Unsurprisingly, exchanging ideas lead to greater technological progress, but ideas are going to leak one way or another.
It's a good thing for humanity, considering the long threat to our progress is mother nature throwing a really nasty tantrum.
Absolutely true.
We can't really do anything about it except progress as fast as we can without imploding our polity.
But here, I'm going to have to disagree. A higher level of tech sharing actually had a significant number of meaningful impacts on what makes good tech policy.
With no tech sharing, the only question you need to ask about a prospective tech is its value to our polity as compared to the resources or opportunity cost required to attain it. But WITH tech sharing, there are three new parameters we need to consider.
A) What is the effect on our polity for our NEIGHBORS getting this tech?
B) Are we positioned to use this tech more effectively than our neighbors?
C) Could we get this tech from our neighbors without developing it ourselves?
Lets go through this one at a time. The first new question we need to ask when developing a new tech is what happens if/when our neighbors get it? For example, lets say we have a chance to easily push the Siege tech tree. If so, I would suggest MAJOR CAUTION in doing so, because our neighbors getting siege tech
really hurts us, past what we would expect from an average tech. Similarly, if we were only now developing cavalry, I would suggest similar caution, because that tech bleeding to the nomads leads to massive headaches at a minimum.
The second question is whether we have a comparative advantage in using the tech. Does our cultural/economic/environmental/etc status makes the tech particularly useful for us as compared to our neighbors? If so, that means the tech is especially useful to us, since even if everyone got it immediately we would get more out of it than our neighbors.
Last but not least, could we easily get the tech from our neighbors? If so, making it ourselves might be less valuable overall. Why bother spending time and resources on something that we can easily get via tech diffusion?
So all in all, this encourages the following tech policies:
- Focus on techs that you are okay with the people around us getting. Avoid developing techs that would let a polity target our own weaknesses.
- Focus on techs that our polity can use better than other polities. Don't just look at the absolutely value of a tech to us, but also how much value it has to us relative to how much value it has to others. Prioritize techs that synergize well with our Wonders (International Games, Greater Sacred Forest, Dragon Graveyard), our higher-tier Values (Love of Wisdom, Pride in Acceptance, Personal Stewards, Joyous Symphony, etc), and so on.
- Focus on techs that we are less likely to attain via osmosis.