With the many failings of Christians in full view of the public, it is no wonder there are so many that doubt there is a true and unchanging God. (religion.blogs.cnn.com)
Then there are questions regarding the nature of mind and matter as such, the concepts of becoming, and of unchanging natures, the philosophical question of the nature of the substantial soul and its relation to the body. (religion-online.org)
Since Francis is not a doctrinal relativist, he does not hold the truth itself to be variable with time and place, but only its formulations, urging an expansion of its expression, namely, «seeking ways of expressing unchanging truths in a language which brings out their abiding newness.» (firstthings.com)