No ET! Ever?

[Aoi Magi]

Chemicals might behave differently under different different conditions but they do so by following the rules of nature and this are predictable. And since the rest of the universe seemingly follows the same natural laws, so predictable assumptions can be made safely about it.

Having said that, many scientists agree that we probably won't recognize an Alien lifeform at first glance given the wide variety of life on Earth itself. But on the other hand, since we know there are many planets similar to ours and that the base constituents oh the organic molecule thought to have caused life on Earth is freely available in the universe, it is safe to assume lifeform similar to ours can be found on places with similar conditions.