Final answer:
Thomas Jefferson was not concerned about Shays' Rebellion because he saw it as a natural part of the struggle for liberty and believed that occasional rebellion was necessary. This perspective differed from other leaders who viewed rebellion as a threat to stability.
Step-by-step explanation:
Thomas Jefferson was not particularly concerned about Shays' Rebellion because of his belief in the importance of occasional rebellion for the cause of liberty. As stated in a letter to James Madison, Jefferson saw rebellion as a sign of the political alertness and determination of the populace to guard their liberties. He wrote, 'The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants. It is its natural manure.' Jefferson's perspective differed from the concerns of leaders like Washington and Madison, who saw rebellion as a threat to stability and order.