Did "awesome" suddenly become synonymous with "fundamentally wrong in every possible way"? Since Mr. Feynman isn't here to answer and you seem to agree so strongly with him, I'll simply address this to you instead of him. Full disclosure: I am a social scientist, which is why I'm so curious.
Do you honestly think that social scientists just sit at a typewriter (computer nowadays) and make shit up? That there's no theorizing, no testing, no data? And then nobody else ever cross-checks this, never tries to replicate results? Have you ever sat down and read a social science publication? Any journals? Any books published for the academic market?
I ask these questions because otherwise I cannot even fathom how you can draw these conclusions. I don't assume you have any advanced studies in sociology or the like, so why do you assume that you know what they're doing and that they're making things up?
Let's try the example given in that rant: that organic food is better for you than non-organic food. A basic problem with his argument: who's researching that? Which social science deals with questions of nutrition? I don't mean the social effects of organic farming, I mean who is going to see if organic food is more nutritious than the alternative? I don't think any of them do, at all. Economists might ask about the economic effects of organic farming, or political scientists about the political effects of malnutrition, but neither of them are going to look at whether it's better for people in a biological way. They'll go across campus and ask somebody in the food science department, because those are the people who actually would research this sort of thing. (Or the nutrition department, or the health department, or whatever physical science actually looks at issues of organic nutrition.) Social scientists might use these findings in a study to look at the social effects of organic farming, but that's a different question entirely.
Some people on /. seem to have a desire to pit the physical sciences and social sciences against each other, but I say that's silly. They look at different phenomena, but each contributes valuable knowledge to the world. Not like those jerks in the fine arts departments. (I'm kidding, please put those instruments down!)