On Monday 28 July 2008 07:04:01 am YKY (Yan King Yin) wrote: > Here is an example of a problematic inference: > > 1. Mary has cybersex with many different partners > 2. Cybersex is a kind of sex > 3. Therefore, Mary has many sex partners > 4. Having many sex partners -> high chance of getting STDs > 5. Therefore, Mary has a high chance of STDs > > What's wrong with this argument? It seems that a general rule is > involved in step 4, and that rule can be "refined" with some > qualifications (ie, it does not apply to all kinds of sex). But the > question is, how can an AGI detect that an exception to a general rule > has occurred? > > Or, do we need to explicitly state the exceptions to every rule? > > Thanks for any comments! > YKY
There's nothing wrong with the "logical" argument. What's wrong is that you are presuming a purely declarative logic approach can work...which it can in extremely simple situations, where you can specify all necessary facts. My belief about this is that the proper solution is to have a model of the world, and how interactions happen in it separate from the logical statements. The logical statements are then seen as focusing techniques. Thus here one would need to model a whole bunch of different features of the world. Cybersex is one of them, sex is another. The statement "Cybersex is a kind of sex" would be seen as making a logical correspondence between two very different models. As such one would expect only a very loose mapping, unless one were specifically instructed otherwise. This puts the conclusion at 3 on very shaky ground. Consequently the conclusion at 5 must also be considered unreliable. (It could still be true.) What logicians call logic doesn't bear much resemblance to what people do in their day-to-day lives, and for good reason. A logician looking at it would argue with almost every step of the argument that you have presented, as it's quite ill-formed. (E.g., what does "a kind of" mean?) A biologist would probably deny that cybersex was sex. So would a pathologist. So this could be seen as an example of "From a false premise one can draw any conclusion". N.B.: You called this a fuzzy logic problem, but you don't seem to have specified sufficient details for such logic to operate. Specifically which details are missing varies slightly depending on exactly which version of fuzzy logic you are considering, but they all require more information than is present. Still, I don't think that's the basic problem. The basic problem is that your "rules" require a large amount of unstated knowledge to make any sense...and this is pointed up most clearly by the statement "Cybersex is a kind of sex". To properly model that statement would require an immense amount of knowledge. Much, but not all, of it is built into humans via bodily experience. An AI cannot be expected to have this substratum of intrinsic knowledge, so it would need to be supplied explicitly. ------------------------------------------- agi Archives: https://www.listbox.com/member/archive/303/=now RSS Feed: https://www.listbox.com/member/archive/rss/303/ Modify Your Subscription: https://www.listbox.com/member/?member_id=8660244&id_secret=108809214-a0d121 Powered by Listbox: http://www.listbox.com
