From: Theories Are Beings With Life Cycles
-- 1 This theory is withering on the vine.
-- 2 This theory is still productive.
-- 3 This theory is past the time when it can bear fruit for us.
-- 4 The theory grew out of their earlier work.
-- 5 The theory was a natural outgrowth of their work.
-- 6 Many theories sprang up out of the fertile soil of his discoveries.
-- 7 The theory was nourished by later experimental results.