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recognized a process as within the statutory definition when it either was tied to a 
particular apparatus or operated to change materials to a 'different state or thing.'"  437 
U.S. at 589 n.9.  Finally, the Court in Diehr once again applied the machine-or-
transformation test in its most recent decision regarding the patentability of processes 
under § 101.  450 U.S. at 184. 
 
We recognize, however, that the Court was initially equivocal in first putting 
forward this test in Benson.  As the Applicants and several amici point out, the Court 
there stated: 
It is argued that a process patent must either be tied to a particular 
machine or apparatus or must operate to change articles or materials to a 
'different state or thing.'  We do not hold that no process patent could ever 
qualify if it did not meet the requirements of our prior precedents. 
 
Benson, 409 U.S. at 71.  In Flook, the Court took note that this statement had been 
made in Benson but merely stated:  "As in Benson, we assume that a valid process 
patent may issue even if it does not meet [the machine-or-transformation test]."  437 
U.S. at 589 n.9 (emphasis added).  And this caveat was not repeated in Diehr when the 
Court reaffirmed the machine-or-transformation test.  See Diehr, 450 U.S. at 184 
(quoting Benson, 409 U.S. at 70) (“Transformation and reduction of an article ‘to a 
different state or thing’ is the clue to the patentability of a process claim that does not 
include particular machines.”).  Therefore, we believe our reliance on the Supreme 
Court's machine-or-transformation test as the applicable test for § 101 analyses of 
process claims is sound. 
 
Nevertheless, we agree that future developments in technology and the sciences 
may present difficult challenges to the machine-or-transformation test, just as the 
widespread use of computers and the advent of the Internet has begun to challenge it in 
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