Photoshop is just the continuation of a reality of life, the difference I think is that the average person has more ability to affect the distortion of 'truth'. At the beginning of photography there were double exposures that 'proved' that there were ghosts haunting us, standing right behind us. Deceased family members could be added to photos or disgraced ones even subtracted from them. Before that people were legally required to attend religious services and could be arrested or fined if they didn't, making the religious leaders extremely powerful in what was considered truth. When there was no easy communication, media or other writers could write whatever they wanted and the folks could believe in strange miracle cures that had come from the mysterious east and that would cure migraine, scarlet fever, and birth defects all at the same time. There are many ways to experiment with the truth and that's always been a fact of life it's just more obvious now.