it, but having been formed in the right way.
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Baconinferable
Before building, Bacon means to purge the mind of what distorts it: these are the four (), the systematic biases of knowledge. Idols of the tribe, inherent in the species, which lends nature more order than it has; idols of the cave, proper to each individual and his history; idols of the marketplace, slipped into thought by language and ill-made words; idols of the theatre, the received philosophical systems taken as so many fables played out on a stage. A belief is therefore justified not by tracing it back to a first indubitable intuition, but by the reliability of the process that produces it, once the mind is scoured of its idols and submitted to the experimental rule. The warrant lies on the side of method, not of an inner foundation.
Novum Organum, I, §38-68 (the idols)
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- Descriptive SituationShould you believe it?
Faced with a claim we cannot check for ourselves, what would make believing it justified: being able to trace it to first-hand evidence, its coherence with all we already know, or the reliability of the source it comes from?
a claim received
Sub-problems to deepen this axis's discussion
- DescriptiveThe chain of reasons
Every belief rests on a reason, which rests on another: either the chain stops at beliefs that justify themselves, or it closes into a circle where each supports the others, or it runs off to infinity. These three exits are exactly the three ways of answering "what justifies a belief?".
the chain of reasons - DescriptiveAre there first evidences?
Foundationalism assumes beliefs that justify themselves, a perception or an evidence so immediate it needs no other. But do we ever perceive anything pure? Even "I see red" already draws on concepts, memory, learning: if there is no truly first given, what does the whole edifice rest on?
a basic belief - DescriptiveCoherent, yet false?
A set of beliefs can be perfectly coherent and yet wholly cut off from reality: a well-built tale, a systematic delusion, a conspiracy theory that explains everything and absorbs every objection. If coherence is not enough to touch the world, must beliefs not also answer to something outside, to the experience that contradicts them?
a coherent system - DescriptiveMust you be able to justify yourself?
To be justified, must one be able to give one's reasons, or is it enough that the belief was well produced? An expert "senses" the right diagnosis without being able to explain it; conversely, we would hesitate to say he knows, the one whose hunches hit the mark through a power he knows nothing of. Does justification lie in the reasons one can give, or in the reliability of the process, even when invisible to the one who exercises it?
a well-formed belief - DescriptiveTrue by luck
The classic definition holds knowledge to be a belief that is both true and justified. Yet one can believe something for good reasons, and have it be true, without thereby knowing it: the stopped clock we glance at just at the hour it still shows, the rock we take from afar for a sheep while a real one grazes behind it. The belief is true and justified, but it hits the mark by accident. Must we then redefine what knowledge is, or tighten what we are entitled to demand of a justification, until it links belief to truth otherwise than by luck?
a belief true by luck
Related problems to broaden toward other axes
- PrescriptiveEpistemicHave we the right to believe?
Beyond what makes a belief justified, is it permissible to believe without sufficient evidence, or is it a fault, toward oneself as toward others? The question of warrant extends into that of the duty of belief.
the act of believing - DescriptiveThe post-truth age
The whole question of justification presupposes that there is a truth to reach. But when "alternative facts" and indifference to truth take hold, is it truth itself that wavers, or only our honesty in seeking it?
truth as the aim - DescriptiveJustify, how far?
Every reason rests on another reason: does the chain stop at a foundation, turn in a circle, or run off to infinity? This is the skeptic's lever.
the chain of reasonsRelation to certainty
Reasoning should not form a chain which is no stronger than its weakest link, but a cable whose fibers may be ever so slender, provided they are sufficiently numerous and intimately connected.Charles Sanders Peirce · Some Consequences of Four Incapacities (1868)
Four kinds of idols beset the human mind.Bacon · Novum Organum, I, §39