Part 4/7:
The pivotal shift in perspective came with the emergence of the laws of thermodynamics in the 18th century. Even as inventors realized the impossibility of first-kind machines, a new focus emerged on designs that presumably contradicted the second law. These machines proposed to extract energy from a system without a gradient, which is fundamentally flawed.
One illustrative example of attempted violation of the second law is the Brownian Ratchet, which seemingly harnesses random molecular motion to produce energy. Realistically, it requires a temperature differential and, without one, fails to produce usable work, reaffirming the second law's inviolability.