"Unlike a logical inference made by deduction where one proposition can be logically inferred from other known propositions, and unlike induction where a generalized conclusion can be inferred from a range of known particulars, inference to the best explanation—or `abductive inferences'—are drawn about a particular proposition or event by a process of eliminating all other possible conclusions to arrive at the most likely one, the one that best explains the available data." Bitler v. A.O. Smith Corp., 391 F.3d 1114, 1124 n. 5 (10th Cir.2004).
At times, the court's error in excluding Dr. Smith's testimony derived from a mistake in its understanding of the weight of the evidence methodology employed by Dr. Smith. The court treated the separate evidentiary components of Dr. Smith's analysis atomistically, as though his ultimate opinion was independently supported by each. For example, the court referred to "Dr. Smith's opinion that because benzene metabolites inhibit topo II and because some classes of topo II inhibitors appear to have a causal relationship to APL, therefore benzene has a causal relationship to APL." Milward, 664 F.Supp.2d at 148 (emphasis added). This overstates Dr. Smith's conclusion as to the topo II evidence, and is indicative of an error in the court's understanding of the nature of Dr. Smith's analysis.
In Dr. Smith's weight of the evidence approach, no body of evidence was itself treated as justifying an inference of causation. Rather, each body of evidence was treated as grounds for the subsidiary conclusion that it would, if combined with other evidence, support a causal inference. The district court erred in reasoning that because no one line of evidence supported a reliable inference of causation, an inference of causation based on the totality of the evidence was unreliable. Cf. Nutra-Sweet Co. v. X-L Eng'g Co., 227 F.3d 776, 789 (7th Cir.2000) (holding that an expert's reliance on individual pieces of evidence, insufficient in themselves to prove a point, "did not render his opinion speculative"). The hallmark of the weight of the evidence approach is reasoning to the best explanation for all of the available evidence. Cf. Dalkon Shield, 156 F.3d at 253 (reversing district court's exclusion of expert testimony as "guesswork" or without "basis" when testimony was based on differential diagnosis and there was no showing that any one of the expert's premises was "so faulty that it could not even be tendered to the jury for its consideration"); see also Hardyman v. Norfolk & W. Ry. Co., 243 F.3d 255, 261 (6th Cir.2001).
The dynamic evidence page
Evidence marshaling software MarshalPlan
It's here: the law of evidence on Spindle Law. See also this post and this post.