Inferring and Explaining

41 evidence in an argument.We need to fnd the best explanation. Te whole test depends on what is in frst place. In my considered judgment, Con- nie’s theory was the best explanation, and there- fore, her evidence is pretty good . For all the talk about intersubjectivity, I fully realize that some of you will have ranked t 3 ahead of t 0 . Tose of you who have come to that judgment would say that since there is a better explanation of the facts at the record hop, Connie’s evidence is weak . I have been asking my students to use the inference-to-the-best-explanation recipe to assess the quality of evidence presented in an argument for more than three decades. Te sin- gle most common mistake that my students make, including some of the best and most intelligent, is to forget about the purpose of the recipe and neglect to ofer an assessment of the evidence in the argu- ment . Tey ofen beautifully schematize it, come upwith some challenging rival explanations, and ofer subtle and insightful comments about how andwhy they have rank ordered as they have but then remain silent on the quality of the evidence. I am almost tempted to include a ffh step in the recipe saying something such as the following: 5. Conclude your analysis with one of the fol- lowing two sentences: “ Since the original theory proved to be the best explanation of the data in the evidence, the argument’s evidence is pretty good (strong, etc.) ” or “ Since there is a better explanation of the data in the evidence, the argument’s evidence is weak (poor, nonexis- tent, etc.) .” Step 4 requires an explicit evaluation of the evi- dence, as it was presented and schematized, in the original argument! What about Ties? Suppose you came to the conclusion that smooching Mary Jane and smooching Connie last weekend were equally plausible explana- tions of all the data you had? What happens in the recipe when the original and one of the rivals are tied for frst place? Tis is a classic half-full, half-empty kind of dilemma. You might say that since the original is tied as the best explanation , there’s some evi- dence for that conclusion. You might also say, however, that since there’s a rival explanation that’s tied as the best explanation, the evidence is not so hot. I think that whichever way we go, the message is really the same. Te original’s being tied as the best explanation allows us to see why someone would ofer the argument in its defense in the frst place and why there is some evidence that seems to support it. A rival being tied as the best explanation tells us that the evidence is far from conclusive. Ideally, in such a case, we go out and do a little more inves- tigating and see if we could discover some new data that would help break the tie. And indeed, the whole subject of new data is the topic for our next chapter. But before heading there, let’s apply the recipe to scientifc argument. The Origins of Natural Language Te following comes from an article by two prominent cognitive scientists, Stephen Pinker and Paul Bloom: All human societies have language. As far as we know they always did; language was not invented by some groups and spread to others like agriculture or the InferenCe to the Best exPlanatIon