There are a lot of things that we don't understand about intelligence, too many to make any absolute statements about our limitations. DNA in itself, even though we have mapped out the "genetic code", is still a very large mystery to us.
http://www.foxnews.com/science/2013/12/13/secret-second-code-found-hiding-within-human-dna/We have found that DNA need not be passed directly from parent to child. It can be transducted from other sources.
http://en.wikipedia.org/wiki/Transduction_%28genetics%29http://www.ncbi.nlm.nih.gov/pubmed/10779482Extrapolating these findings to the 600,000 copies of L1 in the genome, we predict that the amount of DNA transduced by L1 represents approximately 1% of the genome, a fraction comparable with that occupied by exons.
So with humans living in close proximity as we do, it is
possible that DNA exchanges can occur without a direct lineage, giving us an even greater ability to exchange useful genetic information.
We don't understand animal (and human) instincts, what they are, and where they come from. Some studies on children suggest that our ability for math is built right into our neurons. I've seen anecdotal evidence of this in my own son. At 4 years of age, he had been taught how to count, add, and subtract and basic fractions like 1/4 and 1/2, etc. But certainly not above that. Yet while playing a game called Monster Rancher, he could tell that after a battle the monster with 31 of 52 hit points left had a greater percentage than a monster with 68 of 115 hit points and announced the winner before it was displayed.
http://discovermagazine.com/2009/nov/17-the-brain-humanitys-other-basic-instinct-math#.Ushbs7QhTDgIn other words, it is very possible that the more we learn, the more we pass on in our DNA and so future generations are able to pick up and use this knowledge easier than their parents, reducing the amount of time that it takes to "learn" the further we advance.
My point is, don't presume to know how far our intelligence and our very structure for retaining information can take us.
For the religious, I believe that it is mandated that we expand into the stars. Certainly if one were to believe in a God, you should have a much greater faith in the ability of his creation to allow us to continue to grow as a species. In this, I believe that the very limited understanding of early humans limited the interpretation of two very old written passages.
1: Be fruitful and multiply and fill the Earth.
In their limited understanding, humans assumed "Earth" meant this planet, I choose to believe that it would refer to all Creation.
2: Come thou and all thy house into the ark; for thee have I seen righteous before me in this generation. Of every clean beast thou shalt take to thee by sevens, the male and his female: and of beasts that are not clean by two, the male and his female. Of fowls also of the air by sevens, the male and the female; to keep seed alive upon the face of all the earth.
Rather than a story of events gone past, I choose to believe that this refers to what we are to do in the future. Build our own ark and fill it with the creatures and plants that we will need to survive and bring them with us as we multiply throughout creation.
So it is written, so shall it be done.