In the logical context of Thorndike's laws of multiple trial and partial action in 'Trial and Error Theory', what is the analytical difference in the nature of Stimulus-Response (S-R) and Response-Stimulus (R-S) between Pavlov's 'Classical Conditioning' and Skinner's 'Operant Conditioning' that most clearly distinguishes the learning process of these three theories?

Thorndike's learning theory is based on the 'Law of Effect' and 'Trial and Error' where satisfying consequences strengthen the connection. According to the Wikipedia reference provided by Ivan Pavlov, classical conditioning is based on the S-R (Stimulus-Response) paradigm in which an artificial stimulus is presented before the natural stimulus (conditioned response). In contrast, B. F. Skinner's 'Operant Conditioning' is based on the R-S paradigm, where the organism first makes an operant response and the subsequent reinforcement determines the frequency of that behavior.