Previous theories were not particularly scientific. These were that God created all the species simultaneously 6000 years ago. No evidence exists to support that idea. Another theory was that animals...
Psychoanalytical theory (developed by Freud) and Jung's analytic psychology, although they both consider unconscious mind to be the most important part of the psyche, have many differences. We can...
In a classical system, you have regressive, progressive and proportional. There are different types of taxes as well (e.g. income tax, luxury tax, property tax). Hope it helps.