In Part III of this book, we saw Hume claim that we may only imagine causes when we are in a "philosophical" state of mind. Yet in Part II, we saw that we must always imagine causes. Which will it be? In the Appendix to 1.4.6, we saw what looks to be a response to this question, where Hume seems to gesture towards the necessity of transcendentally conceived of objects, particularly in regard to the object, the "self." But in the three sections leading up to 1.4.6, Hume focuses on those imagined causes that come about as a result of an inevitable "philosophical" approach to the world. By taking a careful look as these sections, while bringing Hume's thoughts on abstract ideas to bear, we may examine Hume's thoughts on justified v. unjustified belief in objects in much more detail than we did in  Chap. 3.