■ A deductive argument works on the principles of logical

necessity. Every stage of a deductive argument must be the

only logical step available.

■ The premise is a key factor in a deductive argument.

■ The ontological argument works from a definition of God as

its premise.

■ Indeed, it is the premise of the argument that has faced the

most challenges.

■ Anselm Proslogion 2 (P2): God’s existence is a logical

necessity.

■ Anselm defines God as ‘that-than-which-none-greater-can-be-

thought’ (TTWNGCBT) i.e. the greatest being imaginable.

■ To be TTWNGCBT it is logically necessary for God to exist since:

■ (1) There are two ways that we could conceive of God.

■ (a) TTWNGCBT could merely be a concept (mind).

■ (b) TTWNGCBT could also be both a concept and a reality (mind

and reality).

■ (2) If TTWNGCBT were simply a concept (mind only) then we

can think of something greater i.e. TTWNGCBT that is both

mind and reality.

■ (3) But this is illogical since TTWNGCBT (mind) cannot be

TTWNGCBT because there is something greater TTWNGCBT

(mind and reality).

■ (4) Therefore, to be TTWNGCBT God must exist in both the

mind and reality.

■ The Anselm Proslogion 3 (P3): God’s non-existence is a

logically impossibility.

■ In some ways this is more straight-forward than Anselm’s first

argument.

■ This argument builds upon TTWNGCBT and the notion of

existence.

■ Existence has a limit in that it is also possible for non-existence.

■ However, for God to be TTWNGCBT God’s existence must be a

logical necessity – not because it is the opposite of contingent

existence as some often propose (that is the cosmological argument) – but because it is impossible to think of TTWNGCBT as not-existing in the first instance.

■ TTWNGCBT must exist because TTWNGCBT cannot be thought

of as not-existing as this would mean that there exists a

TTWNGCBT for which it is possible to not-exist but that it is also

possible to think of a greater TTWNGCBT which cannot not

exist. This is illogical.

■ Therefore, to be TTWNGCBT God must be a being that cannot

not exist.

■ This being, by very nature of being TTWNGCBT must be the

only being of its kind, that is, unique and ‘the highest degree’ of

existence.

■ Anselm finishes his argument by stating: ‘To thee alone,

therefore, it belongs to exist more truly than all other beings,

and hence in a higher degree than all others. For, whatever

else exists does not exist so truly, and hence in a less degree it

belongs to it to exist.’ (P3)

Key quotes:

-“For, it is one thing for an object to be in the

understanding, and another to understand that the

object exists.” (Anselm P2)

-“…there is no doubt that there exists a being, than

which nothing greater can be conceived, and it exists

both in the understanding and in reality.” (Anselm P2)

-“…it is possible to conceive of a being which cannot

be conceived not to exist; and this is greater than one

which can be conceived not to exist.”

(Anselm P3)

-“…There is, then, so truly a being than which nothing

greater can be conceived to exist, that it cannot even

be conceived not to exist…”

(Anselm P3)

-“…whatever else there is, except thee alone, can be conceived not to exist.” (Anselm P3)

Key arguments/debates:

-The argument is logically sound; however, there is some debate about the

validity of the initial premise.

-Some would say the argument presented by Anselm is simply a matter of faith based upon the true (hidden) premise ‘if’.

-Some argue that the argument has no basis in, or is so far removed from reality.

Key questions:

-Can a deductive argument be appropriate for empirical notions of

existence?

-£1 + £1 = £2; however, is the demonstration that I ‘have’ £2 a different

matter altogether?