9.2 The Fallacies Of Accident
From 9. Common Fallacies in Clear Thinking by R W Jepson

This is the name given to fallacies arising from neglect of the following rules:

1. What is true of a thing generally is not necessarily true of it in some accidental or peculiar circumstance; and conversely,
2. What is true of a thing in some accidental or peculiar circumstance is not necessarily one of its general or essential properties or characteristics.

In other words, people often forget that circumstances alter cases. For example, (a) Because the laws of England do not generally interfere with the right of citizens to engage actively in politics, it does not thereby follow that civil servants and police are at liberty to do so, for they are in a peculiar position as employees of the state or of local authorities. (b) It would be unjustifiable to defend lying and deceitful propaganda generally, on the ground that it is considered expedient in war-time to issue false information in order to deceive the enemy. Lying undermines the mutual confidence necessary for human intercourse, but the saving of life may outweigh that consideration.