The intent of the above, parallel discussion of a series of concerns from four distinguishable and distinct perspectives was to detect the basis for possible interaction among them by revealing some of the ways in which they resemble each other on specific points. To be sure, it would be interesting to bring these different views together in a single grand synthesis, although it would seem that a result of this kind cannot, in fact, be obtained without doing violence to the ideas themselves. But since our aim is not agreement as such, but interchange when possible, it seems preferable not to undertake a synthesis here, but rather to initiate, albeit briefly, the work of comparing and contrasting the several perspectives — a project that only the reader can complete. This comparison can perhaps best be carried out through the choice of a central position in the evolution of the modern philosophic tradition, whose author cannot, however, reasonably be regarded as either a member or, more distantly, as a conceptual patron, of the other positions studied here.