reality in philosophy

A constant discussion that seemed to come up during conversation was about that poor tree outside of our classroom window. Is that tree really a tree?
Common knowledge is that physical objects do exist and are real. They exist in reality without any contemplation necessary. We may think that that is not a tree, maybe it looks like a tall bush to you. However, the object will not change regardless of our thoughts. This statement has always been "common sense" and a fact of life. However, when philosophy class started, other ideas poured in. Maybe the tree is not actually a tree, we just believe that it is a tree. One major thing I have learned over this semester is that things are not black and white. That fact was the hardest thing for me to accept. I like fact. It makes sense. To sit in a room and start thinking that maybe what I always thought was fact is not was hard to grasp. However, sitting and thinking more openly, instead of closed thought based on fact, helps philosophical thinking, along with other areas of learning.