This claim actually accepts the narrator in the Torah as a historical description but claims that it is not a divine revelation but natural events or magic and tricks performed by Moses.
To this we must first reply that if it were a natural event which was mistakenly interpreted as a miracle, we would expect the people who contracted it to interpret it according to the common religious concepts in the ancient Near East, something which certainly does not fit what happened in Biblical history.
However, although experience shows that most of these “scientific” explanations do not stand up to criticism, if one does accept the descriptions in the Bible, one sees that this claim does not hold water in the first place.
Can one indeed say that events such as the plague of locusts were natural events even though there is no natural way to explain the transformation of the Nile into blood just in time for the appearance of Moses, the death of all the firstborn of Egypt at midnight precisely, the unique combination of the Pillar of Fire and the parting of the Red Sea, the manna that the children of Israel ate for forty years, and more? Attempts to say that the parting of the Red Sea was actually an exchange of tides or that Mount Sinai was a volcanic eruption and similar arguments do not stand the test of reality, and they already sound more ridiculous than the possibility that these are real miracles (Did the Egyptians not know the tide? Wouldn’t evidence of the eruption be found? Wouldn’t it have destroyed the People of Israel standing at the foot of the mountain?).
Beyond that, if these are natural events, why have they not occurred in Egypt many times throughout history? Why did they take place at the exact time when the People of Israel needed them? Why did independent special phenomena like the plague of blood, the death of the firstborn, and Haman occur so close to each other? A close examination of Biblical and Jewish history will show that this is not a temporary and local phenomenon; “special” cases have occurred in virtually all Jewish history in general (such as the survival of the Jewish people) and Biblical history in particular. Nevertheless, it should be understood that these failures are independent in the fact that hitherto the explanatory attempts given to the phenomena of the Exodus from Egypt have generally proved to be unsuccessful.
The possibility that these are Moses's tricks does not make sense either. Even modern technology cannot do such things, and how could Moses, who spent most of his life as a shepherd in Midian, do them? And if it is claimed that this is a spell, then the great Khartoum of the Egyptians were not able to confront Moses with their magic, which shows that this is a completely different kind of power.
It is possible to doubt the actual occurrence of the Torah stories, but if one accepts them as a historical description (as one is asked to do), the only logical interpretation is that these are indeed supernatural events, not natural phenomena or tricks of Moses.