The first cause argument

[Polymath257]

You are just avoiding understanding what a per se causal series is by trying to pick apart the analogy of light reflecting off moons but originating from a sun.
If I had picked on the per accidens causal series of generations of people that @PearlSeeker presented I would have argued it is clearly not per accidens. I refrained because I realized the point being made wasn't about the efficacy of the analogies.

My point ultimately is that the 'per se' and 'per accidens' dichotomy is a false one. There is causality, which is always a type of interaction. And there is no reason to think that the causal chain is finite.

Ultimately, the goal is to find a reason for existence itself. But there *cannot* be such an explanation: to explain would require something that does not exist giving rise to something that does. So there *must* be something (perhaps many things) that simply exist with no explanation or else there is an infinite regress of causes.

I actually suspect both to be the case: that there are some infinite causal chains and also a great number of uncaused causes.

 

[PearlSeeker]

Suppose that a star explodes that is 500 light years away and emits a tremendous amount of light. The light travels to the Earth, is reflected off of the moon, and illuminates a room. But, at the time the light is reflected off of the moon, the star that exploded no longer exists: it exploded 500 years ago. So, the illumination of the room does NOT require the continued existence of the source that makes the light. it only requires the light itself.

The only difference between this and the example of the sun is that the travel time for light from the sun is only 8 minutes or so as opposed to 500 years. The sun could cease to exist and the room would be illuminated by the light that was still traveling to the room.

"So, it is ultimately their instrumental character, and not their simultaneity, which makes every member of a per se ordered causal series other than the first depend necessarily on the first." (Edward Feser)

In your example it doesn't matter that the explosion of the star and lighting of the moon is 500 years apart. We still have a per se series because lighting of room by moon essentially depends on lighting of moon by star.

 

[Polymath257]

"So, it is ultimately their instrumental character, and not their simultaneity, which makes every member of a per se ordered causal series other than the first depend necessarily on the first." (Edward Feser)

In your example it doesn't matter that the explosion of the star and lighting of the moon is 500 years apart. We still have a per se series because lighting of room by moon essentially depends on lighting of moon by star.

And the ability of John II to procreate depends essentially on the fact that John I was able to procreate. If John I didn't procreate, John II would not either. In fact, John II would not even exist.

Again, I don't see a significant difference.

 

[PearlSeeker]

And the ability of John II to procreate depends essentially on the fact that John I was able to procreate. If John I didn't procreate, John II would not either. In fact, John II would not even exist.

Again, I don't see a significant difference.

Causal relations are different. In accidens series w being A causes x to be B, x being C causes y to be D, y being E causes... Relations are not transitive. John I causes John II. But John I doesn't cause John III (John II does). In other words: John II being born doesn't cause John III to be born.

In per se series w being A causes x to be B, x being B causes y to be C, y being C causes...