[ 6/6/20 ]
There aren’t any.
What does exist is individuals who run into paradox in some specific context.
What that indicates is that the interpretive schema in use is not sufficient to model the complexity actually present that they are interested in, and that a new paradigm is required.
Once you have encountered that a dozen or so times, and have had to change schema to resolve and remove the paradox, you start to gain an appreciation for the complexity and uncertainty that seems to actually exist in reality (beyond any shadow of reasonable doubt); and start to appreciate that all models and understandings are likely to be simplifications of what is actually present, and thus necessarily wrong in some essential aspects; and thus one adopts the processes of the scientific method to become progressively less wrong.
If you think about it deeply, whatever exists is real. Paradox can only exist when the model in use is not able to match what is being considered.
What most people don’t deeply consider is that all experience is already a simplified model of reality, simplified by the subconscious physical and processing systems of brain and sensory systems. So we don’t ever experience reality, what we experience is a kind of personal virtual reality statistically assembled from uncertain information using Bayesian priors deeply sorted and selected by evolution at both genetic and cultural levels. Without those biases we would not be able to make any sense at all of the complexity within which we exist.
So paradox is not a characteristic that belongs to reality, it is an indication of a failure of the modeling systems in use. All it means is that it is time to upgrade the modeling system to be able to handle the new level of complexity that you actually encountered.