First, you have to convince them that science is a good thing. I have a friend, who literally believes that scientists are either evil people, who's primary goal is to gain power over others by outsmarting them, or, willfully ignorant tools of a predatory political / economic system. To him, big-S Scientists represent a threat to his way of life.

I reminded him that many of my own family members, people that he trusts, work in scientific endeavors; a marine biologist, for example, who has dedicated his life to the wellbeing of the various Pacific salmon species, for the sake of our food supply and forest health. He just lumped me into the second category, insisting that salmon are only managed for profit. That the funding for wild salmon research was being redirected towards improving the yield of fish farms, to the detriment of both the forests of western Canada, and to the detriment of the families and communities that live off of the wild salmon fisheries.

We don't talk much anymore. In order to convince people like this to support science, instead of attacking it, we must convince them of two things: that "real, working" scientists have a conscience, and that they have the power to follow their conscience without losing their status as real, working, scientists.