Is it farther or further?
late 16c. variant of Middle English proponen "to put forward" (late 14c.), from Latin proponere "put forth, set forth, lay out, display, expose to view," figuratively "set before the mind; resolve; intend, design," from pro- "before" (see pro-) + ponere "to put" (see position (n.)). Perhaps influenced in form by compound, expound. Related: Propounded; propounding.