The First Industrial Revolution used water and steam power to mechanize production. The Second used electric power to create mass production. The Third used electronics and information technology to automate production. Now a Fourth Industrial Revolution is building on the Third, the digital revolution that has been occurring since the middle of the last century. It is characterized by a fusion of technologies that is blurring the lines between the physical, digital, and biological spheres.
This definition is taken from the world economic forum
I believe that the definition of the fourth industrial revolution is wrong. We will look back and see that while having a connected world delivers significant advances, it will be the advance of artificial intelligence that will really drive transformation over the next two decades.
After all cyber-physical systems will only realise their potential if they are supported by the intelligence that advances in data science and machine learning will be able to provide.
From my perspective the connected world is just the final phase of the third industrial revolution. The quantum leap, the fourth revolution, will be delivered by artificial general intelligence (AGI) and super intelligence.
Only time will tell how history will view and categorise the advances in these technologies over the coming decades. What we do know is its the most interesting time to be involved in the technology field, especially artificial intelligence.