The merits of an argument or the truth of a proposition are independent of the motives and the moral character of the person making the argument or advancing the proposition. Still there are times when I go back to the intellectual drawing board for further scrutiny of fact and logic simply because of the source of the support or opposition that I encounter when I advance a particular argument. The most telling example was a comment on a blog on racism and freedom of speech I received from a KKK member in the US, who wrote he quite agreed with me on freedom of speech, but took a line different from me on racism. Another example was the letter I received in response to a blog by Anne Sibert and myself on the National Health Service , first published in the Daily Telegraph - arguing for its abolition and replacement by a continental European-style comprehensive and mandatory insurance mechanism. The author informed me that we made "...no mention that the NHS has been weakened and weighed down by the enormous number of immigrants entering this country since its formation,...". Perhaps I should have sent him the following answer: I know exactly what you are talking about. Immigrants - they're everywhere. I even got four of them living in my own home: my son (from Peru), my daughter (from Bolivia), my wife (from the USA) and myself (from the Netherlands). Sometimes being judged by the uninvited company you keep can be rather embarrassing. Still, just because Hitler, Stalin, Mao and Pol Pot probably would have agreed with me, most of the time, that two plus two equal four, is no reason for abandoning that bit of arithmetic. So we hold our noses and proceed.