Viruses are not considered to be living unless they are present in other organisms.
We cannot see bacteria or anything microscopic because they are too small........
Can we explain this by this logic....
We see things only when they are hit by the light rays which then reach our eyes.....but bacteria are too small compared to light rays that light rays cannot hit them and hence they couldn't be seen.....
But wait, I have another question, if the above logic is correct then bacteria would even not be able to see each other...because bacteria are not getting hit by any light ray so they couldn't be seen even by others...