The essential problem with Michael Ikeda and Bill Jeffreys’ analysis (3.3) is that the authors don’t know what they are talking about. Let me therefore address only one aspect of their paper, namely, the charge that anthropic arguers are mired in a contradiction. Some but not all of the following will use their terminology. Let
L = “The universe exists and contains Life.”
F = “The conditions in the universe are ‘life-Friendly’.”
S = “We are explicitly and directly via a continuous miraculous intervention being kept on life Support.”
T = Theism.
The truth of S would mean that we would be having a direct experience of God keeping us alive supernaturally in a hostile and unfriendly to life universe, rather like Shadrach, Meshach, and Abednego in the fire (Dan 3).
The contradiction being alleged is that, according to the fine-tuning argument, both
P(T | F & L) > P(T) and
P(T | ~F & L) > P(T).
Thus, both F and ~F support T which seems strange. To solve this, consider:
L → F ⊕ S.
Thus, given L, both F → ~S and ~F → S.
(⊕ is “exclusive or,” i.e., either one or the other but not both.)
We can then define:
F & L = “There is naturally, through fine-tuning, supported life.”
S & L = “There is supernaturally supported life.”
Now that we see that, given L, ~F is simply S, the contradiction vanishes:
p(L | T) = 1 = P(F ⊕ S | T);
P(F) is low by the main assumption of fine-tuning; and
P(S) is low, because “a generic Judeo-Christian-Islamic deity” (160) would never be so irrational as to create a universe whose nature is self-contradictory and whose every impulse He would be required to counteract personally by miracles that violate the natural course of events in order to make this universe work.
As a result,
P(T | F & L) > P(T);
P(T | ~F & L) = P(T | S & L) > P(T), or simply
P(T | L) > P(T). QED.