other than A. And when they are put in this form, it is, I think, easy to see why they should be confused: you have only to confuse "must" or "is necessarily" with "would necessarily be." And their connexion with the question of external relations can be brought out as follows: To maintain external relations you have to maintain such things as that, though Edward VII was in fact father of George V, he _might_ have existed without being father of George V. But to maintain this, you have to maintain that it is _not_ true that a person who was _not_ father of George would necessarily have been other than Edward. Yet it is, in fact, the case, that any person who was not the father of George, _must_ have been other than Edward. Unless, therefore, you can maintain that from this true proposition it does _not_ follow that any person who was _not_ father of George _would necessarily_ have been other than Edward, you will have to give up the view that Edward might have existed without being father of George. By far the most important point in connexion with the dogma of internal relations seems to me to be simply to see clearly the difference between these two propositions (1) and (2), and that (2) does _not_ follow from (1). If this is not understood, nothing in connexion with the dogma, can, I think, be understood. And perhaps the difference may seem so clear, that no more need be said about it. But I cannot help thinking it is not clear to everybody, and that it does involve the rejection of certain views, which are sometimes held as to the meaning of "follows." So I will try to put the point again in a perfectly strict form. Let P be a relational property, and A a term to which it does in fact belong. I propose to define what is meant by saying that P is internal to A (in the sense we are now concerned with) as meaning that from the proposition that a thing has not got P, it "follows" that it is _other_ than A. That is to say, this proposition asserts that between the two properties "not having P" and "other than A," there holds that relation which holds between the property "being a right angle" and the property "being an angle," or between the property "red" and the property "coloured," and which we express by saying that, in the case of any thing whatever, from the proposition that that thing is a right angle it follows, or is deducible, that it is an angle. Let us now adopt certain conventions for expressing this proposition.