So I've been wondering for a while what's going on, exactly, with Flowey, because something about him just doesn't add up at all. We know that robots are made of metal and magic, but what is Flowey made of? The part that I feel most opposed to is the claim that Flowey does not have a soul. This is a fairly typical stance because Flowey is kind of a jerk, and is commonly said to be emotionless, and because Alphys said so. The first part is irrelevant, the second is incorrect (Flowey does feel emotions, just not positive ones; he frequently expresses fear, frustration, and lots of anger), and the last part… well, if you've gotten this far and trust everything Alphys says… you're doin' it wrong. Besides, how COULD she know? She didn't even know that the flower she chose was the one dusted by Asriel's ashes. She thought it was just another flower and picked it at random. She just assumed that it didn't have a soul because flowers typically don't.
Either way, it doesn't make sense that a mere flower could suddenly gain sentience simply from Determination. Determination is a power source, not a mind or soul. It wouldn't make it move. As someone else pointed out in another thread, how could a soulless being that's not a monster even be able to use magic attacks in the first place? Monsters are made mostly of magic so their souls are better attuned to it. Their souls essentially are their bodies, and thus are their magic. This is why their bodies and attacks weaken when their souls lose the will to fight. If Flowey had no soul, and no monster body, where could his attacks come from? There wouldn't be any magic to use.
But the most important reason why I can't accept the soulless-Flowey hypothesis is because it would mean the child you encounter at the end of the game WOULD NOT BE ASRIEL! It would be just something like a copy, clone, or echo of him given some weird agency and somehow pulling his memories from the aether.
It's said that the "Boss Monsters" have souls that can persist for a moment after death, something that doesn't happen with other monsters. Considering that they're the defacto rulers of the Underground, this might just have something to do with a kind of innate strength or power. The more powerful the monster, the longer the Post too long. Click here to view the full text.