|Portrait of Hegel|
It is possible that Karl Marx and Friedrich Engels developed the Hegelian triad through their own understanding of the philosophy of Hegel and Fichte. They have used it in their materialistic conception of history. In his 1847 work The Poverty of Philosophy, Marx makes extensive usage of the triad.
The origin of the triad can also be traced to Ancient Greece—to the Classical Philosophy of Socrates and Plato, and Aristotle. The Platonic dialogues follow a dialectical form: An argument (thesis) is followed by a counterargument (antithesis); either the counterargument cancels out the argument or it leads to the development of a final position which consists of a “synthesis” of the opposing arguments and represents an improvement in the position taken by the argument and the counterargument. Aristotle has said that rhetoric is a counterpart of dialectics.
Plato and Aristotle agree with each other on several points—but they also have some major differences. Platonism can be seen as the thesis, and Aristotelianism can seen as the antithesis. The process of developing a synthesis between Platonism and Aristotelianism began with the Hellenistic Neo-Platonists and the philosophers in Ancient Rome, and was finally accomplished by Thomas Aquinas in the 13th century.
The philosophy of Aquinas is not Aristotelian—it is a synthesis between Plato and Aristotle. Aquinas was inspired by the Platonic thought of St. Augustine, and through the works of Boethius, Pseudo-Dionysius, and Proclus, Aquinas picked up a lot of neo-Platonism. In his works, the tension between the works of Plato and Aristotle gets resolved—and a reconciliation is achieved between the two philosophers.