Last week, I reported on a September 4 decision from the District of Massachusetts in which the court emphasized that the presumption of validity applies to subject matter eligibility.  This week, another judge in the same district invalidated all asserted claims of a patent on a fever thermometer based on subject matter ineligibility.  Exergen Corp. v. Thermomedics, Inc., 13-11243-DJC (D. MA. September 15, 2015).  The case is noteworthy because, among other reasons, it makes no mention whatsoever of the presumption of validity or what burden of persuasion the defendants had with respect to their § 101 arguments.  One might imagine that the court in Exergen simply might not have been aware of the decision by another judge in the same district because it was issued only 11 days earlier.  However,  a review of the briefing indicates that Exergen had set forth detailed arguments as to why the claims must be presumed valid and that invalidity thus would need to be established by clear and convincing evidence.  See Exergen’s Brief at 10.  Defendants did not counter that argument in their reply; to the contrary they filed a notice of supplemental authority; that included another decision that again recognized that the presumption of validity applies to § 101 analysis (see page 5).  Whether future courts, in Massachusetts and elsewhere, give consideration to the presumption of validity in § 101 challenges remains a very open question.