Testing Historical Hypotheses.

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One implication of the lack of direct access to the past concerns the testability of historical hypotheses. The historian cannot perform experiments on his work like can a scientist. However, one may make the argument that even the historian’s hypotheses are testable through examining its logical consistency as well as its ability to explain historical evidence.

Rather, the key question revolves around how the historian can actually apply his test. It may be the case, as some have noted, that he applies such a test in a similar way as does the scientist. For example, there appears to be congruence between a model, the hypothetico-deductive model, that one adopts in the sciences that may do well in the historians task. This model formulates a hypothesis in a form that could conceivably be falsified by a test on observable data (1). Thus, the scientist invents a hypothesis to provide an explanation of the available facts and then infers from the hypothesis specific conditions that would either confirm or disprove the hypothesis.

The historian is able to follow this same method since he is able to reconstruct a picture of the past that constitutes his hypothesis. Subsequently, he is then able to deduce certain conditions from his hypothesis that will either confirm or disprove his hypothesis. He then evaluates which conditions exist through, not scientific experiments as scientist perform, but by historical evidence. As the once influential historian and archaeologist Robin Collingwood explained, “The historian’s picture of the past stands in a peculiar relation to something called evidence. The only way in which the historian can judge of its truth is by considering this relation” (2). The historian’s hypothesis, explained Collingwood, must be corroborated by the evidence, for example, archaeological evidence. William Debbins, a writer on matters pertinent to the philosophy of history, notes that “By treating coins, pottery, weapons, and other artifacts as evidence the historian raises his study to the level of a science. What happened in the past is what the evidence indicates as having happened” (3).

Moreover, beyond the hypothetico-deductive model one may employ the more contemporary model of inference to the best explanation. Gilbert Herman, back in the mid 1960s, was the mind behind this deductive reasoning; he explains that “In making this inference one infers, from the fact that a certain hypothesis would explain the evidence, to the truth of that hypothesis. In general, there will be several hypotheses which might explain the evidence, so one must be able to reject all such alternative hypotheses before one is warranted in making the inference. Thus one infers, from the premise that a given hypothesis would provide a “better” explanation for the evidence than would any other hypothesis, to the conclusion that the given hypothesis is true” (4). It is worth noting, however, that historical knowledge emphasizes probability as opposed to mathematical certainty. One accepts a hypothesis as historical when it corresponds to the evidence in such a way that any reasonable person ought to accept it. Essentially we accept something that has sufficient evidence to make it probable. Concerning the inference to the best explanation model one begins with the evidence already available to us and then infers what would provide the best explanation of that evidence. In this way a scientist may test his proposed explanation by performing experiments whereas a historian will test his by seeing how well it explains the historical evidence. Moreover, the are several aspects that must be considered in the historian’s reconstruction of the past via the inference to the best explanation. This was succinctly put by McCullagh’s in his influential book Justifying Historical Descriptions; in it he explains the components historians use in testing a historical hypothesis (5):

1 – The hypothesis, together with other true statements, must imply further statements describing present, observable data.

2 – The hypothesis must have greater explanatory scope (that is, imply a greater variety of observable data) than rival hypotheses.

3 – The hypothesis must have greater explanatory power (that is, make the observable data more probable) than rival  hypotheses.

4 – The hypothesis must be more plausible (that is, be implied by a greater variety of accepted truths, and its negation implied by fewer accepted truths) than rival hypotheses.

5 – The hypothesis must be less ad hoc (that is, include fewer new suppositions about the past not already implied by existing knowledge) than rival hypotheses.

6 – The hypothesis must be disconfirmed by fewer accepted beliefs (that is, when conjoined with accepted truths, imply fewer false statements) than rival hypotheses.

7 – The hypothesis must so exceed its rivals in fulfilling conditions (2)–(6) that there is little chance of a rival hypothesis, after further investigation, exceeding it in meeting these conditions.

Although this appears to be a tidy framework it is also the case that historical evidence can prove to be complex. For instance, it could be the case that some reconstructions may fulfill several of these proposed conditions but yet be deficient in others. In this way applying the inference to the best explanation can prove tricky. Alternatively, however, a hypothesis may have strength in its scope since it is able to explain a large number of relevant facts. If such a reconstruction outmatches other competing explanations given this model then McCullagh proposes that it is likely to be true. The historian should, however, accept the hypothesis that best explains all the evidence. Thus, the supposed lack of direct access to the data is not a stumbling block to testing for truth in history and so gaining an accurate knowledge of the past.


1. Thomas, B. 1993. The Philosophy Behind Physics. p. 86.

2. Collingwood, R. 1956. The Idea of History. p. 246.

3. Debbins, W. “Introduction” in Essays in the Philosophy of History. p. xiv.

4. Gilbert Herman quoted by The Information Philosopher. Available.

5. McCullagh, C. 1984. Justifying Historical Descriptions. p. 19.



  1. Important stuff to remember, James! I have heard Licona mention McCullagh’s work several times. When dealing with the Resurrection hypothesis, I have heard many skeptics claim that Jesus’ Resurrection is ad hoc because it unnecessarily brings God into the picture, which is a huge thing to suppose. How would you respond to this? And when we say “fewer suppositions” in the ad hoc category do we mean simply in number or in the “weight” of the supposition? Again, I have heard skeptics say that even though God is only one supposition, it is a large supposition to have, thus making it less plausible. Thanks!

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