They were talking about modern Cosmology and the agreed fact that the universe seems to have been designed within very very very tight margins so that we should exist. Those who do not want to draw the conclusion that God designed it go for, instead, the Anthropomorphic Principle: We are here so of course the universe is like it is. Other universes that we can know nothing about may also exist or have existed. (The tense opens up a whole lot of questions about time which cannot be pursued)
But if it does lead to God that is not enough and Miller is right. The
belief in a God who rewards those who obey Him, leaves them in the lurch
when they don't and encourages the destruction of the rest, as in much
of the Old Testament, cannot be rationally sustained. Belief in the existence
of God only makes sense when we see Him crucified in Christ. God in Christ
took upon Himself the penalty for sin, not because His separate Father
required it but because we needed it and continue to need it.
Here we do have to pursue the time dimension, poetically not scientifically
because we cannot know about Heaven any other way. The Cross is timeless
and is not expunged by the Resurrection. Christ carried His wounds into
Heaven and they shall not be removed until He returns in Glory in the final
victory.
In this case written by John Bowring and first published in 1825 based on Galations 6 v14:
In
the Cross of Christ I Glory, towering over the wrecks of time
All the light of sacred story
gathers round its head sublime
When the woes of life o'ertake
me, hopes deceive and fears annoy
never shall the Cross forsake
me, Lo it glows with peace and joy
Bane and blessing, pain and pleasure
by the Cross are Sanctified;
Peace is there that knows no
measure,
Joys that through all time abide.