Is Consciuosness an Illusion?

This is not an origial idea of mine, see for example The Grand Illusion:
Why consciousness only exists when you look for it. Suppose it is an illusion, then what is it?

I beleive consciousness is simply an analytical function in the brain. You can't say that something has it or not. Rather, that something has more or less of it. Most things we do today are done unconsciously. This means that we will find the right response quickly, almost without realizing that it was done. This is because the response has been learned by the brain. When we encounter something that is new to us, then something interesting happens. Because of the fantasic human intellect, we frequently are able to work out a new response. The first time, it will take some time. But with practise, it will soon be learned and can be handled unconsciously. This gives humans a very strong competitive edge compared to other species.

A common example is from some sports. To be really good at the sport you are practicing, you have to learn it by heart. If you play table tennis and don't have the right reflex, you will fail immediately. More training is needed.

Using this (vague) definition of consciousness, now let's see if animals, plants, or computer programs could be considered to be conscious. Most animals will act immediately on reflex. When I throw a ball to my cat, it doesn't stop to think and compute where the ball will be. Instead, it will dash ahead, and usually catch the ball. The reason that it succeeds is that it is very quick, not that it realizes where the ball will bounce. Sometimes the cat will lie down and look at what I am doing for a long time, but I have never seen it's behavous change because of it. I just think that the cat depends more on instincts and reflexes than on conscious analysis. Because of that, I believe the cat is much less conscious than human beings, but not zero.

A plant doesn't seem to have any analytical power. It is entirely pre-programmed, and by my definition, completely unconscious. Well, it wouldn't surpise me if there are plants that are somehow able to learn and react through some chemical system, which would give it a consciousness greater than zero (but only just).

A computer program certainly takes a lot of time sometimes to find answers, but in general does not change it's behaviour. It is however hard to say something for sure about all computer programs. For example, there are fairly advanced AI functions that control monsters in computer games. These monsters will react and behave differently depending on what the player do. While fairly complex, I would still consider this as similar to pre-programmed instincts. I have not seen a game where the monsters come back the next day and adapt to your way of playing. I do expect this to happen any time soon, as it should certainly be technically possible. It is a thing that is interesting to the computer game industry as players usually become tired of playing only against AI driven monsters. The usual solution to this is to allow players to play against other human players, which will behave different every time. To summarize, I would say that computer programs aren't conscius, but there will soon be programs that will behave more and more consciously.