That is the problem the grandparent is getting at. We don't have a widely accepted definition, and therefore we should tread lightly, without assuming that we're not even close to crossing that boundary.
Why would caution be not be demanded from a moral point of view? If morality places any value on the suffering of conscious beings, then the approach of "I don't know what will happen. Let's do this!" when conscious beings are the subject of an experiment is insane.
Sorry for the sarcasm (I'm definitely not trying to be impolite) but it was honestly my best attempt to make my point.
Would you say that you have an understanding of capitalism just by existing in a capitalist society?
Would even an economist or a stockbroker have an "understanding of capitalism"? Or do they just know how to make predictions? If they predict incorrectly, would you say that there understanding is less than they had thought?
Would you say that you have an understanding of the English language just by writing it?
Would even a linguist or a writer have an "understanding of English"? Or do they just know how to string words together based off a set of rules? If they write a bad paper/novel, would you say that there understanding is less than they thought?
If an understanding of capitalism/language is "less than they thought" is it really "understanding" necessarily?
Perhaps a dead horse has been beaten, but I think my point is clear: complex activities/systems that we do/take-part-in everyday do not imply knowledge of the fundamental elements of those activities/systems.
Our brains are highly skilled at pretending we have understanding.
> I also don't know how we can advance in neuroscience without taking some risks
I replied, because pointing out that we don't have a definition of something is unproductive in both ways: "we don't know what consciousness is? so let's drop precautions" is just as bad as "we don't know what consciousness is? so let's stop in place". It's quite understandable to me to feel that experimentation in this area are disturbing to someone who doesn't know what model of consciousness was used to ensure that nothing immoral is being done. The answers provided in the article don't really address that.
I also don't agree that consciousness is a complete mystery. We can infer criteria based on various measures of similarity, although the one criterion given in the article: "brain-wide activity that would indicate the organs could be conscious" doesn't offer any explanation as to where the criterion comes from. I take this as a failure to explain and justify that the precautions taken to eliminate the risk were enough.