When historians explain the French Revolution, they invoke economic crisis, Enlightenment ideology, weak monarchy, crop failures, and the ambitions of particular individuals. But what kind of explanation is this? The question appears simple until you press on it: are these causes in the same sense that striking a match causes flame? The philosophical problem of historical causation has occupied methodologists for over a century, and the stakes extend far beyond academic debate. How we conceptualize historical causation shapes what we look for, what we find significant, and ultimately what stories we tell about the past.

The difficulty begins with the uniqueness of historical events. A chemist can replicate an experiment to isolate variables; a historian cannot re-run the French Revolution while holding constant everything except bread prices. This asymmetry between natural science and historical inquiry raises fundamental questions about whether historical explanation can ever achieve the logical rigor of scientific explanation, or whether it represents an entirely different cognitive enterprise requiring its own philosophical foundation.

What follows examines three interconnected problems in historical causation. First, the plurality of causal types that historians invoke and how these different causes relate to one another. Second, the long-running debate about whether historical explanation requires general laws analogous to those in natural science. Third, the role of counterfactual reasoning in establishing causal significance. Each problem illuminates the gap between how things came about—the narrative sequence of events—and why they happened—the deeper explanatory claim that these antecedent conditions made the outcome intelligible.

Historians routinely distinguish between different types of causes without always making explicit what logical work each type performs. Necessary conditions are factors without which the event could not have occurred: without gunpowder, no firearms revolution; without the printing press, no Protestant Reformation as we know it. Yet necessary conditions alone explain nothing—oxygen is necessary for fires but does not explain why this building burned on this night. The necessity claim establishes a minimal logical relationship but leaves the explanatory heavy lifting undone.

Sufficient conditions would guarantee the outcome, but historical events rarely if ever have sufficient conditions identifiable in advance. No configuration of factors made World War I inevitable in any strict logical sense. What historians often mean when they speak of sufficient conditions is something weaker: a confluence of factors that made the outcome highly probable or overdetermined. The distinction matters because it separates logical necessity from probabilistic judgment, and historians frequently slide between these without acknowledgment.

The contrast between proximate triggers and underlying structural factors introduces temporal and analytical depth. The assassination of Archduke Franz Ferdinand triggered the war; the alliance system, imperial rivalries, and nationalist movements constituted the underlying structure that made such a trigger explosive. But which provides the genuine explanation? Structuralists argue that without the underlying tensions, the assassination would have been a diplomatic incident, not a world war. Yet the structural factors had existed for years without producing war—something had to actualize the potential.

This plurality creates what philosophers call the problem of causal selection. Any historical event has countless necessary conditions—including the existence of the universe, the evolution of human beings, and the invention of agriculture. Historians select from this infinite regress based on pragmatic considerations: what is unusual, what was subject to human agency, what connects to broader patterns of interest. The selection criteria reveal the historian's theoretical commitments and explanatory interests rather than any objective causal hierarchy.

R.G. Collingwood argued that historical causes are fundamentally different from natural causes because they involve human thought and intentional action. The cause of Caesar crossing the Rubicon was his decision, his reasoning about political circumstances. This internalist view shifts attention from external conditions to the logic of historical agents' thinking. Critics respond that Collingwood's approach cannot handle structural causation—no individual decided to create capitalism or trigger demographic transitions. The plurality of causal types may reflect genuinely different modes of historical determination rather than mere analytical convenience.

Takeaway

When evaluating historical explanations, ask what type of cause is being invoked—necessary condition, probable contributor, trigger, or structural factor—since each carries different logical weight and explains different aspects of why events unfolded as they did.

In 1942, philosopher Carl Hempel proposed that all genuine explanation follows a single logical pattern: the deductive-nomological model. To explain an event is to show that it follows deductively from general laws plus initial conditions. Explaining why water freezes means showing that given the temperature (initial condition) and the laws of thermodynamics, freezing necessarily follows. Hempel argued that historical explanation is no different—historians implicitly invoke general laws about human behavior, even when they do not state them explicitly.

The implications were radical. If Hempel was right, then historical explanation is logically identical to scientific explanation, merely less rigorous. When a historian explains revolutions by citing economic grievances, they implicitly invoke a general law: whenever economic grievances reach a certain threshold under certain conditions, revolutionary activity becomes probable. The historian's task would be to make these implicit generalizations explicit and test them against evidence. History would become a nomothetic discipline, seeking covering laws rather than merely narrating particular sequences.

Critics attacked from multiple directions. William Dray argued that historical explanation proceeds by showing how an action made sense given the agent's beliefs and circumstances, not by subsuming it under psychological laws. We explain Caesar's crossing the Rubicon by reconstructing his practical reasoning, not by invoking laws about how ambitious generals behave. This rational explanation model preserves the distinctiveness of historical understanding while denying that it requires covering laws.

Others noted that the general laws Hempel's model requires are either trivially true or empirically false. The law that revolutions occur when grievances are severe enough is circular—we measure severity by whether revolution occurred. More substantive generalizations about revolutionary conditions face immediate counterexamples. France had grievances in 1789 and revolution followed; similar or worse conditions elsewhere produced only reform or repression. The specificity of historical causation seems to resist the generality that covering laws demand.

The debate ultimately concerns whether historical knowledge is fundamentally continuous with or discontinuous from natural science. Narrativists like Louis Mink and Hayden White argued that historical understanding is constitutively narrative: we understand the past by following a story, not by subsuming events under laws. The meaning of historical events emerges from their place in a temporal sequence, their connection to what came before and after. This narrative comprehension may be a distinct cognitive mode irreducible to the deductive logic Hempel privileged. The covering law debate remains unresolved because it connects to deep disagreements about the unity of knowledge and the nature of understanding itself.

Takeaway

The covering law debate exposes a fundamental tension: treating history as science requiring general laws versus understanding it as interpretive reconstruction of meaningful human action—a tension that shapes whether we seek patterns or comprehend particulars.

To claim that X caused Y implies that without X, Y would not have occurred—or would have occurred differently. This counterfactual dependency is built into causal language, yet historians have traditionally been suspicious of counterfactual reasoning. Speculating about what would have happened if Napoleon had won at Waterloo seemed like parlor games rather than serious scholarship. E.H. Carr dismissed counterfactuals as a mere parlor game with no place in rigorous historical analysis. Yet philosophers of causation have shown that counterfactual thinking is not optional: it is already embedded in every causal claim historians make.

When a historian argues that the printing press caused the Reformation, they implicitly claim that without the printing press, the Reformation would not have occurred, or would have occurred very differently. Making the counterfactual explicit disciplines the causal reasoning. What exactly would have been different? Would there have been no challenge to Catholic authority, or merely a different challenge? Would reform ideas have spread more slowly, remained regional, or been suppressed entirely? These questions force precision about what causal work the printing press actually performed.

The methodological challenge is constraining counterfactual speculation so that it remains historically responsible rather than descending into fantasy. Minimal rewrite counterfactuals change one factor while holding as much else constant as possible. This approach asks what would have happened if the Archduke's driver had not taken a wrong turn, not what would have happened if humans had evolved without aggression. The discipline lies in tracing the consequences of the minimal change through the historical situation as it actually was, using our knowledge of how similar situations have unfolded.

Critics argue that counterfactual reasoning cannot escape speculation because we can never know what would have happened. But this objection proves too much—it would invalidate all causal claims, not just explicitly counterfactual ones. Historical causation necessarily involves claims about unrealized possibilities. The question is not whether to engage in counterfactual reasoning but how to do so responsibly. Evidence about parallel cases, knowledge of structural constraints, and sensitivity to the range of historically plausible alternatives all discipline the enterprise.

Counterfactual analysis also reveals the difference between causal significance and moral responsibility. The Archduke's driver making a wrong turn may have been causally necessary for the assassination, but attributing causal significance to this factor does not assign blame to the driver. Identifying causes is an explanatory activity distinct from distributing praise and blame. This distinction is frequently collapsed in popular historical argument, where establishing that someone caused an outcome is treated as equivalent to holding them responsible. Philosophical analysis of counterfactuals helps separate these logically distinct questions and clarifies what kind of knowledge causal claims actually provide.

Takeaway

Counterfactual reasoning is not idle speculation but the implicit logic of all causal claims—making it explicit by asking precisely what would have differed reveals whether we have genuine explanation or merely temporal sequence.

The gap between how things came about and why they happened marks a fundamental tension in historical inquiry. Narrative shows sequence and connection; causal explanation claims that certain antecedents made certain outcomes intelligible or even necessary. The philosophical problems examined here—causal plurality, the covering law debate, and counterfactual reasoning—do not admit of easy resolution. They reflect genuine complexity in the nature of historical determination and the cognitive operations involved in understanding the past.

What emerges is not skepticism about historical causation but sophistication about its different modes and limits. Historians invoke necessary conditions, structural factors, triggering events, and human decisions. Each type of cause does different explanatory work and requires different evidential support. The choice among them is never merely technical; it reflects theoretical commitments about what kind of understanding historical inquiry provides.

For practicing historians, philosophical reflection on causation serves a critical function: it makes visible the assumptions built into explanatory choices and opens them to examination. The question why did this happen? is never innocent. It always presupposes a framework for thinking about causation that shapes what counts as an answer.