Jordan
Howard Sobel Logic
and Theism. Arguments For and Against Beliefs in God.
Within
natural theology and philosophy of religion arguments for and against the
existence of God have been given, claiming that someone following only the lead
of reason would see thus that there is a God or that there cannot be. There are
quite some of these arguments and the literature is corresponding to the
importance of the matter in point vast. Jordan Sobel has written a monumental
study of some 650 pages (the last hundred being notes) outlining the most (in)famous
of these arguments. The book provides a detailed reconstruction of each argument
and discusses in a balanced way proposal for improving the argument in question.
Not only giving its length, but more so the succinct and precise way Sobel puts
the matter this is by far the most comprehensive and detailed discussion of
arguments on God that is around (in a single volume). As the title suggests
Sobel uses the tools of logic to reconstruct the arguments. The main text of a
chapter contains the discussion, the formalization of the argument in question
and in most cases informal reasoning for or against belief in God, appendices in
the chapters set out the tools used and present the proper proofs for the claims
made or proper formal renderings of the informal proofs given. The logic used
consists mainly of First Order Logic in a somewhat unusual natural deduction
format, that one can, however, easily adapt to. Some arguments need some basic
modal logic, others use basic set or probability theory and Baysianism. Anyone
who has mastered a course in First Order Logic and has heard of the other fields
should have no difficulties with this. (There are, as usual in books with lots
of formula, a few typos, but the reader following the text can always guess what
should be written there.) I recommend this book to anyone being interested
either in the philosophy of religion as such or in the painstaking
reconstruction of non-trivial philosophical arguments.
The book is divided in five parts. The first chapter being a part of its
own concerns the concept of divinity. The second part concerns arguments for the
existence of God and consists of a chapter on the classical ontological
arguments, one on modern modal ontological arguments, one on Gödel’s
ontological proof, one on Aquinas’s proof by first causes, one on cosmological
arguments, one on arguments from design, and a chapter on miracles. The third
part deals with the common conception of God, and consists of one chapter
dealing with the concept of omnipotence and one dealing with omniscience. The
fourth part contains the arguments against the existence of God, one chapter
dealing with evidential arguments from evil, one dealing with the logical
problem of evil. The fifth part dealing with practical arguments for and against
God consists of a single chapter presenting several versions and refinements of
Pascal’s wager. What is missing is a chapter or an introduction reflecting on
what the book is doing. This is unfortunate for two reasons. First, religious
people supposedly do not believe because God was proven to them, they do not
expect Him to be disprovable, the very idea of approaching faith in this
philosophical (i.e. fallible) manner is anathema for a stout believer. Thus it
is necessary to reflect why there is natural theology and who uses it for what (as
Aquinas claims that it supports belief …). Secondly, no argument
establishes just a conclusion. An argument establishes a conclusion given its
premises and the logic used. So given some conclusion supposedly
establishing the existence or non-existence of God a critic can always either
turn the argument around seeing it as an argument against one of the premises or
can claim that either the logic used is not sound, or at least not sound as
applied in this area. The later option is the more live as we have seen a number
of non-classical and philosophical logics – and even set theories – coming
up in the last century. Thus the discussion of some argument for or against God
has to reflect both options. This methodological meta-reflection is missing in
the book, but Sobel in fact often tries to cover both ways of reaction (e.g.
when discussing the employed set theoretical principles in arguments against the
consistency of omniscience).
Sobel does not give concluding recommendations whether one should or
should not believe in God, but he dismisses some of the traditional arguments
and sees greater strength in others. Some classical ontological arguments (e.g.
Descartes’) are rejected, since the move to define something into existence
seems not only too suspect, but actual can be shown to fail logically in
misusing existential quantification. Others (e.g. one going back to Anselm)
presuppose that what is conceivable is possible. This, however, is a very
controversial thesis itself. And on this assumption the modern modal versions (e.g.
by Plantinga) of the ontological
argument are – despite their formal sophistication – no improvement. Too
permissive tools of cross-world definition of concepts deliver not only God, but
dragons and whatever you like to have around! Gödel’s proof, on the other
hand, really works (given the logical background), but the concept of
‘God-like being’ that is employed is much too wide to resemble the classical
concept of God – Gödel proofs too much. Arguments from first causes rely on a
questionable principle of sufficient reason, a strong version of it (in Leibniz)
yields breakdown of all modal distinctions (i.e. makes the world itself
necessary). A principle of complete reasons goes against the existence of
contingent truths. Arguments from design received their death blow from
evolutionary explanations, Swinburne’s cumulative design argument contains a
fallacy in probabilistic reasoning with cumulative evidence. Hume’s argument
against believing in miracles can be given a formally valid rendering. The
common conception of God Sobel takes to include a strong conception of
omniscience and omnipotence, where ‘strong’ is spelled out either as ‘at
all times’ or ‘essentially’. These distinctions generate – not only in
these two chapters – several versions of the argument under discussion.
Essential omnipotence turns out to be definable, but not applicable, since the
famous counter-argument of making a stone one cannot lift goes through. Grim’s
more recent arguments against omniscience arguing by Cantor’s Theorem against
the existence of a set of truths and thus against the possibility of a set of
all ‘things’ an omniscient being knows can be modified in a way that relies
less on ontological controversial assumptions about propositions and that uses
weaker set-theoretical principles. Still these (valid) arguments make use of
diagonalization assumptions that may be at least controversial. Sobel finds
fault with Rowe’s evidential argument from evil, but assents to the
incompatibility of evil and the existence of a perfect being. The wagers
in the manner of Pascal depend heavily on the background assumptions a person
the wager is offered to accepts. Once these assumptions (like God rewarding the
wilful believer) are made decision theoretic reasoning delivers a verdict on
believing or not. Sobel just rejects the objection that one cannot make oneself
believe something by will.
Sobel
often highlights what a defender of faith had to assume to get rid of the
arguments against God. (This concerns the general remark above, how arguments
may be turned around or re-interpreted.) In the probabilistic cases like the
miracle reports or design arguments the force of the arguments rests on the
prior probabilities someone may assign. In this way probabilistic arguments can
also be rejected or turned around! If, for
example, the prior probability assigned to God’s existence is much higher than
the probability of His non-existence then the existence of evil may not raise
the probability of non-existence to over 50% (which may be taken as the crucial
mark).
Sobel seems inclined to see the balance of the arguments to be in favour
of rejecting God’s existence, this being taken as the existence of a perfect
being as conceived in philosophical theology. Some of the arguments live from
the strict understanding of being perfect, omnipotent or omniscient. Whether
these arguments have force against a somewhat reduced concept of God – as is
supposedly the case in Christianity or Islam – is an open question. Sobel sees
this point, but does not address such historical conceptions of God and their
reply to the arguments given. That is understandable, since this may have taken
some more hundred pages, however the force of what the arguments against
omnipotence, omniscience (in the third part) and the arguments from evil (in the
fourth part) show thus has to be taken with caution. Defenders of faith like van
Inwagen start here. Someone like van Inwagen, who certainly shares Sobel’s
rejection of equating conceivability with possibility, would add further
scepticism on modal epistemology. Sobel’s stepwise improvement of the logical
argument from evil, for example, relies not only on us knowing that what we
consider evil is evil, but on stepwise weakened major premises one may
increasingly doubt (going from ‘Evil exists’ to ‘If there is a best
possible world, the world is improvable’).
Anyone taking on the task of widening the scope of the arguments towards
criticising Christianity or Islam, and anyone taking on the arguments from the
mutual support of, say, the claims of a Christian weltanschauung should
start with Sobel’s book. Since 650 pages are a lot one may start with the
chapters dealing with the ontological arguments. Here you can see the strength,
quality and sometimes originality of Sobel’s work best.
Manuel Bremer
Philosophisches Institut
Heinrich-Heine-Universität Düsseldorf
Universitätsstraße 1
40225 Düsseldorf
bremer@mbph.de