My Cumulative Case for the Nonexistence of God
Given the above definitions, I am an atheist in the full sense of
the word. Not only do I lack the belief that God exists, I hold the
opposite, positive belief that God does not exist. Since my atheism
is not a mere lack of belief, I have a burden of proof to provide
arguments or evidence for the truth of atheism just as much as a
theist has the burden of proof to provide arguments or evidence for
the truth of theism.
Anti-atheists sometimes object that one would have to be omniscient
in order to prove that God does not exist. However, as I argue
elsewhere, a person does not have to be omniscient in order to
prove that a concept is incoherent. If a concept entails a logical
contradiction, one does not have to be omniscient in order to show
that. Moreover--and this is a much more important point--I do not
claim to be able to "prove" the nonexistence of God anyway.
Instead, I present evidence which is much more likely if atheism is
true than if theism is true. (In the jargon of the philosophy of
religion, my arguments for atheism are all evidential
arguments.)
In what follows, I will outline a cumulative case for the
nonexistence of God. Although I believe that each of my arguments
constitute good, independent reasons for believing atheism and
rejecting theism, my arguments are even stronger when considered
together. My cumulative case for atheism includes the following
arguments:
1. The History of Science. If there is a single theme unifying the
history of science, it is that naturalistic explanations work. The
history of science contains numerous examples of naturalistic
explanations replacing supernatural ones and no examples of
supernatural explanations replacing naturalistic ones. Indeed,
naturalistic explanations have been so successful that even most
scientific theists concede that supernatural explanations are, in
general, implausible even on the assumption that theism is true.
Such explanatory success is antecedently more likely on
naturalism--which entails that all supernaturalistic explanations
are false--than it is on theism. Thus the history of science is
some evidence for atheism and against theism.
See Keith M. Parsons, Science, Confirmation, and the Theistic
Hypothesis (Ph.D. Dissertation, Kingston, Ontario, Canada: Queen's
University, 1986), p. 46; Paul Draper, "Evolution and the Problem
of Evil" in Philosophy of Religion: An Anthology (3rd ed., ed.
Louis Pojman, Wadsworth, 1997), pp. 223-224.
2. The argument from physical minds. Scientific evidence shows that
consciousness and personality are highly dependent upon the brain.
Nothing mental happens without something physical happening. That
strongly implies that the mind cannot exist independently of
physical arrangements of matter. In other words, we do not have a
soul. And this is exactly what we would expect if naturalism is
true. But if theism is true, then our minds should not depend on
our brains for their existence; we should have souls. Also, if
theism is true, then God is a disembodied mind; God's mind is not
in any sense dependent on physical arrangements of matter. But if
nothing mental happens without something physical happening, that
is evidence against both the existence of souls and the existence
of any being who is supposed to have a disembodied mind, including
God. Therefore, the physical nature of minds is unlikely if theism
is true, but what we would expect if naturalism is true. See
Michael Tooley, "Opening Arguments" The Craig-Tooley Debate.
3. The argument from biological evolution. This argument assumes
the truth of biological evolution; for a defense of that
assumption, see the Talk.Origins archive. To be sure, biological
evolution is logically compatible with theism; God could have used
evolution to create life. But if theism were true, God could have
also used many other methods to create life, methods which are
impossible if atheism is true. In contrast, if atheism is true,
evolution pretty much has to be true. Furthermore, since theism
implies a metaphysical dualism, it is antecedently likely on theism
that minds are fundamentally nonphysical entities and therefore
that conscious life is fundamentally different from nonconscious
life. But this in turn makes it likely that conscious life was
created independently of nonconscious life--that evolution is
false. Thus, the scientific fact of biological evolution is more
likely on the assumption that atheism is true than on the
assumption that theism is true. See Draper 1997, pp. 219-230.
due to this post is tooooooooo long,pls refer such 
http://www.religionisdumb.com/logickills3athargu2.htm