The ontological paradox is essentially when an object or person is sent back in time, and creates itself, making an endless loop with no discernible origin. This is also known as the bootstraps paradox, because the thing is "pulling itself up" by its own bootstraps.
Although this is very similar to the predestination paradox, the ontological paradox is separate from it because it involves an object or person which is creating this infinite loop. In the predestination paradox, it is an event which creates the loop.
An example of this is in the terminator movies. John Conner sends Kyle Reese back in time to protect his mom from the terminator, right? But, Kyle Reese ends up getting with John Conner's mum, creating John Conner. So, if Conner had never sent Reese back in time, Conner would not even exist to send Reese back in time. This is the sort of infinite feedback loop to which the bootstrap or ontological paradox refers.
Although this is very similar to the predestination paradox, the ontological paradox is separate from it because it involves an object or person which is creating this infinite loop. In the predestination paradox, it is an event which creates the loop.
An example of this is in the terminator movies. John Conner sends Kyle Reese back in time to protect his mom from the terminator, right? But, Kyle Reese ends up getting with John Conner's mum, creating John Conner. So, if Conner had never sent Reese back in time, Conner would not even exist to send Reese back in time. This is the sort of infinite feedback loop to which the bootstrap or ontological paradox refers.