# Decision Theory in Ending Of Person Of Interest 2x21

On the end of the recent episode of the Person of Interest titled ‘Zero Day’ (season 2 episode 21), The Machine is about to get admin access to the person answering the pay phone, it is about to call.

Decision theory talks about one of the possible processes of decision making. The decisions are compared in a way, that every possible decision is paired with every possible environmental variables. Then the person looks at the matrix and sees, if any of the possibilities are better than the others.

The decisions we are going to examine here is Harold’s decision that lead to who is answering the pay phone at midnight. That person is going to be the one, that have the ability to control The Machine for 24 hours.

First decision: Meeting Root

The first decision, that lead to this is his decision about meeting Root. Root on one hand offered him information about The Machine and Decima Technologies, but on the other hand, his information has the risk of letting Root take control of it.

Let look at his matrix. On one hand, he is choosing between meeting Root and not meeting Root. But what he doesn’t know and can’t control at this point is, if he has enough information to stop Decima by himself.

So what are the consequences of meeting Root?

If he meet Root, and he would be able to stop decima technologies by himself, that means he is giving Root the access to the machine. If he meets Root, and he wouldn’t be able to stop decima technologies, than he is also giving access to Root.

But if he doesn’t meet Root and he is not able to stop them, that means, that Decima will be able to control the machine. But if he is able to stop them, without meeting Root, than he saves the machine.

Harold here played safe and instead of risking The Machine to fall in the hands of Decima, he goes to Root. He perceives the danger of Decima as the most unwanted scenario and takes the decision, that stops it.

Second Decision: Wiring the Phone

At the end of the episode, Harold is wiring the phone, in order to stop Decima from getting to The Machine and let Root get access. The decision about Root getting access is already made, as stated in upper example.

But with the arrival of John and Shaw another dilemma presents itself. Only Root or also John? The thing he can’t control at that moment is how The Machine is going to respond. It can give access to only Root, only John and both of them.

If Root is the only one with the access to The Machine, than in any situation, the Root is the one controlling it. And she will set it free, as she stated before.

If beside Root, John also gets access to it, than there are three different ways it could go.

1. Only Root gets access. At that case, The Machine is set free.

2. Only John gets access. Root gets violent and The Machine is safe.

3. Both Root and John ger access. The Machine is going to start making decisions on case to case bases. It will be unpredictable, but it can go both ways.

As we can see, if John also gets that call to it, than in worst case scenario, the situation is the same as if he does not get it. But it can also become better, potential saving The Machine as Harold intended it to.

That is why rerouting the signal to the pay phone next to John was made.