are walls really there?  humans view walls as boundaries.  if we are able to ignore the part of our brain that tells us boundaries prevent us from moving forward, then we should be able to overcome all "obstacles".  by concentrating enough and freeing your mind, a wall should no longer exist as a boundary, but as an alternative molecular field.

Reasoning

through the study of chemistry, it is taught that solid structures are made of energy.  energy is created by movement of particles.  therefore, a wall is just a bunch of moving particles.  in order to have movement of particles, the particles must have room or space.  since space is infinite, there should be an infinite amount of space between each particle.  humans are similar.  our body structure is made of moving particles that are separated by an infinite amount of space...is it coming together yet?  here it goes...if walls are made up of moving particles in an infinite amount of space, and so are humans, then given the right timing, the particles which make up a human body should be able to pass through the spaces of the wall.  for example, on a larger scale, the atmosphere is made of moving particles and aircrafts are made of moving particles.  when enough space is created or provided between the particles of each structure, the aircraft is able to penetrate the atmosphere in a process called flight.