Sometimes it looks like a wave and sometimes it acts like a particle because empty space is a fluid made up of particles called the higgs field.
Science is a language. In this language, it can be either one, depending on the most practice way of describing it. Consider chemistry: it only talks in terms of heat. For it, coldness doesn't exist. Now, clearly coldness exists, but not in chemistry, only heat, because heat is easier to talk about or measure. Likewise, whatever way is easier to describe light, physics will use. The only other way to think of it, I would call it's existential sense. But light as it appears to us is neither wave, nor particle, just warmth and brightness.