“The thing that really is trying to tyrannize through government is Science. The thing that really does use the secular arm is Science. And the creed that really is levying tithes and capturing schools, the creed that really is enforced by fine and imprisonment, the creed that really is proclaimed not in sermons but in statutes, and spread not by pilgrims but by policemen – that creed is the great but disputed system of thought which began with Evolution and has ended in Eugenics. Materialism is really our established Church; for the Government will really help it to persecute its heretics.”

Source: Eugenics and Other Evils (1922), Ch. VII: "The Established Church of Doubt" (pp. 76-77). https://books.google.com/books?id=m2xaAAAAMAAJ&pg=PA76&dq=%22the+thing+that+really+is+trying+to+tyrannise+through+government+is+science%22&hl=en&sa=X&ved=0ahUKEwj9uKmM_6jMAhUHgj4KHZr3DW0Q6AEILzAD#v=onepage&q=%22the%20thing%20that%20really%20is%20trying%20to%20tyrannise%20through%20government%20is%20science%22&f=false Dale Ahlquist, president and co-founder of the American Chesterton Society, commenting of this passage writes: "Eugenics is also about the tyranny of science. Forget the tired old argument about religion persecuting science. Chesterton points out the obvious fact that in the modern world, it is the quite the other way around." http://www.chesterton.org/lecture-36/ Lecture 36: Eugenics and Other Evils