Three Questions about Treatise 1.4.2

Why does Hume think that the "distinct existence" of sensible objects implies their "continu'd existence"? Does Hume have any reason for thinking that objects have an intermittent existence, other than that they lack a "distinct" existence? Why does Hume think that the inference from the "coherence" of our impressions to the continued existence of objects is "at bottom" considerably different from causal reasoning? The answers proposed are, respectively, that perceptually delimited objects would for Hume be causally dependent on being perceived; that Hume's collapse of the object/perception distinction leads him to the view that objects have as "gappy" an existence as our perceptions of them, and that cases of coherence falsify the generalizations that would need to hold for inferences from coherence to qualify as causal reasoning.