lol gotta love the "science"-y threads here, pages of large wall of texts on politics, few lines on poop and gas on 'science'
Speaking for myself only here, I can put togeather walls of text on Scifi, or politics, no probs, but actual *hard science* I cannot speak with any true authority, or even inkling, and quite frankly I generally would prefer not to BS on something I know nothing about. (Physics/metaphysics excepted, mainly due to the metaphysics part)
Should we do it?
For "ancient species" I would argue no simply due to the fact that we will have no real knowledge of what the re-introduction of species this old will have on not only us, but our world. Examining genetic coding, well sure, that could work if such a thing is possible without reconstituting said lifeform.
More modern extinctions, ones more caused by us............
Difficult. Technically, I would say Yes, we should because it is because of us they are extinct, but as was noted before, do we still have the environment to support them anymore?
Then you have the observation Rac noted, does the fact that we CAN do a thing, mean we SHOULD do a thing?