The Forms I read the first and last pages of this thread and would like to contribute. If any contributor thinks I would learn significantly more by reading some other pages before I post, please just say so. If you choose to do so, please include the relevant pages (even if its all of them) in your recommendation.
I must confess that at times, as I read, I was not sure if I was reading a rebuttal or an agreement. Sometimes the language is fairly obtuse to me. I am familiar with Platonic forms but it has been nearly fifty years since I read Plato and it’s possible I was mistaken about how well I understood it then. Today, I only loosely understand many of the posts here and have considerable uncertainty whether my ideas are relevant or appropriately expressed. If you think my post is not relevant, it’s okay to stop reading at any time and just skip/ignore this post.
In my view the Platonic forms are not dependent on physical manifestation to be real. Their existence is demonstrated/proven mathematically (at least enough for me) as an ideal that we can compare physical objects to. When concepts cannot be understood mathematically, it is difficult for me to consider them real. For example, I cannot prove mathematically or observationally that a teapot is not in orbit around Mars. I require such evidence before I would concede the teapot’s existence. I apply the same principle to string theory and multiple universes. Perhaps some physicist have proven them to their own satisfaction but they have not persuaded me. I am not suggesting that I have to be persuaded of something for it to be real, just that I have to understand the proof or have enough confidence in the claimant to accept the claim.
When Cro-Magnon hunted with spears (perhaps in groups), they understood arc and force enough to kill large animals so they could have lunch. If they failed in their effort they would either go hungry or become lunch themselves. Newton, demonstrated that arc and force could be understood mathematically (Calculus). Even though Co-Magnon did not do Calculus they understood how much force and angle to apply to be successful hunters. I call this Analog Knowledge.
I am of the camp that holds that accomplishments in mathematics are discoveries, not inventions. In other words, the mathematics to understand arc and force existed in Cro-Magnon’s time but was discovered by Newton. In this way, it is the pursuit of the ideal that allows us to calculate the behavior of objects in motion sufficiently enough to visit other bodies in space. In my view, by doing so humanity clearly demonstrated that the ideal was real.