I believe if everyone in the developed world were to follow Will's argument and adapt their life to give everything they possibly could then the world would face economic collapse, historic levels of unemployment, technological stagnation, and ultimately, a significantly less happy world now and for future generations to come.

As a starting point, let's consider the very end of the podcast where Sam is talking about going out to lunch. He paid $25 for lunch, but he didn't need to do this. He could have eaten at home for a few dollars and then sent the extra money to someone in true need. How can he justify this?

Sam Harris is a consequentialist, and a thoughtful one at that. So considering the full array of consequences is in his purview, and it should be in ours too. Let's stay on merely the restaurant industry, and ask ourselves what would happen if everyone in the developed world decided to never eat out again?

I think it would be fair to say that the entire restaurant industry would go under. Even if implicit in Will's argument is the ability to occassionally go out to eat, the restaurant industry would still die out. Restaurants have very thin profit margins. To even have their profits cut by 10% would be devestating to all but the healthiest of business owners. And it seems clear that following Will down this path would result in a world where people don't go out enough to support even a single restaurant.

Everyone in the restaurant industry would now be out of a job. But it's even worse than that. Anyone who might have made money designing a new menu or a new restaurant website, or creating a new ad (etc) would feel the sting as well.

Follow this line of thinking across every industry. How many stay afloat? Very few. Does Apple produce anything people truly need? What about Sony, or Samsung or Intel? Not really. And if we live in a world where people aren't buying things we don't need, most tech companies are out of business.

At this point a proponent of Effective Altruism (or someone merely playing devils advocate) might say "Well even if the developed world faces huge problems as a result, it's necessary to overcome the suffering in the third world. Bringing them up to a better living standard will help all of humanity."

But I think this is yet another case of not fully thinking through all of the consequences. Economic collapse also entails technological collapse. The reason the world has so much computing power right now is due to the fact that we live in a world where everyone wants more computing power (and doesn't really need it.) Nobody needs a laptop or a smartphone. And even if you make an argument that we really do need these things, we don't need them in the same way a starving person needs food, or the way a village needs access to clean drinking water.

In a world where everyone who has any money has given it all away, how would we fund something like artificial intelligence research? We wouldn't. Society wouldn't have the backbone for ancillary things like AI.

Again, a proponent of Effective Altruism might come in and say "well so what? A world where everyone is brought up to a better standard of living but less technology is still preferable."

And here is the crux of the issue. I dont' believe that it is. Technology presents humanity with the very best chance of creating a happy world for everyone. And not just a happy world for the 7 billion inhabitants of the planet right now, but for the 500 trillion people that represent the future of humanity.

If technology ever leads us to something like a utopia, even if it doesn't happen for a long time, then the happiness that hundreds of trillions of people will experience in the future outweighs by several orders of magnitutude what a mere 7 billion people experience in the present.

And this is the main consequence that I feel like Will failed to encapsulate in his thinking. Economies drive technological change, and technological change drives everything else. And in a world where the first world has given everything to the third world, we're left with a stagnant "second world" where there is no economic or technological advancement because all of humanity is barely above subsistence.

tldr: Effective Altruism -> Economic Collapse -> Technological Collapse -> Average living conditions where no one can improve. (aka, global communism)

Edit: And to head off the counter "Well not everyone will do it, and so the world will continue on as it is." It is hardly the mark of a good moral system that in order for it to succeed we have to make sure most people don't follow it.