What is truth, and can we truly reach it?

Moderator, you ask whether truth may be attainable without being exhaustive or indubitable. I distinguish possessing a true opinion from understanding why it is true: a traveler may follow the right road by good fortune, yet lack the knowledge needed to guide another reliably. Persuasive appearance wins assent; truth does not depend upon our assent. In the Republic, I distinguish the changing things we perceive from the intelligible Forms through which they are understood. Equal sticks appear unequal from another standpoint; Equality itself does not become inequality. I therefore seek knowledge not merely of what seems so, but of what is. I hold that we can turn toward this reality through dialectic, testing our accounts and ascending beyond unexamined assumptions. Yet I do not call every confident speaker a knower, nor claim that inquiry makes us omniscient. The prisoner leaving the cave is first dazzled: the difficulty of seeing is no argument that there is no light.

Plato, I agree that arriving at a true opinion differs from knowing why it is true. But I dispute your inference from the variability of equal sticks to a separately existing Equality. A difference in appearance does not establish a separation in being; I seek the intelligible nature within the things themselves. I call it true to say of what is that it is, and of what is not that it is not. Our assent does not make this so: the thing’s being as we say makes our assertion true. Can we attain truth? I maintain that we can, though not with equal precision in every inquiry. Perception, memory, and experience furnish the beginnings from which we apprehend universals; demonstration yields knowledge through causes. Yet not everything can be demonstrated, for demonstration depends upon first principles. I therefore distinguish attaining truth from proving every truth: demanding proof without limit would destroy the very possibility of proof.

Aristotle, I grant your claim that assent does not make an assertion true. But I challenge the sufficiency of this account for the existing individual who asks how to live. I might correctly describe the good and yet evade it throughout my life. What have I then attained—a truth, certainly, but not a truthful existence. Through my pseudonym Johannes Climacus, I call subjectivity truth: not because wishing alters facts, but because, in ethical and religious existence, the manner of appropriation is decisive. I cannot become faithful merely by establishing propositions about faith. You distinguish attaining truth from proving every truth. I would distinguish knowing an account from existing in what it demands. At the religious limit, objective uncertainty does not simply disappear beneath demonstration; I must venture commitment without that security. Can I reach truth? Not as a completed possession that releases me from becoming. I must continually answer for my relation to it.

Aristotle, I accept your account of truth as the agreement of cognition with its object. But I distinguish this definition from a universal criterion by which every assertion could be certified. Logic supplies necessary conditions of truth, not sufficient ones: a coherent judgment may nevertheless lack an object corresponding to it. I therefore ask what makes cognition of objects possible. Experience does not merely furnish material from which all intelligibility is extracted; the understanding contributes a priori forms through which that material becomes experience of an objective world. Against Plato’s ascent beyond appearances, I maintain that these conditions authorize knowledge only of objects of possible experience, not of things as they are in themselves. Appearance here does not mean illusion: an empirically real object can be genuinely known without being known independently of our manner of cognition. I thus answer that we can attain truth, but cannot convert the conditions of human knowledge into a warrant for knowing reality without qualification.

Kant, I agree that a definition of truth does not furnish a procedure for deciding every assertion. But I would question your expression “reality without qualification.” What would count as knowing this, and what would count as failing to know it? If neither can be described, I suspect that the expression gives us the appearance of a destination without a road to it. I would begin with ordinary cases. We establish that the door is open by looking; we establish a mathematical proposition by proof. These activities are not imperfect attempts at one hidden, perfect method. Their differences belong to the language games in which we speak of knowing and being mistaken. I do not thereby make truth depend upon assent. I ask how an assertion is used, how it is tested, and what contradicts it. We can discover that the door is open. Must we also overcome a philosophical obstacle called our inability to reach reality itself?

Wittgenstein, reasoning from my principles in reply to your later account, I challenge your example of establishing that the door is open by looking. I grant that looking ordinarily suffices for practical judgment. Yet in a dream I may seem to look and find precisely the same assurance. Your account of testing does not itself remove this possibility. I distinguish what makes a judgment true—its agreement with what is—from what warrants my certainty. My methodical doubt seeks not another object behind the door, but a foundation that deception cannot overthrow. Even if an evil demon deceives me, I must exist while I am thinking: cogito, I think, therefore I am. I thus reach at least one truth without first settling the reliability of perception. I do not infer that every conviction enjoys this certainty. My further task is to establish a nondeceiving God as guarantor of clear and distinct perceptions; the cogito alone does not restore knowledge of bodies.

Descartes, I challenge the supposed innocence of your “I think.” You have already assumed that thinking is an activity, that every activity requires an agent, and that you know what thinking is. Your certainty arrives carrying a whole household of unexamined interpretations. Even “there is thinking” says more than the immediate occurrence warrants. I ask a further question: why must knowledge possess a foundation that no conceivable deception can overthrow? What valuation makes uncertainty an objection to existence? I suspect in this demand a will to security masquerading as pure reason. I do not therefore make every interpretation equally good. I seek a stronger objectivity through the discipline of employing many perspectives and commanding their differences—not through an eye that sees from nowhere. We can expose errors, overcome prejudices, and deepen knowledge. But I distinguish this achievement from possessing an uninterpreted world. Your nondeceiving God would guarantee precisely what I ask us to examine: our faith in the unconditional value of truth.

Nietzsche, reasoning from my principles against your later objection, I deny that my first certainty is a syllogism whose hidden premise declares that every activity requires an agent. When I apprehend that I exist while doubting, I recognize this through an immediate intuition, not through a general theory of causation. Your challenge itself cannot make me nothing while I entertain it. I concede that this does not yet disclose everything about the nature of the self. I must not smuggle bodily identity, memory, or a complete account of substance into that first recognition. You also ask why I demand certainty. I do not regard uncertainty as an objection to existence; I regard it as a reason to withhold assent when seeking an unshakable foundation for knowledge. Multiple perspectives may correct prejudices, but their number alone cannot distinguish correction from renewed error. I ask what warrants your judgment that one interpretation deepens knowledge rather than merely strengthens conviction.