The day before this article appeared, I participated to a talk about consciousness, and the presented dismissed the functional approaches to explaining consciousness. That is, if consciousness processes information, it is not a information processor LIKE the computer is. You can not define a thing by what it does, but only what it is. The electron is not something that moves through space, but something that has mass, charge, and so on. That is, you define it by its intrinsic properties. Otherwise, you could say consciousness is what made possible this comment here. That'd tell you absolutely nothing.
But there was a biologist that basically said what you're saying: what is then 'walking', don't you define it by a 'is doing'? And this objection misses the mark because 'walking' is an action, not an entity. On the other hand, the brain, presumed to be responsible for consciousness is not (not equal to) 'talking', 'walking', 'imagination', 'recognition'. These are faculties, but not the underling physical/ontological support that make these faculties possible.
The whole project of explaining consciousness must reveal the underlying substance, be it matter or something else, that make it possible, and the mechanism by which all faculties associated with consciousness arise.
And one more thing: the main conundrum of explaining consciousness is 'qualia', that which is experienced by being conscious, that which is it like to be conscious.