Arguments for God's Existence from Contingency

[Neo-Scholastic]

The concept of 7' is in our heads by definition, that's what concepts are. '7' is not independent of our minds, because without a mind, there's no concept of '7'. If there were 7 rocks on the beach without a mind to count them or decide to focus on how many rocks there are instead of grains of sand, or distinguish grains of sand from rocks, or limit the number of rocks to those visible to a person standing on that beach; etc. '7' would be meaningless.

In order for the mind to form a concept by abstraction there must be some abstractable quality.

Can any of you explain what exactly "necessity of its own nature" means? I googled it, found pages and pages of the religious using the statement/position in their arguments but never really stating what it is or why it is.

They are trying to distinguish between something necessary because of contingency versus something necessary in-and-of-itself. For the traditional example, if there is a son, then by necessity there is a mother and father. Or in a Hegelian sense, some types of necessity depend on a dialectical relationship. There are no masters without slaves nor slaves without masters. Whether the set of necessary by nature is empty, has only one, or several members is a matter of debate. Such members could include Being-Itself, the Principle of Non-Contraction, Primal Matter, or other such things.

The universe exists because it exists. Whether it is necessary is immaterial.

Whether or not it is necessary is in fact important. The fundamental question is how things are able to both persist and change. Taking the physical universe's existence for granted implies EITHER that it is stasic (Parmenides) OR that it is nothing but change (Heraclitus). Neither is coherent. This dilemma is resolved by recognizing that the physical universe is contingent. The next step is reasoning about what exactly it is and the nature of that on which the physical universe depends.