Alexander Hamilton starts Federalist 31 like this:
"IN DISQUISITIONS of every kind there are certain primary truths, or first principles, upon which all subsequent reasonings must depend. These contain an internal evidence which, antecedent to all reflection or combination, commands the assent of the mind."
And he continues by noting this:
"Of this nature are the maxims in geometry that the whole is greater than its part; that things equal to the same are equal to one another; that two straight lines cannot enclose a space; and that all right angles are equal to each other."
More could be said on self-evident truths, but note Lincoln’s use of Euclid in a letter to H.L. Pierce, just before he famously writes "All honor to Jefferson."
"But soberly, it is now no child’s play to save the principles of Jefferson from total overthrow in this nation.
One would start with great confidence that he could convince any sane child that the simpler propositions of Euclid are true; but, nevertheless, he would fail, utterly, with one who should deny the definitions and axioms. The principles of Jefferson are the definitions and axioms of free society. And yet they are denied, and evaded, with no small show of success. One dashingly calls them "glittering generalities" another bluntly calls them ’self evident lies’ and still others insidiously argue that they apply only to ’superior races.’"
All this brought to mind by this short article on Pythagoras. Why do I read Physicsweb? Playing cath-up, flunked physics a couple of times in college. Along with Lincoln, I also regret my want of education, and do what I can to supply the want. Also see this.