Aetion's
computer-assisted reasoning capability is founded upon the principles of
abductive inference, which uses commonsense reasoning to assemble the best
explanation for a set of data. In contrast with narrower probabilistic
approaches, the merit of an explanatory hypothesis is measured on several
criteria such as:
 | Internal consistency
|
 | Plausibility (including consistency with background knowledge)
|
 | Likelihood
|
 | Simplicity (Occam's razor may be applied)
|
 | Explanatory power
|
 | Specificity
|
 | Productive promise
|
One's willingness to accept a hypothesis H depends upon:
 | H's relative merit – how decisively it surpasses the alternatives
|
 | H's intrinsic merit – how good it is by itself
|
 | How thorough the search was for hypotheses that may compete with H
|
 | The need to reach a conclusion at this time (instead of, say, gathering further evidence)
|
 | The costs of being wrong, and the benefits of being correct
|
People understand these considerations and routinely justify
their own arguments in similar terms. The basic inferential step is:
| D is a collection of data (facts,
observations, givens) |
| H explains D (would,
if true, explain D) |
| No other hypothesis explains D as well as
H does |
|
| Therefore, H is probably correct |
A lot of the
power and efficiency of abductive inference comes from the way it leverages
corroboration and contradiction. The system accepts the essential (only
possible explanation) and clear-best hypotheses, the effect of
which will typically be to increase confidence in other hypotheses and to rule
out incompatible hypotheses. A good indicator of a hypothesis' merit is the
number of data that it explains; indeed, if there is no otherwise-unexplained
datum that a hypothesis explains, it offers no additional explanatory value.
Thus, driven by the currently-unexplained data, the abduction machine forms
the most confident conclusion first, and works outward from this island of
certainty.
The system
performs commonsense evidential reasoning to manage uncertainty and finds the
best consistent explanation for data. Not only can it automatically guess the
real situation but, critically, it can provide an easy-to-understand argument
that uses evidence to justify its interpretations and explanations. Therefore,
the user can collaborate with the system, controlling its behavior and working
with it in its inference process.
Our technology provides
means to maintain a working model of present reality: the set of mutually
consistent hypotheses that is accepted as the best explanation for the
observations. More information on the background to this approach can be found
in Abductive Inference
(1994), edited by John R. Josephson and Susan G. Josephson, ISBN
0-521-43461-0.
See how abuductive inference fits in with our other technologies here.