Kanizsa's Triangle

Kanizsa's Triangle is an optic illusion discovered by Gaetano Kanizsa in 1955. You can notice a white equilateral triangle, but there isn't any one. This effect is known like "subjective outline". What's more, the white triangle seems to shine more than the surrounding area, but it has the same brightness than the bottom. 

This is one of a lot of optic illusion to prove that "reality" is something different of what it seems to be. When we observe something (an apparent objective fact) our brain's operation mechanism, our experience and our knowledge give to this fact an interpretation, a particular meaning. 

Thus, if it happens with a figure, what will happens with social facts, in which people has particular choices and behaviours? it is posible to be objective?

For me, it's so important to stop and thinking about all the point of view that we can imagine before take a decision in front of any fact, because sometimes our brain is tricking us. And this is a simple and visual way to explain it, trough a geometric figure.