On Sun, Apr 16, 2017 at 6:34 PM, Alex <[email protected]> wrote:
> Well, the mentioned book has chapter about inheritance, but it is in no > way connected with the terms of intensional and extensional inheritance. > So, this book is not usable. > Sure, its usable. Opencog inheritance is still inheritance. The difference between extensional and intensional is this: you can define a set by listing all the members of the set, for example, "fluffy is a dog" "fido is a dog" "satan is a dog", etc. this is the extensional definition of a set: it describes the extent. The intensional definition is this: "dogs are all those things that have fur, four legs and bark". one lists all the properties that the members of the set must posess, the "intensity" That's all. > > Now I am looking Non-Axiomatic Logic: A Model Of Intelligent Reasoning by > P. Wang and it should be fairly good book, because OpenCog uses term > logic and the idea about possible use of term logic (more than 2000 years > after Aristotle) in present times comes from P. Wang (as described in PLN > book), but I have no access to this book, so..... > There's a PDF of the PLN book online somewhere. Someone can send this to you. > > It could be nice to know where such notions about extensional and > intensional inheritance comes from. > Aristotle, I believe. Seriously, the idea is thousands of years old. Thomas Aquinas. The Scholastics. > OpenCog wiki says that intensional inheritance (class inheritance) can be > understood as subset relationship but from my programming experience I can > say that this is wrong perception. Subset relationship is subset > relationship but class is something more: class has class functions, class > as a concept exists even without members of this class, class has factory > methods/constructors/destuctors - means of creating new instances and so > on. Class (in some lanuages) can have multiple inheritance. So, I am still > afraid of adopting OpenCog notions. > class has many meanings besides the one used in programing/c++. Opencog uses the more general meaning. Even C++ originally used the word "class" in the general sense; only later were the notions of type theory formalized. The problem is that class membership, in type theory, is binary; the standard example is the functor from the opposite category into class set, -- what is called the "pre-sheaf". That's the high-falutin way of undrstandin it. There's more, lots more, in this area. I'm guessing that you don't really know javascript very well, or have never taken any formal courses in lisp or scheme. Read the first 3-5 chapters of SICP it will expand your mind a lot. > > To be honest, I am a bit afraid to include in my thesis project that uses > term logic - it is just fragment of monadic predicate logic and it was > decided some 150 years ago that more extensive logics (full predicate > logic) are necessary for more expressivity... > Huh? What's term logic got to do with this discussion? > -- > You received this message because you are subscribed to the Google Groups > "opencog" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/opencog. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/opencog/d5114d44-aff0-42d5-b53e-d0d01870b628%40googlegroups.com > <https://groups.google.com/d/msgid/opencog/d5114d44-aff0-42d5-b53e-d0d01870b628%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "opencog" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/opencog. To view this discussion on the web visit https://groups.google.com/d/msgid/opencog/CAHrUA352H2M_2zKbLBMMg7U6a1P3y45npAqoi8jQ-L8Rf0sDnw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
