This was exactly my point of argument in-between the philosophical posts in this thread: Why are we narrowing the basis of consioucness and intelligence to humans only?
You mentioned "higher" animals, and you cut off the legal category to fish. At what point is the category going to be lowered? When we've included everything that is organic? Or down to a point that humanity will not starve or malnourish itself?
And again, you mentioned how we as humans perceive "higher" animals to be and how the world's age-old act of eat-or-be-eaten-to-survive deems as "crueltly" to a species. Is it cruelty because we as humans feel pain and sorrow to watch the species be butchered? Is it because we know how they would feel?
What is the basis of cruetly? Is it the infliction of pain? What is pain? Isn't it the information sent through the nervous system to the brain and its interpretation?
If that so, then crustaceans and insects would feel pain, too, especially when their primary system is one huge nervous system. Does that mean that they qualify as animals that should be given the same degree of consideration for cruelty?
Finally, the primary weakness of the argument of consciousness starts with the fact that it is limited to how we as humans understand consciousness. Anything else that is not like a human being cannot be defined as being conscious. Anything that does not behave or think like humans cannot have intelligence even in its lowest form.
Is there a school of thought wherein the concept of consciousness, intelligence and sentience are not limited by the parameters of a human being? (And please don't tell me that it would be Engineering. )
It is interesting to identify the reasons that we infer consciousness or the lack of it.
Firstly, we all know that one person is conscious (ourselves).
Almost everyone infers that other people are conscious, as we are similar to them, and they act in a roughly similar way to us. (There is a philosophic school called solipsism that eccentrically refuses to make this inference).
Most people infer that at least higher animals have some consciousness. This consensus has increased greatly over time, to the point where Western countries consider cruelty to fish a crime. [as a recent circus act in Australia and a kid who thought of something amusing to do with a microwave have found out]. Apparently lobsters are not yet considered conscious in law.
So it seems most of the animal kingdom is widely considered to be conscious, based on animals having some structural similarity to us, having senses and reacting to stimuli.
The only condition a sophisticated robot fails is the structural similarity to us - they are made of silicon, motors etc. rather than neurons, muscles etc.
It is a fact that if machines resemble animals, people do react to what happens to them a little like for animals, and it not difficult to believe attitudes would change to them if they behaved more like living creatures in general.