Because the behavior of things on a very tiny scale is simply different.

I don't prefer one to the other; they are simply different.

The inner mind is simply different in its essential configuration.

Their life experiences are simply different from those of the younger women.

The geometry of space is simply different for spin one half particles.

Norman states that in this "natural order" men and women are neither superior or inferior, simply different.

They were simply different from those practiced in London drawing rooms.

The selection process was simply different from what we thought.

He had studied humans, and concluded that they were simply different.

You are both simply different pulses of the same vibrations.