The understanding of the world around us requires the use of various theories representing different levels of emergent structure. While they enjoy a decoupling, they are not completely independent. It has been acknowledged that the possibility for complexity to emerge sets constraints, indeed a fine-tuning, on the fundamental constants of nature. It turns out that at each level of emergent complexity, new such constraints appear. It is not clear whether they are more stringent or obviously satisfied in view of constraints relevant for lower levels. We discuss the connection between fine-tuning of fundamental physics, atomic physics, chemistry, and biology to highlight the importance of the analysis of the connection between these different theories in relation to fine-tuning.