A number of question marks surround the credibility of the Atlantis story. Archaeological evidence is coming to light that corroborates much of what is hypothesised here. What about the story itself? It's no secret influential people will use rhetoric to exploit fearful ignorance. Let's first look at the person from whom the story was brought to Greece, Solon (640-558 BC).
It is possible Solon concocted his story, but unlikely. Even so, there is reason to believe he embellished it significantly. Perhaps he didn't embellish so much as change the emphasis. He was a statesman and lawmaker who fought the moral decline in Athenian society. Although largely unsuccessful during his time in office, Solon is considered by many to have laid the foundations of democracy. There is understandably no documented record of Atlantis before Solon - ignoring possible ambiguous references from Homer and Hesiod - not in Greek literature anyway.
Around 594 BC Solon was chosen as archon (chief magistrate) in Athens. Solon set about implementing reforms that were unpopular with the ruling class. He travelled abroad for 10 years so influential Athenians couldn't induce him to repeal any of his laws. There is no dispute he went to Egypt and it was there the story of Atlantis came to light. Solon visited the Pharaoh, Amasis II (reign c.570-526 BC), and spent some time with two Egyptian priests discussing philosophy. The priest Sonchis of Sais c.594 BC is attributed as being the primary source of the history of Atlantis.
Note: Sais is stated as the birthplace of the Pharaoh Amassis II which adds a little weight to Solon being there, although Sonchis being the priest who related the story is contested by some. Dates provide the most corroborative evidence.
The Greek Dark Ages (c.1100-800 BC) blotted out ancient history, as told by the Egyptian priest in the Timaeus Dialogue (Plato's account doesn't name either priest). Sonchis speaks of a great victory* by Athens in defeating the all-conquering Atlanteans. Although the dialogue is consistent, there are question marks against certain aspects. It is conceivable Solon twisted the story to put Athens in a better light, so he could best relate the moralistic tale without further antagonising those in power. On the other hand Sonchis might well have done that himself for the sake of his guest, but if he had been discussing philosophy with Solon it is unlikely.
*The 'great victory' likely refers to events of 1450 BC which sparked the decline of the Minoan / Dorian culture in the Aegean and saw the Mycenaeans / Ionians come to the fore
Whatever embellishment the story might have received at the hands of Solon, it is very likely it was further edited by Plato in order to make it more palatable to those in power. Socrates had died for his views and Plato wouldn't want to share the same fate as his tutor. Plato had a habit of 'he said, she said' to allow denial of accountability. In effect Socrates has very little bearing here as none of his works are extant and we rely almost exclusively on Plato to be his 'mouthpiece'. Just how much was from the tutelage by Socrates, and how much was purely Plato's own thoughts, is open to question.
There is no record of Timaeus anywhere else. He was Italian according to the Dialogue and his story of the creation has similarities with the biblical version in Genesis. Critias is genuine, as is Hermocrates the third speaker - who never spoke, or whose dialogue is lost. Both are referenced by others from the time. Nor is the existence of Socrates in doubt. What is in doubt is if these dialogues were the result of a coming together. The chronology makes such a gathering very unlikely, though not impossible.
It is almost certain the part of Socrates in the dialogues are assumptions by Plato, on how he perceived his mentor would respond. Nevertheless, although most date the Dialogues to 360 BC, some 39 years after the death of Socrates, it is not an indication such a meeting never took place. Perhaps Critias told the story quite simply to Plato one on one, as it had been handed down to him. Plato then invented the concept of a gathering to give more credibility.
Of those gathered, Hermocrates c. 5th century – 407 BC, was an ancient Syracusan general. Timaeus c.5th-century BC was suggested to be a Pythagorean philosopher from Italy but was most likely an invention of Plato. Critias was the son of Callaeschrus and a first cousin of Plato's mother Perictione. He became a leading and violent member of the Thirty Tyrants. Such a gathering carried far more weight than the lone word of an executed philosopher.
Socrates had a strange role in the Dialogues. From what Critias states, it infers Socrates was constructing a moral tale. This strongly suggests a conspiracy of sorts but it makes far more sense Solon and / or Plato were the perpetrators rather than Socrates himself. Plato was tutored by Socrates yet he had to hear the story from Critias, which means Socrates hadn't made the tale public knowledge.
This doesn't discredit the tale, it merely advises caution when assessing truthful elements. Plato may well have met Critias at some time and heard Solon's story. By combining the account of Critias and the assumed thought machinations of Socrates, he in effect told the story his tutor hadn't. The more we look at it, the more we see evidence of some kind of fabrication. Was Plato responsible for carrying out a deception or merely recording the thoughts of others? Was Socrates even at the gathering?
In Critias the Gods are barely mentioned apart from Poseidon, Though purported descendants of the Gods, the mortality of the Atlanteans (Aegearans) is clear. At the end of the incomplete Dialogue there is mention of Zeus as 'God of Gods' before the text stops abruptly. Did Plato see he was painting himself into a corner? Perhaps it was for dramatic effect, the story ending as abruptly as Atlantis and the last mention being of Zeus.
To conclude, irrespective of possible conspiracy theories and the ideology behind them, influenced by Solon / Socrates / Plato, the main body of evidence is indicative the basis of the Atlantis story IS historical fact.