Where does discussion come from? What makes us choose one stance over another? This is a really, really cursory look at where our opinions come from, although I think that it is currently far too vague and general a model to get any kind of useful feedback from. However, it may help in breaking down my thoughts, or others. It's also kind of upside-down.

Technology This is a decent starting point, assuming that we should ask "How should we use it?" rather than "Should we build it or not?".

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gives rise to
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Debate Is an individual's point of view on a particular issue pre-determined prior to that issue being presented?

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which is determined by
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Opinion I think we have a moral standpoint, which we then try to fit any particular issue into, rather than approaching an issue purely from a fresh, self-contained (within the issue) perspective. This makes sense, as technology simply exists within established moral laws. Or rather, what we call...

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which is decided by
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Culture Opinion-to-Culture is the biggest jump here, as culture encapsulates way too much for this summary to be of use. However, it makes sense that different cultures have completely different morals, and so the majority of opinion is decided according to which culture it is in.

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which arises from
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Environment This is actually the blurriest jump in the chain. Is geographical location and environment ultimately the driving force behind how a culture will develop? There are definitely extremes, e.g. a technologically-advanced culture arises less easily in very low temperatures, or any other environment in which the culture spends most of its time on merely surviving.

So, I hypothesise, for longest term change in opinion, the environment should be altered. However, as we have not yet mastered terraforming, it is far easier to install butterflies to alter the winds of culture, rather than nature itself, and it is evident that the architecture that we build around us is an influential factor of our culture, and perhaps therefore our opinions. We control what we can.