Reflections only exist in our minds.

I'm just going to jump in and begin making clarifications. My opponent begins by discussing how the human eye works, that the images we see are just our brain's way of interpreting light waves that hit our eyes. This is all well and true, however if I am able to show that reflections exist outside of the mind, then I have won this debate. The other side admits that there are certain objects which have objective reality (say, a soccer ball), but maintains that reflections are an optical illusion -- that we are seeing something that does not have an objective reality. His main argument for this is that reflections do not occupy a physical space and that they can't be perceived via our other senses. I'll hit both of these arguments, in the reverse order presented. 1. Reflections cannot be perceived with our other senses. This argument doesn't particularly work when we realize that there are many things which we cannot perceive with our senses, but which we know exists. Consider ultraviolet light, for instance. We currently have no way of detecting UV light with any of our five senses, but science has confirmed that they do indeed exist. This example alone disproves the idea that what cannot be perceived with our naked senses alone does not have objective existence. Furthermore, the fact that we can perceive reflections with our eyes implies that they do have some degree of physical existence. My opponent claims reflections are an optical illusions, but that would imply then that we are still seeing something, it just isn't a reflection. I can't imagine what my opponent would argue we are actually seeing. Perhaps light? But if that is his argument, then we are indeed seeing a reflection. More on this in my next point. 2. Reflections do not occupy physical space. First it is beneficial to define exactly what a reflection is. According to Merriam-Webster, a reflection is the return of light or sound from a surface, or alternatively, the production of an image by a mirror or as if by a mirror. Before analyzing the definition, let's talk about what happens during a reflection. We'll assume light is being reflected. Some object emits/bounces photons which hit a mirror. The mirror does not absorb the photons, so they are reflected away at an angle. For instance, imagine a soccer ball that is being reflected in a mirror. Photons leave the soccer ball, hit the mirror, reflect at an angle, then hit your eyes. Now while a photon does not have mass (and it is unclear whether it occupies space in any meaningful way), it does have the ability to interact with matter that does have definite mass. For instance, when photos hit an object, they apply a (very small) force upon that object. Clearly photons exist because they interact with the world in this important way. If photons are real, then a reflection is simply a bounce back of these photons, implying that the reflection itself is real. As for the definition of reflection, it is quite clear that if there exist a mirror which reflects light, that image created is, by definition, a reflection. I believe my opponent is mistakenly arguing that the image scene isn't the same object as the one reflected. This is true. A reflected image of a soccer ball is not a soccer ball, however it is a reflected image. Both the soccer ball and the image exist, outside of the mind. 3. An argument of my own. Now that we have shown the opponent's thought process to be faulty, I'll present an argument proving that reflections can exist outside the mind. To do this, we must simply eliminate the 'mind' from the situation, then determine whether reflections still exist.Imagine an uninhabited world far off in the universe. It is composed, in some places, as a large, smooth sheet of ice. Beside one particular sheet of ice, there is a mountain. Now if photons are being thrown off the mountain, then hit the ice, then thrown off at an angle, there is indeed a reflection happening. We don't need to observe the situation to understand that physics demands the existence of a reflection. And since this reflection is existing without being observed, it exists outside the mind. I look forward to my opponent's response.