4 ms·

That essay isn't very convincing. All of his examples of logical failures would only work with the most poorly defined ontology and the most brain dead reasone

by woodman 11y ago

That essay isn't very convincing. All of his examples of logical failures would only work with the most poorly defined ontology and the most brain dead reasoner, which is probably why he described everything using the term "syllogism". For example: US citizens are people The First Amendment covers the rights of US citizens Nike is protected by the First Amendment He then goes on to say that one would conclude that Nike, being a person, has kidneys according to some medical database. First, the ontology: why would you join a medical ontology on "person", instead of something more rational like "human" (you know you're going to have medical data for animals as well)? Second, logical failure: the second statement is not one of exclusivity, you cannot actually link the third statement to the prior two. I'm sure this guy is very clever, and has plenty of great qualities - but he has built his argument around the failure of logic, when it is clear that he doesn't know very much about it. The use of very poorly defined terms makes it look like he is aware of this...

Retric 11y ago
You can't assume automated systems will behave "reasonably". F=m*a is a great rule most of the time that happens to stop working at various edge cases. Sadly, you can say the same of all of physics and just about every other rule. Even things as 'simple' as living vs dead can get really complicated with lots of odd edge cases. http://en.m.wikipedia.org/wiki/HeLa http://en.m.wikipedia.org/wiki/HeLa new species?
- woodman 11y ago
  > You can't assume automated systems will behave "reasonably". Well, automated systems constructed by people - as ontology construction and semantic reasoner writing is primarily a human activity (... yeah I see it). It would be pretty funny if we end up with a semantic web, where logic is king, having ontologies mapped by a probabilistic AI though. As far as edge cases are concerned, that is why you use an open world assumption [0], allowing the reasoner to return "Unknown". Which would act as a compiler error for human understating. Of course that won't save you from reclassifications, but nothing will. I haven't done much thinking on the matter, but I can't think of anything that would better handle the expansion of a knowledge graph than an OWA semantic reasoner. I've done a bit of work with neural networks, and changes in the domain are not well handled by neural networks. I imagine the results of a large graph change would create in the neural network something that would look very human - confirmation bias :) [0] http://en.wikipedia.org/wiki/Open-world_assumption http://en.wikipedia.org/wiki/Open-world_assumption
  - haddr 11y ago
    I would say that OWA is an interesting feature, but still far from being perfect. In the real world cases, we need sometimes to perform some sort of validation, where we need true/false answer rather than Unknown. This is where OWA falls short. For instance in the case of cardinality problem. (For those who doesn't know: In OWL you can say that a person can have only 1 father, but then you might add 2 fathers for one person, and the reasoner would be perfectly fine with that. It assumes that both persons might be actually the same instance)
    - woodman 11y ago
      > ...where we need true/false answer rather than Unknown. If you've set things up with that sort of constraint, then you've set yourself up for failure - Gödel's incompleteness theorems [0]. I think OWA is the only way around that, you just need to gracefully handle unknowns. Of course, you can convert an unknown into a known pretty easily with: ¬u :) > For instance in the case of cardinality problem. That is exactly when I'd want my reasoner to ignore a graph edge, or else you get a non sequitur that ends with Nike belonging in the human set. Measure twice, cut once. [0] http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_t...
haddr 11y ago
Spot on. That given example neither convinces me. The second sentence is actually false/incomplete and would mislead not only a reasoner, but a human too. The problem with author's thesis is that he want's semantic web to universally describe the whole world. This is impossible because the world is changing and sometimes contradictory. OWL for instance doesn't cover such assumptions, and in general most knowledge representation frameworks are monotonic, so it's impossible for instance to withdraw some fact by adding a new one. That what might be a real limitation of the Semantic Web as we know it.
- nickbauman 11y ago
  The second sentence is something being debated as a result of the Citizen's United ruling, so his essay seems oddly prescient. > the world is changing and sometimes contradictory If you think ontologies don't change and will not require constant maintenance I have a bridge to sell you.
  - deleted 11y ago
    [deleted]
  - icebraining 11y ago
    Not particularly prescient; the issue didn't appear with Citizen's United. Back then, there was already a law proposal (the McCain-Feingold bill) to limit spending by corporations and other groups on political ads. http://en.wikipedia.org/wiki/McConnell_v._FEC http://en.wikipedia.org/wiki/McConnell_v._FEC
    - nickbauman 11y ago
      McCain-Feingold is about limiting corporations behaving like citizens. Citizens United is the expansion thereby making the conclusion much more logical today than when it was first written in 2003.
      - icebraining 11y ago
        Yes, but I linked to McConnell v. FEC, which was a challenge to McCain-Feingold much like Citizens United v. FEC. The issue was already on the table, the decision just happen to go the other way.

by woodman 11y ago

Retric 11y ago

You can't assume automated systems will behave "reasonably". F=m*a is a great rule most of the time that happens to stop working at various edge cases. Sadly, you can say the same of all of physics and just about every other rule. Even things as 'simple' as living vs dead can get really complicated with lots of odd edge cases. http://en.m.wikipedia.org/wiki/HeLa http://en.m.wikipedia.org/wiki/HeLa new species?

woodman 11y ago
> You can't assume automated systems will behave "reasonably". Well, automated systems constructed by people - as ontology construction and semantic reasoner writing is primarily a human activity (... yeah I see it). It would be pretty funny if we end up with a semantic web, where logic is king, having ontologies mapped by a probabilistic AI though. As far as edge cases are concerned, that is why you use an open world assumption [0], allowing the reasoner to return "Unknown". Which would act as a compiler error for human understating. Of course that won't save you from reclassifications, but nothing will. I haven't done much thinking on the matter, but I can't think of anything that would better handle the expansion of a knowledge graph than an OWA semantic reasoner. I've done a bit of work with neural networks, and changes in the domain are not well handled by neural networks. I imagine the results of a large graph change would create in the neural network something that would look very human - confirmation bias :) [0] http://en.wikipedia.org/wiki/Open-world_assumption http://en.wikipedia.org/wiki/Open-world_assumption
- haddr 11y ago
  I would say that OWA is an interesting feature, but still far from being perfect. In the real world cases, we need sometimes to perform some sort of validation, where we need true/false answer rather than Unknown. This is where OWA falls short. For instance in the case of cardinality problem. (For those who doesn't know: In OWL you can say that a person can have only 1 father, but then you might add 2 fathers for one person, and the reasoner would be perfectly fine with that. It assumes that both persons might be actually the same instance)
  - woodman 11y ago
    > ...where we need true/false answer rather than Unknown. If you've set things up with that sort of constraint, then you've set yourself up for failure - Gödel's incompleteness theorems [0]. I think OWA is the only way around that, you just need to gracefully handle unknowns. Of course, you can convert an unknown into a known pretty easily with: ¬u :) > For instance in the case of cardinality problem. That is exactly when I'd want my reasoner to ignore a graph edge, or else you get a non sequitur that ends with Nike belonging in the human set. Measure twice, cut once. [0] http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_t...

haddr 11y ago

Spot on. That given example neither convinces me. The second sentence is actually false/incomplete and would mislead not only a reasoner, but a human too. The problem with author's thesis is that he want's semantic web to universally describe the whole world. This is impossible because the world is changing and sometimes contradictory. OWL for instance doesn't cover such assumptions, and in general most knowledge representation frameworks are monotonic, so it's impossible for instance to withdraw some fact by adding a new one. That what might be a real limitation of the Semantic Web as we know it.

nickbauman 11y ago
The second sentence is something being debated as a result of the Citizen's United ruling, so his essay seems oddly prescient. > the world is changing and sometimes contradictory If you think ontologies don't change and will not require constant maintenance I have a bridge to sell you.
- deleted 11y ago
  [deleted]
- icebraining 11y ago
  Not particularly prescient; the issue didn't appear with Citizen's United. Back then, there was already a law proposal (the McCain-Feingold bill) to limit spending by corporations and other groups on political ads. http://en.wikipedia.org/wiki/McConnell_v._FEC http://en.wikipedia.org/wiki/McConnell_v._FEC
  - nickbauman 11y ago
    McCain-Feingold is about limiting corporations behaving like citizens. Citizens United is the expansion thereby making the conclusion much more logical today than when it was first written in 2003.
    - icebraining 11y ago
      Yes, but I linked to McConnell v. FEC, which was a challenge to McCain-Feingold much like Citizens United v. FEC. The issue was already on the table, the decision just happen to go the other way.