As Blobbers said.
This sounds like a religious belief so not something I have any way of understanding.
I've written many algorithms that solve "complex problems" and, in fact, its by working in AI that I know that you can model a lot of animal behavior without appeal to anything akin to sentience. Ants, I think, are absolutely fascinating.....but I don't think for a minute they are sentient. The complex behavior we seen in ants is emergent behavior from the interactions of thousands/millions of mindless units following a simple and rigid rule set (e.g., "when smell X is detected, do Y", etc).
You seemed to start this thread with the claim that fish are indeed sentient....that is a lot stronger than saying that there is a lot we don't know so I'm going to give them the benefit of the doubt. I'm not bothered by people giving fish the "benefit of the doubt" as there is a lot we don't know, but I think such arguments get a bit absurd when they are applied to animals that lack brains entirely. But since the case of fish is a lot less clear than the case for mammals, I don't think people should spend that much time on fish advocacy. For me the main issue with fish is environmental, farming them involves the same environmental issues as farming other animals and sustainable wild caught fish can be at best consumed very occasionally.
Scientists have all sorts of individual beliefs, their individual beliefs aren't legitimized by being scientists. What matters is the actual evidence and I don't think there is much evidence to point to fish sentience. Do fish react to negative stimuli? Of course...but do they experience suffering? I think that is doubtful.
So when you take them out of water and they are gasping for oxygen, what is that? Just a reaction? They're not suffering?
There is no maybe about it, you can create a robotic ant, but what makes ants so special isn't individual ants but how they interaction. Eusocial ants are, in a sense, a superorganism.
It does seem that way, but that is what makes them emergent properties. The complex interactions of simple rules can result in complex behavior that is near impossible, computationally, to predict from knowing the rules. One interesting way of seeing this graphically its Conway's game of life:
I'm not sure what you're trying to say here but I never suggested that people shouldn't express their views and I haven't personalized any of the issues.
Breathing, in all animals, is largely unconscious so yes its a reaction. But perhaps you mean the flipping around many fish do when taken out of water but there is no reason why such behavior would require sentience as its a very simple behavior. Of course humans tend to interpret such behavior as suffering but that is because when humans, or mammals, act in such ways they are usually suffering. One has to be careful not to misinterpret the reasons for other animals behaviors, the further they are removed from us evolutionary the less likely the behavior has a common cause.
I think that is a perfectly reasonable position in cases, like most fish, where there are still a number of details we don't know but I don't think it makes that much sense to extend to all animals. Or, I should say, its not clear why one would err on the side of caution when it comes to animals that lack central nervous systems but not plant, fungus, etc In both cases there is no known mechanism by which the entities could suffer.
I've written a lot of different types of algorithms but professionally mostly dealing with reasoning, that is, getting computers to solve logical problems (both mathematical and otherwise).
Size, complexity and structure of the brain.
The computational capacity of the human brain is dramatically greater than an ant or even a fish so being able to simulate the behavior of an ant colony or fish doesn't mean one could simulate a human.
Well, you can tell when someone is acting, or something is real.
Because there are limits, at least currently, to the computational power of computers. But also ant and fish behavior is much simpler than human behavior and as such its easier to model.
I think I've felt pain.....but maybe I just think I have? What is the difference between thinking you've felt pain and really experiencing pain? But such questions get you deep in the Philosophy of mind.
Having the receptors for pain, and hence being sensitive to damaging stimuli, is not the same as having the ability to suffer. Nobody questions whether fish have capacity for pain, the question is whether they suffer. That is, whether they experience pain. Humans conflate the two because for us pain is always always associated with suffering.
