Thomas F. Torrance in his book Christian Theology & Scientific Culture offers up, as usual, some very interesting thoughts on the relationship between Science and Christian Dogmatics, or what we might call Systematic Theology. This book of his is comprised of a series of lectures he delivered at The Queen’s University, Belfast in 1980; officially titled: The Theological Lectures at The Queen’s University, Belfast for 1980. Per Torrance’s normal predilection he refers to his influences: Michael Polyani, James Clerk Maxwell, Albert Einstein, et. al.
The portion I want to quote from comes towards the last third of the book where Torrance, drawing off of his interaction with these lights indeed offers up a ‘theology of light’ as an analogue of the uncreated light of God. In this instance, the instance I will quote him in, he is applying the gains made by engaging in a theology of light as applied to God’s ‘Grace’. Torrance, you will notice from the quote refers to ‘constancy’, he is referring to the constancy of the speed of light (no matter the variables it encounters within its contingent frame of reference). Torrance writes:
Another aspect of God’s Constancy which we may consider is his Grace. God is wholly and unconditionally gracious. Grace may be described as the consistently free and unreserved self-giving of God in love to all alike, which is not conditioned or controlled in any way whatsoever by the worth of its object. It is the constant and ceaseless out-flow of the Love of God which has no other reason for its movement than the Love that God is, and is therefore entirely without respect of persons and irrespective of their reactions. In the Biblical tradition this conception of the undeserved Grace of God is allied to an understanding of a covenant relationship of steadfast love and truth between God and his people. While covenant relationship was disclosed though its concrete realisation in God’s relations with historic Israel, it has been unilaterally set up by God between himself and all mankind, to which he remains everlastingly failtfuland [sic] which he unilaterally upholds no matter whether the covenant partner fulfils his part in the relationship or not. God can no more break his covenant of Love and Truth with mankind than he can cease to be God. The unilateral character of his covenant relationship and the unconditional nature of Grace on which it rests have steadily met with resistance in ancient and modern times on the part of men and women. Through deeply ingrained habits (that is, by virtue of our original sin) we want in some measure to deserve or earn the Grace of God—hence even the prodigal cannot repent without asking his father to take him on as one of his ‘hired servants’. Thus we tend regularly to interpret God’s unilateral covenant mercies within a frame of thought, such as the so-called ‘covenant of works’ invented by Calvinists, in which the self-giving of God in undiluted Grace is held after all to be conditional on our human responses. However, it was precisely in order to save us from that state of affairs, in which we are trapped in our own self-regard and self-will, that Jesus came preaching the Gospel of the sovereign unconditional Grace of God which is poured out freely on all people alike whether they are reckoned to deserve it or not. Indeed, if any discrimination is to be made it is made in favour not of the righteous but of sinners, not of the healthy but of the sick. This radical objectivity of God’s Grace was stressed by Jesus when, for example, in his Sermon on the Mount he taught that God ‘makes his sun to shine on the evil and the good, and sends rain on the just and the unjust’. That is to say, out of his sheer unmerited Grace God makes his uncreated Light to shine in the same free, invariant and equable way on all that he has made, but such complete impartiality on the part of God’s Grace has the effect of relativising all our interpretations of it.
Just as the constancy of created light reflects and points beyond itself to an antecedent objective reality of God’s uncreated light, the constancy of God’s objective and unrelenting Grace is not something we can harness or manipulate. We can’t capture it by mechanisms of theological constructs intended to service our need to still have some cooperative part within God’s salvific reality; we can’t say that God’s Grace is for those people, but not these other people; we can’t objectify Grace in transubstantiated elements like bread and wine, or even the Bible; we can only allow it to penetrate deeply into the fabric of our souls through the vicarious humanity and faith of Christ for us and say: thank you, dear Lord.
Torrance leaves off his quote with a critique of the Federal theology concept of the covenant of works; a system of thought that actually does indeed undercut a concept of God’s Grace, a Grace that by definition relativizes all of our attempts to do exactly that: i.e. speak of it in such a way that we can control it as an aspect of our appropriation of God’s good salvation. We cannot. That is Torrance’s good point.
 Thomas F. Torrance, Christian Theology & Scientific Culture (Belfast: Christian Journals Limited, 1980), 82-3.