In chapter 1 of Relativity by Einstein, while talking about Geometrical Propositions, he said that the concept of "true" doesn't tally with the assertion of pure geometry.
I didn't understand how the assertions of pure geometry don't tally with the "true" concept. Also in the follow-up lines, he said that we are in habit of designating the word "true" with "real" objects.
The following is the extract from that passage:
We cannot ask whether it is true that only one straight line goes through two points. We can only say that Euclidean geometry deals with things called "straight lines," to each of which is ascribed the property of being uniquely determined by two points situated on it. The concept "true" does not tally with the assertions of pure geometry, because by the word "true" we are eventually in the habit of designating always the correspondence with a "real" object; geometry, however, is not concerned with the relation of the ideas. involved in it to objects of experience, but only with the logical connection of these ideas among themselves.
What does he actually mean by the words: "true", "real" objects, here? Please elaborate by giving an example of such a case from geometry.