So society is no more than an elaborate lie built on self-deception on a massive scale?

I certainly think we self deceive, that motivations are hard to discern and that much is still a mystery to science.

Many would disagree and argue that rational, nonviolent self-interest actually holds societies together through facilitation of commerce and mutually-beneficial human interactions. Is an Hobbesian war of all against all in anyone's self-interest? Surely not.

Empathy and utilitarianism are philosophically quite well intertwined (the British Empiricist philosophical tradition combined both utilitarianism with moral sentimentalism (i.e. empathy), see Adam Smith's The Theory of Moral Sentiments for more. It is empathy that changes the utilitarian analysis into one of natural human benevolence due to the fact that people prefer more utility to less, and the utility of others is part of our own utility.

Ah we can analyse society and say people are acting on rational self interest and agree with Adam Smith.

This is unconscious though right? Non optimal. People seem to do irrational things. They do non self interested acts.

The idea that if we became "hyper rational" self motivated beings that society would flourish seems doubtful. I think a society based rigorous analysis to optimise self goals would probably collapse. Likewise it would collapse if it was all communitarian.

I think Smiths society relies on the communitarian elements of self sacrifice which I would argue have biological roots.

I also have a problem with the notion of rationality here as if "Reason" was a moral goal.

Adam Smith's friend Hume is remembered for his quote "Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them." I think that hits the nail. That's the key point.

Many philosophers would argue that moral truths can be discovered by reason.

We use reason to understand our passions. Reason is never a motivation.

Not only that, but the simple fact is that people often have very different emotional responses to the same phenomena - this would undermine the argument that moral truths can be discovered through emotions.

I would agree moral truth is a very difficult topic. I see no universal agreement.

Reason has not found an answer to this.

You cannot get an "ought" from an "is."

Are you saying that there can be no rational motivations or rational goals?

Yes.

Ultimately emotions are the motivations. Logic does not want anything. Logic is tool in the service of desire.