John Duns Scotus was born in the town of Duns around 1266.
A series of events kicks off with a talk in its Volunteer Hall on Saturday followed by a walk on Sunday and an library exhibition opening on Monday.
Dr Philip Tonner, head of philosophy at Hutchesons' Grammar School, said Duns Scotus remained a significant figure.
He said he was considered by some to be a precursor of other major philosophers such as Rene Descartes and Immanuel Kant.
The festival hopes to bring the importance of his works to a new audience.
"One of the problems, of course, is that medieval philosophy became seen to be something associated with very esoteric problems about how many angels can dance on the head of a pin and so on," said Dr Tonner.
"This is a very unfair depiction of what medieval philosophers were trying to do.
"It is one of those unfortunate accidents of history that it has become associated with Duns Scotus who in many ways is certainly one of Scotland's most important philosophers and one who is still making headlines in both theology and philosophy."
A festival is under way in the Borders to mark the 750th anniversary of the birth of one of Scotland's most important philosophers.