Letter to Castelli (excerpt)

December 21,  1613

....As therefore, the Holy Scriptures in many places not only admit but actually require a different explanation for what seems to be the literal one, it seems to me that they ought to be reserved for the last place in mathematical discussions.  For they, like nature, owe their origin to the Divine Word; the former is inspired by the Holy Spirit, the latter as the fulfillment of the Divine commands; it was necessary, however in Holy Scripture, in order to accomodate itself to the understanding of the majority, to say many things which apparently differ from the precise meaning.  Nature, on the contrary, is inexorable and unchangeable, and cares not whether her hidden causes and modes of working are intelligible to the human understanding or not, and never deviates on that account from her prescribed laws.  It appears to me therefore that no effect of nature, which experience places before our eyes, or is the necessary conclusion derived from evidence, should be rendered doubtful by passages of Scripture which contain thousands of words admitting of various interpretations, for every sentence of Scripture is not bound by such rigid laws as is every effect of nature....

Since two truths can obviously never contradict each other, it is the part of wise interpreters of Holy Scripture to take the pains to find out the real meaning of its statemments, in accordance wtih the conclusions regarding nature which are quite certain, either from the clear evidence of sense or from necessary demonstration.  As therefore the Bible, although dictated by the Holy Spirit, admits, from the reasons given above, in many passages of an interpretation other than the literal one; and as, moreover, we cannot maintain with certainty that all interpreters are inspired by God, I think it would be the part of wisdom not to allow any one to apply passages of Scripture in such a way as to force them to support, as true, conclusions concerning nature the contrary of which may afterwards be revealed by the evidence of our senses or by necessary demonstration.  Who will set bounds to man's understanding?  Who can assure us that everything that can be known in the world is already known?  It would therefore perhaps be best not to add, without necessity, to the articles of faith which refer to salvation and the defence of holy religion, and which are so strong that they are in no danger of having at any time cogent reasons brought against them, especially when the desire to add to them proceeds from persons who, although quite enlightened when they speak under Divine guidance, are obviously destitute of those faculties which are needed, I will not say for the refutation, but even for the understanding of the demonstrations by which the higher sciences enforce their conclusions.

I am inclined to think that the authority of Holy Scripture is intended to convince men of those truths which are necessary for their salvation, and which being far above man's understanding cannot be made credible by any learning, or any other means than revelation by the Holy Spirit.  But that the same God has endowed us with senses, reason, and understanding, does not permit us to use them, and desires to acquaint us in any other way with such knowledge as we are in a position to acquire for ourselves by means of those faculties, that it seems to me I am not bound to believe, especially concerning those sciences about which the Holy Scriptures contain only small fragments and varying conclusions; and this is precisely the case with astronomy, of which there is so little that the planet are not even all enumerated....

Galileo Galilei

Source: Karl Von Gebler, Galileo Galilei, p. 46-48 (1879).

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