Anything that is this emotionally and mentally challenging will have nay-sayers.
I welcome nay-sayers with a warm embrace. I believe nay-sayers are singularly responsible for all progress mankind makes - there is always someone who will take up the challenge of proving them wrong! :)
Among things they point out, here are three frequent ones:
1. God made humans, therefore machines will never be as intelligent.
"As intelligent" will certainly be proven untrue.
There is an interesting nuance in this assertion: The type of intelligent.
I am not claiming that machines will be human-like intelligent (based on my research I believe that being human-like bring big limitations).
Consider this though: If you want task x done, and the machine can do that task more efficiently and effectively than a human... Does it really matter what kind of intelligent it is?
Such a superintelligence is some ways away, but it will be able to complete tasks like running transportation systems, growing crops, telling you want you need before you need it, writing better stories, and even truly falling in love.
The type of intelligence used to get there will be different than our (human) intelligence - and far, far superior on a multitude of dimensions.
2. Are you on crack? There is not enough data for machines to get smart!
Two things.
First, you are right that in order for certain types of learning to occur we will need a lot more data. A billion trillion new sensors deployed strategically to collect all the data about weather. A billion of tiny nano-sensors floating in our bodies and minds will collect medical and psychological data about us - down to an atomic level. All the data in every transportation system - not just all the engine and speed data - but sensors embedded in the skin-structure of the vehicle will collect stress and other data. None of these three examples I shared exist today. But, do you honestly think that in 2019 these are not solvable problems? All three are currently being worked on. Your brain activity is just electrical impulses.
Second, the beauty of AlphaZero is that it does not need classified data. It just needs the rules. Life is not as simple as Chess - nor that structured. But, starting small and growing big this is simply a matter of focus. We don't know the rules for true love. I believe we will get there when the incentives are so big.
3. The human brain is a gazillion trillion computations at super low power and superintelligence will require chazimilion mamilian dapromilion amount of xyz.
True.
But consider the power in a single Tensor Processing Unit (perhaps the world's most powerful single purpose computing device). Then consider that between May 2016 and May 2018 the processors are a multitude times faster with a multitude more chips giving incredible performance boosts. This will continue at that scale for a while.
Then, there's the fast approaching Quantum Supremacy - the ability of quantum computing devices to solve problems classical computing practically cannot. An unimaginable explosion of computational power - and the that problems we think that power can solve.
Jürgen Schmidhuber predicts it will take 20 - 25 years to have a recurrent neural network comparable with the human brain. It is not that far away.