Law of complexity/consciousness is the idea that the more complex something is, the more conscious it will become. To explain this, let's look at it like this: When you go to a store, you usually have something in mind that you want to buy. This is because you have become aware of the items that are in the store, and you have thought about what it is you want to buy. This awareness of the items in the store and the thought of what you want to buy is consciousness.
The more items a store has, the more complex it is. The more complex the store is, the more choices you have and the more aware you become of all the different items. This increases your consciousness and allows you to make a better decision on what to buy.
So, the law of complexity/consciousness states that the more complexity something has, the higher the level of consciousness it will have.