Are Semantic Web Services the next step?

(Originally published at TheBlog on January 20, 2006)

(This is a reply to the article Is it time for SOA developers to start thinking about semantics?).

I have some experience with SOA and web services, and also have looked a little into the world of semantic web services. And to summarize my position: I am very much skeptic about the latter.

SOA is a new wave of traditional computing that works or, at least, is clearly viable. "Traditional" means that it relies in humans programming machines mainly using procedural approaches like Java or activity/flow diagrams. Non-IT, Domain users are increasingly able to do so.

Semantic Web Services (SWS) is the new incarnation of symbolic Artificial Intelligence agents. They have been there since several decades ago. Each time a new computing wave appears, the symbolic AI people come in saying "hey this is good but it would be superb if you put semantics on top of it". The high level approach is always the same: use declarative programming not to tell the computer how to do something, but what it has to do.

The underlying technology is irrelevant to this; it is just the same whether they are using dumb terminals, client-server, web applications, or a SOA. It is so irrelevant that the SWS world is a bold new one. You have to start learning tons of things about ontologies, description logics, planning and many other things that, while may be useful in many respects, are usually very far away from the actual, day to day needs of real Domain users of computers. And, you know, resources, experience and tools about it are far, far less aboundant and with far less quality than with standard computing. And once you spent months learning v(or trying to learn) it, then you try to apply it to the real computing, and you find that the world happens to be much more complex than theoricists think it is. (In particular, you find that declarative programming is in general more complex than procedural one, to which does not help the much worse tools and support).

For until now, the result of these semantic attemps is always the same: much promises, and very little deliverance. In the meanwhile, the rest of the computer industry goes on doing useful things and creating new waves, and the symbolic AI people remain entrenched in their ivory tower, attending to events and figthing themselves. For, did I talked about a single world of semantic web services? Sorry! Telling people behind OWL-S (mainly from US) that they are just the same as people behind WSMO (mainly europeans) I think is an outrage to them. If you attend a presentation of one of them, they will tell you that "the other approach" is just flawed and is in the process of fading away. Last time I attended one, I asked the speaker about the unifying initiative of SWSI and he did not know about it. And OWL-S and WSMO are not even the only initiatives, existing several minor other ones.

I am fully convinced about that, some day, computers will be really able of intelligent thinking. But I am also quite convinced that this will not come from the hands of symbolic AI, but from less clear machines in the track of neural networks (i.e. non-symbolic AI). But until then, what has worked and what I think will continue working, is mostly traditional, procedural computing.

However, I grant that the current initatives behind the Semantic Web have a new flavor, with much more people behind it than in other incarnations. Maybe this, along with the superior power of todays computers and the availability of the WWW will make a difference. But from what I have seen, I remain skeptical.