Perhaps the biggest lie in the world is the lie of living in the present. The human brain is understood the receive the "present", process it and then instruct and output based on the input. The time it takes for the brain to process such information always makes the human mind process information in the past because what is seen is always in the past. Such is the case with what we see, the light from the sunlight takes about eight seconds to reach earth and this light then get reflected of surfaces which then get perceived by out eyes which then has to travel to the brain and then get processed and then the give the best sense of perception in terms of context. Since this isn't a biology less about how we see and how our brain process information, lets think about the connection to Theory Of Knowledge.
The thought of living in the past in present is defiantly evident in our thought process. Much of our decisions if not most of them are based on past experiences, pre-made conceptions, steadfast beliefs and past understandings. Therefore most of our present decision are based on our past and who we are essentially as a person. And if so then much of the future and who you will become as a person will also depend on your past and the the principles and morals that you held on to as a child. The idea is an interesting one and something worth pondering.
The decisions we make in the present our based on the past; with that idea in mind perhaps it is easier to understand why the people casually let it be and walked away. They didn't have a connection or a feeling of necessity to intervene or they didn't feel comfortable arguing about it but on the other hand some people hold on to unweary morals that when they see someone in trouble they oblige themselves to help. As seen in the video many of then just walked passed, understanding this was filmed in the united states, people don't generally have that connection or link to the islamic ideals but others regardless defend victims due to self obligation. Much of the present lies in the roots of the past and therefore the past is a foundation for what makes the present. There cannot for that reason be a present without a past and a future without past. Thats why just forgetting the past makes us incapable of living in the present. But sometimes remembering to much can also have a negative impact interns of feelings and emotions that can cause negative effects on that body.
A lot of the problems faced to man especially moral dilemmas are approached from past experiences or external influences. An interesting example is when there is a fight, the social trend is to pull out you phones gather around and film it and therefore when there is another fight you just choose to follow the social trend and choose to do nothing about it like everyone else. However some people can leave things as it is and take action and what kind of person you are depends on the what external influences that you been through. Essentially what man tends to do is move forward in live with the backward trend which leaves no room for irrational trust. Every person you trust has build a foundation of experience in your life. Even banks when lending loans have a look at if you can pay that loan back.
In conclusion there is no present without past and no present by itself cause your present is past.