Thank you Medici. I am happy to respond and point you to some additional resources. There is a wonderful book by Melanie Mitchell called “Complexity — A Guided Tour” if you are interested in exploring it further.

1. Complexity and Equilibrium cannot co-exist. Equilibrium is the ultimate state of “death”, whereas Complexity is the ultimate state of “vitality”.
2. Complexity is hard to define even for experts in the field. There are many ways to think about it, but none capture the quantitative and qualitative aspects completely — complexity can be defined in terms of information content, entropy, logical depth, computation, algorithmic ways (defined by Kolmogorov etc.). But all of them aim to capture the new/novel/emergent dynamics arising out of simple substrate/materials interacting in ways that are impossible to capture with physics alone.
3. Yes, that’s a good point — and for example, assuming the human brain is a physical substance (network of neurons, synapses) following well defined physical laws underlying them, how can we explain the emergence of consciousness, intelligence, emotions, vocabulary, ideation, creativity etc.? That’s complexity for you.
4. Heat death is not a blob — it’s a state of highest entropy and information content, but lowest state of complexity. Imagine the static on the old TV (CRT) screens — you can’t make out the pictures because there is none..once the picture appears, it’s definite contours etc. are reminiscent of complexity. The “static” is a state of lowest complexity and highest disorder, and highest information content.