The article discusses how to determine if one thing causes another using regression analysis. It shows that simple regression can't prove causation without a theory or controlled experiments. But using instrumental variables and Granger causality can help test for causation under certain conditions. The study applied Granger causality to data on energy and economic growth in Sweden over 150 years. Results suggest that energy use affects economic growth, but this relationship may change over time. Energy prices impact energy use and output, but there's no strong evidence that energy use causes carbon and sulfur emissions.