Voldemort wanted 7 horcruxes as it was the most magically powerful. But he didn't have 7. With Harry he had 8.

Would Seven of actually been more "powerful". If so, how?

How did not having seven effect them?

 

Well, we don't actually know how powerful magical numbers are in the HP universe. Everything would be speculation.

 

Seven would have been better than eight, but we have no word on the details. The only in text authority to come close to speaking of it found even one too horrific to contemplate.

 

But how would Seven be better? The horcruxes worked perfectly, hard to destroy, didnt randomly fail.

I can’t see how and number would make it better or worse, hell why not 144? The only number that seems better is more.

 

Seven is a magically powerful number. Magically powerful number > average joe number.

Horcruxes working 'perfectly' is debateable. They kept him alive, but he was a few feathers short of a hippogriff. Whether that was a consequence of making one, making so many, or just his charming personality has long been disputed.

 

Back in my early fanfic days, I toyed with the idea that seven would render him not just immortal, but invulnerable as well. Kind of bullshit, looking back, but something that might appeal to him, I suppose.

 

I think it has been heavily implied that the more horcrux you make, the more unstable it renders your soul. So, other than making it a bit harder to kill him I doubt it worked out the way he wanted or would have wanted to.

 

Nah, it's clearly a progressive effect of horcruxes.

Soul was magically relevant since well probably always, and magic is strongly related to religion. The concept of theosis, for example, came to Christianity from the mystical current of Neoplatonism (which was polytheistic in its nature) in which most of pre-Enlightenment western esoteric is rooted. Then you have all the funny shenanigans with the incorrect dating of Hermetical writings. You really could write (and there were written) long texts of relations between western esoterical thought and Christianity. And what could be called eastern esotericism is even more strongly interlocked with religion. A very good example here is Daoism with its internal alchemy and its elements basically being adapted in Japan into a magical system of Onmyoudou.

Dumbledore seems to be quite sure that Voldemort meant seven soul pieces.

 

Seven is more powerful than eight acc to canon. My guess on how this better result might manifest is in the form of luck and chance. With 7 horcrux, little things that could possibly go in horcrux's favor might've done so, like harry being too late to save ginny, or getting caught at gringotts before reaching horcrux. Remember that soul magic is supposedly an esoteric branch of magic and for such branches normal logic doesn't work. Entire branch of divination is based on things happening exactly as prophecised as if being guided by an external power.

 

I don't think there was ever canonical evidence showing how seven was ever better than eight. There was only statements made by Riddle according to his research. Granted, Voldemort probably did a hell of a job researching everything he could about Horcruxes, so seven may well have been better than eight, but there's no hard physical evidence of this fact.

There's also the fact that for some reason Voldemort's soul was so unstable that he unwillingly (and unwittingly) split his soul into 8 pieces during the Potter murders, which kind of leads me to question seven's power. If seven was optimal, why was his soul so unstable that it split apart so easily?

 

I always thought the whole seven being a magically strong number was kind of a superstitious thing, even in canon?

I never even got the sense that a Horcrux even added to his magical prowess, rather it was just a way of making himself immortal.

As very few (If any) people in history had made more than one Horcrux, it seemed that Voldemort was looking into how many he could make, i.e what the upper limit was. One wasn't enough for him, the risk of someone destroying it was too high. He probably would have made more than seven but he most likely did not want to take the risk of his soul splitting too far apart.

 

I dont think anyone thinks they made him more powerful.

 

Easily? He took a killing curse to the face, one of the strongest, vilest and nigh unstoppable curses acc. to canon. It should have vaporized his soul, but instead he survived. I can't see how that seems easy.

 

He survived because he could not die due to his Horcruxes. But nowhere in canon does it say that taking a Killing Curse splits your soul.