I want to know the answer to the following question:
What was later realized that caused naturalistic mechanisms such as neo-Lamarckism to be embraced?
All the background I'm provided with is that "In America, Asa Gray argued that evolution is the secondary effect, or modus operandi, of the first cause, design, and published a pamphlet defending the book in terms of theistic evolution, Natural Selection is not inconsistent with Natural Theology.". Is that enough to answer the question?
Answer: no