Now that we know what knowledge is necessary to us, we must describe the way and method in which we must know with this knowledge the things that are to be known. To do this, the first thing to be considered is that this inquiry must not be one stretching back to infinity: I mean to say that in order to find the best method of investigating what is true, we must not stand in need of another method to investigate this method of investigating, nor in need of a third one to investigate the second, and so on to infinity. For by such a method we can never arrive at a knowledge of what is true, nor any knowledge whatever.Benedict Spinoza - On the Correction of the Understanding – Boyle edition
For me, this Spinoza quote is about conceptual frameworks. If we have a conceptual framework to make sense of some aspect of our lives, then we can't expect to justify it via another conceptual framework, because that in turn would require yet another. We have to settle on a personal philosophy and make the best of it.
We differ of course, in our personal philosophies, but as far as I can see, the best way to deal with that is to find common ground, which often as not is common moral ground. There is no point arguing from within different conceptual frameworks.