I’m getting quite confused by the mixing of metaphors here. It seems very odd to call something that is described as a hinge as a foundation. My impression is that W talks about hinges in the context of debates and doubts. I understand them as propositions that are protected from question and debate, at least in a given context. Perhaps its not unduly mixing metaphors to say that an actual hinge enables the door to swing and also defines the space through which it can swing.
The idea of protecting a proposition is exemplified for me by the following. We may well notice that water that is heated will often begin to boil at a certain point. We can measure that point, and when we do, we find that it does not always boil at the same temperature. We could abandon our generalization, but we don’t. We look for additional variables and end up with a more complicated, but more accurate generalization.
Two more metaphors. One of which is very useful because it allows us to think about multiple levels of certainty (the water in the bed and the bed in the landscape) But can it be applied to hinge propositions. But multiple levels of hinges doesn’t make sense.
There’s a wide range of metaphors in the text.
There’s no reason to suppose that these are interchangeable. I don’t think we are likely to be able to build a taxonomy out of this.
Should we not expect that all these metaphors will give us slightly different pictures, which might be more appropriate in some cases rather than others. Treating them as interchangeable seems very confusing.