### Clue: Disbelief that two articles are supported by one manuscript that happened to turn up (7)
### Answer: ATHEISM 
 ### Explanation: Definition: Disbelief
 [A, THE] (two articles in grammar) **placed above**(are supported by, in a down clue) [ I(Roman numeral for "one") + **reversal of**(… that happened to turn up) MS(abbrev. for "manuscript") ].