Here is a philosophical puzzle that should trouble every historian: you cannot directly access the thoughts of the person sitting next to you right now. You infer their mental states from behavior, speech, and expression. You assume their inner life resembles yours. But you cannot know it in the way you know your own thoughts. This is the classic problem of other minds—and historians face it in its most extreme form.

When we study the past, we encounter minds separated from us not only by the barrier that divides all consciousness from consciousness, but by centuries of cultural change, linguistic evolution, and conceptual transformation. We read Cicero's letters and believe we understand his political anxieties. We interpret medieval wills and think we grasp pious intentions. We analyze revolutionary pamphlets and claim insight into popular consciousness. But what epistemic warrant do we have for these claims? How can we know what anyone in the past actually thought?

This question strikes at the heart of historical practice. Much of what historians do—explaining decisions, attributing motives, reconstructing mentalities—depends on claims about past mental states. If such claims are philosophically groundless, then vast territories of historical knowledge become suspect. R.G. Collingwood argued that all history is the history of thought, that understanding the past means re-thinking the thoughts of historical actors. But is such re-thinking genuinely possible, or merely a sophisticated projection of our own minds onto alien materials?

The philosophical problem of other minds challenges even our knowledge of contemporaries. We observe behavior and infer mental states through analogy with our own experience. When someone winces, we infer pain because we wince when pained. This inference, while practically indispensable, rests on unprovable assumptions. We cannot step outside our own consciousness to verify that others possess inner lives at all, let alone that their experiences resemble ours.

Historians face this general problem in an intensified form. The minds we study are not merely other—they are absent. We cannot observe behavior directly; we work only with its traces. The medieval peasant whose mental world we seek to reconstruct left no interview, no diary, perhaps no words at all. We have only material remains, institutional records, and elite representations of popular belief. The evidential base for our inferences is radically impoverished compared to everyday mind-reading.

Beyond absence lies alterity—radical difference. Contemporary mind-reading assumes shared conceptual frameworks, emotional repertoires, and forms of life. But historical actors may have inhabited mentalities so different from ours that analogical inference fails. Did ancient Greeks experience color as we do? Did medieval Christians genuinely believe in the physical reality of demonic possession, or were such claims rhetorical? The principle of charity urges us to interpret others as rational, but rationality itself may be historically variable.

This double distance—temporal absence compounded by cultural alterity—creates what some philosophers call the hermeneutic gap. We must bridge not only the gulf between one consciousness and another, but the chasm between entire forms of life. The concepts available to a twelfth-century monk for understanding his own mental states may be incommensurable with our psychological vocabulary. When we translate his experience into our terms, do we understand him or domesticate him?

The epistemic challenge is severe. If we cannot verify our interpretations of minds present and accessible, how can we justify claims about minds absent and alien? Some historians respond by limiting claims to observable behavior—what people did rather than what they thought. But this restriction guts historical explanation. Actions without intentions are mere movements; events without meaning are bare occurrences. To do meaningful history, we must venture claims about consciousness.

Takeaway

Historical knowledge of past minds faces a compounded epistemic challenge: we cannot directly access any consciousness, and historical minds are additionally separated by absence and cultural difference that may make analogical inference unreliable.

Historians' primary access to past minds comes through behavior—but behavior always underdetermines the mental states that produced it. The same action can flow from radically different intentions. A medieval lord endowing a monastery might act from genuine piety, social competition, anxiety about salvation, desire to provide for a younger son, or strategic calculation about political alliances. The endowment charter tells us what he did; it cannot tell us what he thought.

Written sources seem to offer more direct access to thought, but they introduce their own problems. Texts are crafted performances, shaped by genre conventions, audience expectations, and rhetorical purposes. When Petrarch writes letters expressing melancholy, is he reporting inner states or constructing a literary persona? The conventions of epistolary self-presentation in fourteenth-century Italy differ from ours. We cannot simply read through the text to the mind behind it.

Material culture provides another evidential avenue, but the same indeterminacy applies. Grave goods may indicate belief in afterlife, social display, or conventional practice unreflectively followed. The artifact is mute—it cannot tell us what it meant to those who made and used it. We impose interpretations that may reveal more about our assumptions than about past mentalities. Archaeological inference about belief is particularly precarious.

Even when sources explicitly articulate beliefs, we face the problem of sincerity and self-knowledge. Did people believe what they said they believed? Could they accurately report their own mental states? Modern psychology reveals how poorly we understand our own motivations, how retrospective rationalization shapes memory, how social desirability warps self-report. These distortions presumably afflicted historical actors too, compounded by different cultural norms of self-presentation.

The methodological response has been triangulation—using multiple source types to constrain interpretation. If behavior, expressed belief, and material culture all point toward the same mental state, our inference gains credibility. But convergence proves less than we might hope. All our sources are produced by the same culture and may share the same systematic biases. Medieval sources consistently attribute pious motives because piety was the acceptable public explanation; this consistency doesn't prove genuine piety.

Takeaway

Every type of historical evidence—actions, texts, artifacts—underdetermines the mental states behind it, and even convergent sources may share systematic biases that make our inferences about past thought inherently provisional.

Acknowledging the problem of other minds need not paralyze historical practice. Philosophers have developed sophisticated responses that, while not solving the problem, provide methodologically defensible approaches to past mentalities. The key is moving from certainty to warranted interpretation—acknowledging uncertainty while maintaining meaningful claims.

Collingwood's method of re-enactment offers one strategy. The historian reconstructs the problem-situation facing a historical actor, then thinks through possible responses given available concepts and constraints. This doesn't require identical mental content—only the ability to grasp how someone reasoning with different assumptions might have thought. We understand Caesar's crossing of the Rubicon not by replicating his exact mental state but by grasping the logic of his situation.

Contextual interpretation provides another approach. Rather than claiming access to individual minds, we reconstruct the conceptual repertoire available within a culture. We can know what concepts, categories, and forms of reasoning were available even when we cannot know how specific individuals deployed them. The mental toolkit matters more than the specific thoughts it enabled. This shifts focus from psychology to cultural history.

The principle of defamiliarization counters our tendency to project modern mentalities onto the past. By actively seeking difference rather than similarity, we resist the temptation to find our own minds wherever we look. When sources seem immediately comprehensible, that's often when we've most thoroughly misunderstood—imposing familiarity where strangeness should give us pause. Good historical interpretation should surprise us.

Finally, honest historians practice what might be called epistemic humility—marking the difference between well-supported inference and speculative interpretation, acknowledging where evidence runs out, and presenting competing interpretations rather than false certainty. The goal is not to overcome the problem of other minds but to work responsibly within its constraints, making the most defensible claims possible while remaining honest about their provisional character.

Takeaway

Rather than claiming impossible certainty about past minds, rigorous historical practice involves reconstructing problem-situations, mapping available conceptual repertoires, actively seeking unfamiliarity, and honestly marking the boundaries of warranted interpretation.

The problem of other minds cannot be solved—not for our contemporaries, and certainly not for historical actors separated from us by centuries of change. This is not a counsel of despair but an invitation to intellectual honesty. We can still write meaningful history about what people thought and believed, but we must do so with appropriate epistemological modesty.

The strategies developed within hermeneutic philosophy—re-enactment, contextual reconstruction, defamiliarization, epistemic humility—do not give us certainty. They give us something more valuable: disciplined interpretation. They help us make the best possible inferences while acknowledging their provisional character and remaining open to revision.

Perhaps the deepest lesson is that understanding other minds—past or present—is never complete. It is always an ongoing practice, a reaching across the gulf of consciousness that can be done more or less well but never definitively achieved. Historical knowledge of past mentalities remains genuinely possible, genuinely valuable, and genuinely uncertain.