Intelligence, knowledge will not occur without an observer. Try to visualise a system of events without an outside observer. There will be no meaning in such a system if each element of the system were to analyse it's own experience and come to conclusions about the environment as a whole.Even if each element advertise it's own experience, you will need other elements to do the advertising - like photons, the problem is these advertising elements are also part of the system and there should exist a method to analyze the actions of these advertisers. On the other side, each element needs to know the whole universe which don't look very practical.
A better method is to have outside observers independent of the system to observe the happening of the elements.
This system will have elements which will be basic building blocks where action will be performed. Then there will be massage carriers that are independent of elements. Then there will be observers.
You can draw a parallel with a drama or a play. There will be actors who perform, then there is a medium that carry the message to the ordinance, and there is an ordinance that enjoys the play. The actors being human, cannot be barred from also being ordinance, but, ideally they should not.
The actors, ordinance and medium need to be independent. But like in a play they may be fused together. For instance message carriers - usually photons, are also elements, but the don't have a dual responsibility. When they carry massages the will cease to be elements. Most of the problems arise in a system when responsibilities are fused together. A good example is light signals in special relativity. They are the messenger but they are also elements.
Observer will have a memory that will record the events the elements played out. Then it will have the ability to identify symmetries in these records and compress the data. This will help it to use this compressed data to find out further symmetries and make more compressions. This compression and its symmetries are the knowledge. These compressions and symmetries are embedded in our brains are called knowledge. The more the person is able to find symmetries, the more knowledge he will have.
Memory alone in the brain will not constitute knowledge, when it is able to find symmetries of the memory and compress the data, finding more links in the data, it's knowledge will increase.
There is another twist in the observer. The scientific knowledge or universal knowledge happens when all the observers merge into one universal observer. This will give universal facts that everyone accepts.
Observer gives meaning to the system. Without him the system is just a random set of events. Observer will find the patterns and the meaning of the system.
Observer can poke the system to obtain desired effects. This is seen in a play when the audience claps.
Observer may poke a system to get a response. There will be no difference between elements themselves doing something or observer poking the system. The difference will be observer can use the knowledge that he poked the system. This is casualty.
There are two kinds of observers, passive and active. Astronomy observers are passive they are unable to participate in astronomical events like birth of a supernova. An observer working in a lab say an particle accelerator will be actively poking on the elements being experimented.
The passive observer cannot guarantee casualty of events.
Active observer can state an event was caused by him. He will have empirical evidence that if he did not act the event will not take place.
We cannot ignore the observer and interpret the happening of events. Special relativity is a case where the influence of the observer is embedded in the theory itself that try to interpret events of moving frames.
The passive observer experiences while active observer experiments.