« on: 03/09/2008 23:18:29 »
The way you ask the question gives away your position. You chose the word believe. This implies that you have no data. If you had data, you should be able to produce the evidence and others should be able to verify your results or come to the same conclusions. In this case, the answer is obvious.
Regarding the larger questions:
1. Is it possible that life exists elsewhere in the universe? I would suggest that given the enormous number of stars and planets the probability is quite high. Thus, my answer is based solely on a statistical argument.
2. Is it possible that earth has been visited (within the past few thousand years) by beings from another world? I would again, refer to the observational data (the vast distances between the stars and our current understanding of the laws of the universe). Based on this data, I would suggest that the probability is extremely low.
I would discourage anyone from using the word "believe" or similar term to express a conclusion or to put forth a scientific argument. The term is founded in philosophy and carries personal biases into the discussion. Thus, any conclusions based on "belief" are subject to scrutiny.