Choosing to trust
Previously we explored the challenges of trust on the Semantic Web and described our take on how we might go about engineering a trust layer for the Semantic Web technology stack. This post elaborates on the challenge of making a judgement of trust. Recalling the two questions posed in the previous post:
- Can I rely on this piece of information?
- Can I trust this service provider?
As we observed previously, both questions call for a judgement to be made based on available information.
Consider the first question, of whether to rely on — and therefore trust in — a piece of information. We believe this decision should be based on the level of belief that is held in that statement. Furthermore, our level of belief in a statement should be grounded in an assessment of its credibility and plausibility.
To clarify further, we consider the credibility of a statement to be an assessment of the reliability and trustworthiness of the agents and processes involved in its assertion. Such an assessment would likely include analysis of the provenance data associated with the statement, as well as a review of reputation information and first-hand experiences of the actors and processes involved.
With respect to plausibility, we consider it to be a measure of how likely a statement is to be true, against the background of our existing knowledge, taking into account confirmatory or contradictory knowledge and trends.
The second question has much in common with the first; while the primary concern of the judgement is over the expected behaviour of the service provider, it too must be concerned to some degree with the provenance of information.
Reputation information is valuable in judging expected behaviour and facilitates interactions with yet un-encountered providers, however the provenance of reputation information is also important because disreputable sources may provide fraudulent information when collaborating with disreputable service providers.
Therefore, if we are to construct an ecosystem of Semantic Web technologies in order to engineer trust as a macro phenomena, we must first engineer robust provenance and reputation systems for the Semantic Web.
