Plato combines and transforms the teachings of his philosophic predecessors. He agrees

with the Sophists that knowledge of appearances is impossible;
with Socrates that general knowledge is conceptual;
with Heraclitus that the world of appearances is always in constant change;
with the Eleatics that the world of ideas is unchangeable;
with the Atomists that being is plural (ideas);
with Anaxagoras that mind and matter are distinct.