I have long subscribed to Isaiah Berlin’s principle of incommensurabilty. That is to say, some differences of opinion are based on such radically different premises that even the most sustained efforts in reasoning together will find great difficulty in succeeding: there is no common ground. In practice, though, the principle need not be a counsel of despair. Take same-sex marriage, for example, where as recently as ten years ago differences seemed unbridgeable. But in fact they were bridgeable, through the ideas of equality (a foundational value in our society, however neglected in practice), and in some cases friendship or consanguinity, when a close friend or relative proved to be gay or lesbian and would benefit from marriage.

 

By contrast, in the matter of the current passions aroused by the death of Margaret Thatcher, there seems to be no bridge to soften or erase incommensurability.  Hence the bitterness of the conflict.