Synergism is not Pelagianism. Confusing the two is a very common mistake, particularly in Calvinist/Reformed circles where any system that involves human cooperation is sometimes loosely labeled “Pelagian” or “Semi-Pelagian”.
However, historically and dogmatically, they represent fundamentally different views on grace and human nature.
Pelagianism was condemned as a heresy precisely because it denied the absolute necessity of divine grace. What Pelagianism actually taught: Named after the 5th-century monk Pelagius, Pelagianism claimed: No Original Sin: Adam’s sin only hurt Adam. Humans are born morally neutral, in the same state Adam was before the Fall. It falsely claims that there is no need for internal Grace: Humans possess the innate, natural moral ability to keep God’s commandments and achieve salvation entirely on their own. We already know that is biblically incorrect.
Pelagius argued that “grace” merely meant God giving us free will, the Law, and Jesus’ good example to follow. Because Pelagianism taught that man can save himself through his own natural willpower without God’s internal transformation, it was condemned at the Council of Carthage (418) and the Council of Ephesus (431).
Then you have Semi-Pelagianism. A later variation, Semi-Pelagianism, acknowledged that humans are corrupted by sin and need divine grace. However, it argued: Man must take the first step toward God on his own (initium fidei). Once man reaches out to God, God steps in with grace to complete the process. Semi-Pelagianism was also condemned as heresy at the Second Council of Orange (529) because it taught that the initial desire for God originates in man rather than God. Again, we know this to be false. John 6:44, John 12:32, etc.
How Synergism differs, and why it is not Pelagian: Orthodox Synergism (held by Eastern Orthodoxy, Roman Catholicism, Methodism/Arminianism, and Anglicanism) rejects both Pelagianism and Semi-Pelagianism: Pelagianism says: “Man doesn’t need grace; he can choose God by his own strength.”
Semi-Pelagianism says: “Man must choose God first, and then God supplies the grace.”
Synergism says: “Man is completely helpless until God’s grace reaches out first. That grace frees man’s will so he can either accept or reject God.”
Therefore, holding to Synergism does not make someone a Pelagian. Synergism asserts that salvation is 100% initiated by God’s grace, but requires a real, unforced human response enabled by that very grace.
Be blessed, be a blessing.
Peter