Overall I really like the concept of the site!
I'd recommend not just having theory being the only negative option but including a 'False' or 'Disagree' option as many of the topics seem to be opinion. You could also have each option be color coordinated with the green(positive) orange(undecided) red(negative) that you've defined in your current logo. I would adjust the brightness of each color so that you can then use these colors as a background on each topic based on user input. Either as a gradient or simply as a % block. With this you can hide initial % on each button until after the user hovers over the topic or individual buttons. Also adding an option to hide other user's choices until you have made ours would add an extra layer incentive for interaction for your users.