This is a timeless question in philosophy. How can we be sure that the world exists?
Our perception of the world is different from what it is.
Science has shown that the world is made up of point energy sources, separated by 99.9%+ blank space. Some of these point sources can be organized into 3D structures, while others are organized into biological cells and molecules. Our body is made up of trillions upon trillions of cells, including our brain with its billions of electrical impulses that are generated every second.
What is the world we see? What does this have to do with what is “outthere”? Is it real? If so, how can we know why?
Our brain creates a model of our world. This model includes surfaces, solid objects and people. It also includes familiar faces, food, water, and food. These concepts represent the environment in relation to our survival as humans: objects that we can grab, surfaces we can walk on and objects that we can grab. People who can help us as well as food and water can sustain us. This model includes our body as well as our concept of who we are and what it means to be an individual.
This is how the world appears to our eyes:
Although the model we create is not “real”, it is informed by the external world.  Brain’s sensory and motor systems keep the internal model in line with the environment. Because 1) It is all that we have and 2) it behaves consistently like it is real, we experience what we see as real.
The only way to make what we perceive real (and in some absolute sense) and that it is possible for us to interact with it and test our beliefs regarding the environment.
A hologram is a way to show your love.
The apple image looks real. It could very well be real. However, when we attempt to interact with it (e.g., trying to grab it), we discover that there is nothing. Our ability to communicate with the world reliably is what makes us believe it. Although we can’t know the future, our brains tend to believe that beliefs are true. However, we find out later that they’re not. It’s like trying to reach the end of a rainbow, but never getting there.
How do we see images in our mind?
What is the difference between the conscious and the unconscious parts?
Is perception reality?
Where are “we” in reality?
Does consciousness mean that we are not conscious?
 Philipona D., O’Regan JK. Nadal JP. Is there something else? Sensorimotor interactions can be used to infer space. Neural Computation. (– Google Scholar)
 O’Regan JK, Noe A (2001). An account of vision and visual consciousness from the sensorimotor perspective. The Behavioral and Brain Sciences. (http://scholar.google.com/scholar?cluster=13022515942196894869