Well, I cannot describe exactly what a system must be configured to say that it is conscious, but I can certainly draw a line on having a cognitive system (that is, a system for perceiving, elaborating and storing information).

A thermostat has these properties. So does a coin or rock too, if you look at it from the perspective of having vibrational modes, electric potentials & eddy currents, stored potential and spatial configuration with respect to, say, a gravitational field. It's a bit more of a stretch than a thermostat (as we tend to mentally abstract away the coin or rock as something with no internal structure), but I hope you can see the argument.

Saying “necessary but not sufficient” is an escape technique. “A system for perceiving, elaborating and storing information” could be stretched to cover every interaction of two or more particles. So these properties are unrelated to the issue and there is some other, specific point at which you wish to draw the line and say “all things which have this property are conscious, those which do not are not.” What is that point?

If you don't know what that cutoff is then consider, at least hypothetically, the possibility that there is no dividing line. Then there is a continuum of conscious experience from the ϵ-consciousness of two interacting particles to the jumbled mess of interactions that is our brain (spanning orders of magnitude in difference that maybe only astronomers are used to dealing with).

If you conflate consciousness with informational complexity, then you can do away with the term and just call it complexity. It doesn't make consciousness any less mysterious, it just sweeps the problem of what differentiate a human from a coin under the rug.

I'm not, and you've misunderstood my point. I think Goertzel and I are on the same page that consciousness is an algorithm in motion. Even thermostats, coins, and rocks run algorithms (yes even rocks, where the steady-state quantum interactions of its composite particles do form an algorithm governing response to, say, vibrational events). So, even a rock or coin has epsilon consciousness.

This is my position which I think Goertzel shares. It's at least in line with what he said in the documentary about coins having minute, but non-zero consciousness.