When Plato was discussing the Republic and Aristotle was laying the foundations of logic, the map of the East was very different from what one might imagine today. The term "Turkey" did not exist, and certainly, neither did the Turks themselves. The land that is now known as Turkey was, back then, a mixture of Phrygian plains, Lydian rivers, Greek colonies, Persian satrapies, and the ancient remnants of the Hittite civilization.
In Ionia, on the coast of Asia Minor, people spoke Greek. It was here that Thales, Anaximander, and Heraclitus were born, and it was here that the first scientific ideas were forged—long before Plato even came into the picture. Cities like Ephesus, Miletus, and Smyrna were never "Turkish." They were either Greek or Persian, depending on the era, but they always looked towards Greece, not the East.
Further inland, in the plains of Central Anatolia, lived ancient peoples like the Phrygians and the Lydians. King Croesus, who believed he was the happiest man alive during his reign, ruled in Lydia, in what is now part of Turkey. But was he Greek? No. Was he Turkish? Not even close. The Turks at that time were far away, somewhere deep in Siberia or Mongolia, with no connection to the Aegean shores.
The regions of Anatolia were under the control of the Persian Empire during the time of Plato and Aristotle. The Persians had conquered these cities and governed them through local satraps. Their influence was strong, but even under Persian rule, the Greek cities of Asia Minor retained their language, culture, theaters, philosophers, and freedom of thought.
Even further back, before the Persians, there were civilizations with remarkable archaeology. The Hittites, who spoke a mysterious language and had their own kingdoms, dominated the same regions a thousand years before Aristotle. But again, they were not Turks, nor did they have any connection to Islam, which would only emerge nearly a thousand years later.
So, the answer to the question of what existed in Turkey when Greece had Plato and Aristotle is: a world without Turks. A world with Greek colonies, Phrygian kingdoms, Persian rule, and a rich historical layer from civilizations that have long since vanished. What existed then has almost no connection to the modern Turkish state.