DEFAULT-LOGIC ANALYSIS: ILLUSTRATION OF PLAUSIBLE REASONING #3
"MODUS TOLLENS" REASONING
Professor Vern R. Walker
Hofstra University School of Law
Hempstead, New York, 11549 USA
Text for Illustration of Plausible Reasoning #3 ("Modus Tollens"):
Howard v. Secretary of Health and Human Services,
2006 U.S. Claims LEXIS 95 (March 22, 2006) (Office of Special Masters)
[Decision at p. *6] "On April 10, 2000, Sierra received her third hepatitis B vaccination, along with a varicella vaccination ("com vax") and a hemophilus influenza B ("HIB") vaccination. (Ex. 4, p. 4. 4) Thereafter, she was not taken to see her pediatrician, Dr. Bianchi, or any other physician, until May 26, 2000. (Ex. 4, pp. 38-39.)"
[Decision at p. *26:] "... as Dr. Berger emphasized, during Sierra's first year of life, her mother seems to have taken Sierra to see Dr. Bianchi fairly often, even for relatively mild illnesses. (Tr. 82-83; see also Ex. 4, pp. 40-50.) This makes petitioner's current testimony seem even more unlikely. That is, it seems unlikely that Sierra could really have been "withdrawn" or "depressed" for six weeks, and had "puffy" hands and feet for more than three weeks, and yet petitioner did not take the infant to the doctor during that time period."
[Decision at p. *52:] "... I have concluded that the factual scenario assumed by Dr. Katz was unlikely--that is, that Sierra probably did not experience the symptoms, during the April 10 to May 23 time period, now described by her mother. Therefore, the first symptoms of Sierra's HIS likely did not occur during the time period soon after vaccination that Dr. Katz apparently deems appropriate."
Clues and Cues for Analysis