We cannot qualitatively distinguish between ontologies, except through the other qualities we were already examining.

If that is supposed to mean that every ontology comes with its own isolated, tailor-made criteria, and that there are no others ... then I dont think the situation is quite that bad: it;'s partly true, but there are also criteria that span ontologies, like parsimony.

We don't have a way of searching for new ontologies.

The point is that we don't have a mechanical, algorithmic way of searching for new ontologies. (It's a very lesswronging piece of thinking to suppose that means there is no way at all). Clearly , we come up with new ontologies from time to time. In the absence of an algorithm for constructing ontologies, doing so is more of a createive process, and in the absence of algorithmic criteria for evaluating them, doing so is more like an aesthetic process.

My overall points are that

1) Philosophy is genuinely difficult..its failure to churn out results rapidly isn't due to a boneheaded refusal to adopt some one-size-fits all algorithm such as Bayes...

2) ... because there is currently no algorithm that covers everything you would want to do.

So it looks like all we have done is go from best possible explanation to best available explanation where some superior explanation occupies a space of almost-zero in our probability distribution.

it's a one word difference, but it's very significant difference in terms of implications. For instance, we can;t quantify how far the best available explanation is from the best possible explanation. That can mean that the use of probablistic reasoning does't go far enough.