My thinking was that the college educated applicant has had the course content fed to them whilst the other person has presumably acquired the knowledge more organically.

The non-college acquisition is likely to be part of a wider more connected level of knowledge too as that knowledge - that matches the college acquired knowledge - is a snapshot, the college educated person is more likely to be limited by the boundaries of the course material.

In order to acquire such knowledge in the field the non-college applicant is likely to have needed just the same interpersonal skills and a whole heap of drive and enthusiasm for their subject matter. On top of that they, presumably, have proven ability in their field if someone has been paying them a living whilst they've been applying this knowledge.

>Given two candidates of equal knowledge, one with no degree and one with a degree in art history, I would hire the art history guy with little hesitation. //

Art History is awesome; a single term of that at undergrad level enriched my life considerably. That aside the guy with art history and (presumably) programming knowledge is likely to have a useful diversity of approach.

I think I'd have a greater expectation that the subset {k} of the candidates domain knowledge implies a larger superset {K} for the non-college candidate.

[disclosure: I'm uni educated and don't work as a programmer]