>>7500
Well, yes, we do value human life. But let's pose a hypothetical question.
Let's say we shared the planet with, say…Ithorians, or Twi'leks. That would change our dynamic, because we would be dealing with non-human creatures of equal intelligence to ourselves.
As it stands, you have human life, animal life, and plant/vegetable life, in descending orders of reasoning. Humans have the greatest capacity for intellectual reasoning on this planet, and we have no equals in that regard on Earth. So naturally, our systems of thought tend to be human-centric. Now, we do have schools of thought that say, as the most intelligent form of life on the planet, and those with the greatest capacity for reason, we have an obligation to less-intelligent or capable creatures.
But my point is, can we really be human-centric if we have no out-and-out equals?