though at the same time, and in the same population, the existence of other planets full of conscious beings was basically non-controversial:
Life, as it exists on Earth in the form of men, animals and plants, is to be found, let us suppose in a high form in the solar and stellar regions.
Rather than think that so many stars and parts of the heavens are uninhabited and that this earth of ours alone is peopled—and that with beings perhaps of an inferior type—we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God, who is the center and circumference of all stellar regions.
Of the inhabitants then of worlds other than our own we can know still less having no standards by which to appraise them.
Life, as it exists on Earth in the form of men, animals and plants, is to be found, let us suppose in a high form in the solar and stellar regions.
Rather than think that so many stars and parts of the heavens are uninhabited and that this earth of ours alone is peopled—and that with beings perhaps of an inferior type—we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God, who is the center and circumference of all stellar regions.
Of the inhabitants then of worlds other than our own we can know still less having no standards by which to appraise them.
Nicholas of Cusa, c1440; Cardinal and Bishop