Well - what if you make a new fiddle out of old wood? 
I see at least 2 different "beliefs" discussed in this thread:
1. that old fiddles age over long periods of decades/centuries; and
2. that new fiddles somehow "break in" over the first months/year of being played.
The first would be tougher to test, but I would at least expect there to be scientific papers explaining the specific changes that take place, and how that would affect the acoustics. WRT the second, if there are studies comparing the acoustics of 2 new fiddles, where 1 is played for a year and the other sits in its case, I have not seen them.
I'm not expert enough to say neither 1 nor 2 happen, nor have I exhaustively researched the literature. But if someone holds the "belief" that either 1 or 2 occur, I would expect them to be able to point to something other than vague suggestions of how materials change over time, their perception that something occurred, or having heard a story that appeals to them.
Of course, I've never been big on religion, either...
I see at least 2 different "beliefs" discussed in this thread:
1. that old fiddles age over long periods of decades/centuries; and
2. that new fiddles somehow "break in" over the first months/year of being played.
The first would be tougher to test, but I would at least expect there to be scientific papers explaining the specific changes that take place, and how that would affect the acoustics. WRT the second, if there are studies comparing the acoustics of 2 new fiddles, where 1 is played for a year and the other sits in its case, I have not seen them.
I'm not expert enough to say neither 1 nor 2 happen, nor have I exhaustively researched the literature. But if someone holds the "belief" that either 1 or 2 occur, I would expect them to be able to point to something other than vague suggestions of how materials change over time, their perception that something occurred, or having heard a story that appeals to them.
Of course, I've never been big on religion, either...