also openminded, "having an unreserved mind; frank, candid," also "having a mind accessible to new views, not narrow-minded, unprejudiced," 1828, first recorded in Carlyle; from open (adj.) + -minded. Figurative use of open (adj.) with reference to hearts, hands, etc. is from early 15c. Related: Open-mindedly; open-mindedness.
Could we hope that, in its present disjointed state, this emblematic sketch ["Wanderjahre"] would rise before the minds of our readers, in any measure as it stood before the mind of the writer; that, in considering it, they might seize only an outline of those many meanings which, at less or greater depth, lie hidden under it, we should anticipate their thanks for having, a first or a second time, brought it before them. As it is, believing that to open-minded, truth-seeking men, the deliberate words of an open-minded, truth-seeking man can in no case be wholly unintelligible, nor the words of such a man, as Goethe, indifferent, we have transcribed it for their perusal. [Carlyle, "Goethe," 1828]