I don't think I can say I actually understand it, but the most complex thing I have ever tried to understand is basic molecular biology. The simple processes by

I don't think I can say I actually understand it, but the most complex thing I have ever tried to understand is basic molecular biology. The simple processes by which the instructions to produce a protein from constituent molecules is encoded, transcribed, and reproduced, via other proteins that induce signal cascades and fit with each other to close and open channels that propagate the signal. I say "simple" but it's amazingly complex and a miracle that such a thing is possible and actually happened. Somehow, the electromagnetic properties of specific configurations of protons and electrons can create exactly the right shape of field as to make it possible for them to chain together in a way that encodes the ability to produce exact copies of the same configuration from available inputs and free energy, and that just happened, with no supervision or intent or purpose, and from that, a part of the universe now exists with thoughts and values and teleology and collectively attempts to bend the rest of the universe to its purpose. How? Why? There is no answer and I will soon no longer exist to ask the question, and soon after that nothing will exist that can ask questions, but the fact that, for some brief period, part of the universe became self-aware, information that will eventually be lost forever, is a miracle. And I got to be a part of it. And I got to spend a few years trying and failing to grok how basic principles of physics and chemistry can make this possible.