Guide Part II, chap 25.

The following is my formulation of what I learned in discussing this chapter with Rabbi Meiselman [I alone take responsibility for all the content.]

There are rules determining when an interpretation of text is acceptable:

1. Peshat [literal, simple] interpretation is to be used, unless there is a compelling reason to reject it.
2. 2. A philosophical demonstration against [any] interpretation is a compelling reason against it. [What counts as a “philosophical demonstration” will be addressed below.]
3. That an interpretation violates central religious principles is a compelling reason against it.
4. There are absolute limits beyond which interpretation cannot pass – even in the presence of compelling reasons against an interpretation, a reinterpretation may be impossible since the reinterpretation passes those limits [See Part I chaps 1-50 and below].

There are five cases to which these principles are applied:

1. Rejecting the peshat of texts that describe G-d in corporeal terms.
2. Rejecting eternity according to Aristotle
3. Rejecting eternity according to Plato
4. The condition under which we would accept eternity according to Plato.
5. The condition under which we would accept eternity according to Aristotle

Here is how the cases come out via the principles:

1. Rejecting the peshat of texts that describe G-d in corporeal terms. there is a philosophical demonstration against G-d’ corporeality, so that is a compelling reason against the peshat describing G-d as corporeal [2]; the alternative interpretation does not violate religious principles [3]; the alternative interpretation is within the acceptable limits [4]
2. Rejecting eternity according to Aristotle: there is no philosophical demonstration of eternity according to Aristotle, so that is no reason reject the peshat [of creation] [1,2]; eternity according to Aristotle violates central religious principles, so that is a compelling reason not to change the peshat [3]; to change the peshat in those texts would pass beyond the acceptable limits of interpretation
3. Rejecting eternity according to Plato: there is no philosophical demonstration of eternity according to Plato, so that is no reason reject the peshat [of Creation] [1,2];
4. The condition under which we would accept eternity according to Plato If there were a philosophical demonstration of eternity according to Plato, there would be a compelling reason to reject the peshat of the verses of creation [1,2]; the reinterpretation would not violate any central religious principles [3]; the reinterpretation would not violate the limits on interpretation [4]
5. The condition under which we would accept eternity according to Aristotle: If there were a philosophical demonstration of eternity according to Aristotle, there would be a compelling reason to reject the peshat of the verses of creation [1,2]; but the reinterpretation would pass beyond the limits of acceptable interpretation – and then we would not reinterpret [and it is not clear what we would do – see below].

Now here they are again, with the passages from the text inserted:

6. there is a philosophical demonstration against G-d’ corporeality, so that is a compelling reason against that peshat [2] the Incorporeality of God has been demonstrated by proof:; the alternative interpretation does not violate religious principles [3] Secondly, our belief in the Incorporeality of God is not contrary to any of the fundamental principles of our religion: it is not contrary to the words of any prophet.; the alternative interpretation is within the acceptable limits [4] nor is it impossible or difficult to find for them a suitable interpretation
7. there is no philosophical demonstration of eternity according to Aristotle, so that is no reason reject the peshat [of Creation] [1,2]But the Eternity of the Universe has not been proved; eternity according to Aristotle violates central religious principles, so that is a compelling reason not to change the peshat [3] we should necessarily be in opposition to the foundation of our religion, we should disbelieve all miracles and signs, and certainly reject all hopes and fears derived from Scripture,; to change the peshat in those texts would pass beyond the acceptable limits of interpretation unless the miracles are also explained figuratively. The Allegorists amongst the Mohammedans have done this, and have thereby arrived at absurd conclusions and But if we assume that the Universe has the present form as the result of fixed laws, there is occasion for the above questions: and these could only be answered in an objectionable way, implying denial and rejection of the Biblical texts, the correctness of which no intelligent person doubts.[4]
8.  there is no philosophical demonstration of eternity according to Plato, so that is no reason reject the peshat [of Creation] [1,2]But the Eternity of the Universe has not been proved
9. If there were a philosophical demonstration of eternity according to Plato, there would be a compelling reason to reject the peshat of the verses of creation [1,2]; the reinterpretation would not violate any central religious principles [3] If, however, we accepted the Eternity of the Universe in accordance with the second of the theories which we have expounded above (ch. xxiii.), and assumed, with Plato, that the heavens are likewise transient, we should not be in opposition to the fundamental principles of our religion: this theory would not imply the rejection of miracles, but, on the contrary, would admit them as possible.; the reinterpretation would not violate the limits on interpretation [4]We should perhaps have had an easier task in showing that the Scriptural passages referred to are in harmony with the theory of the Eternity of the Universe if we accepted the latter, than we had in explaining the anthropomorphisms in the Bible when we rejected the idea that God is corporeal.
10. If there were a philosophical demonstration of eternity according to Aristotle, there would be a compelling reason to reject the peshat of the verses of creation [1,2] If, on the other hand, Aristotle had a proof for his theory, the whole teaching of Scripture would be rejected, and we should be forced to other opinions.; but the reinterpretation would pass beyond the limits of acceptable interpretation – and then we would not reinterpret [though it is not clear what we would do – see below.

The quotes under g clearly illustrate limits on interpretation, and this last quote under j is absolutely compelling: even a philosophical demonstration contradicting the whole of the content of the Torah would not lead to reinterpretation!

  

It remains to comment on the Rambam’s meaning for “philosophical demonstration”. It is clear from Part 2 chapter 17 that any demonstration relying of the assumption of the uniformity of the laws of nature in the past would not count. On the other hand, the Rambam’s own demonstrations start from presently observed realities and use natural physical/philosophical reasoning, so something like that would count. In any case, the age of the universe and evolution and relating theorizing clearly will not count.