The discussion began with the appropriate question of the kinds of limits that are involved when we think about science. A suggestion offered was that since science is the pursuit of a form of knowledge, a limit on science would be a limit on things that we can know. Thus, the topic of the discussion could be rephrased to mean a discussion of the things that are fundamentally unknowable. However, the key point here was that these were unknowable only through the scientific method, i.e. empirically. A clarification was proposed as to what we really mean by science and the scientific method.
Science involves the building of models to explain phenomena occurring in nature.
These are thus, only models, which are imposed upon nature. They may not be exact equivalents of what there really is. Another aspect of the scientific method is observation. Without observation there cannot be any empirical science. It was suggested that this was another fundamental limit on science.