This is what I wrote: "a joule from coal is significantly cheaper than a joule from a slave", read my comment again. In your reply you stated the same.
My point is that it was cheap coal energy that freed slaves, the economic realities of coal joules vs human joules, not high justice, economics.
My point is that it was cheap coal energy that freed slaves, the economic realities of coal joules vs human joules, not high justice, economics.
Then you are clearly demonstrating that you didn't carefully read the entirely what I wrote. The "free" labor of slavery was of little relative utility over other forms of social organization. In effect, it was just another (particularly egregious) form of social organization. All forms of human organization back then had about the same access to human joules. In all cases, the value of the human joules and coal joules was greatly increased through the addition of human capital in the form of skill and knowledge. Having the power of life and death obedience over people only goes so far. It gets you only a very crude application of those human joules. In order to get the maximum value out of your working population, you need forms of motivation beyond life and death obedience.
The key fact is that the productive capacity of human capital intelligently combined with energy far outstrips the output of poorly applied energy. The key is the human capital, not the energy. If it was just the energy, then you'd just have slaves running coal powered plants. You would not have had slaves running business as in the Roman Empire, or artisan slaves and paid specialist agricultural in the US.
High justice, as a form of human capital, enables economics.
My point is that it was cheap coal energy that freed slaves, the economic realities of coal joules vs human joules, not high justice, economics.