What I perceive from my direct experience is all going on in my head, and this must be true for other people. So there is no objective reality - just different versions of it. We see it differently in terms of its survival value for us. What we actually perceive is only a very small part of what is actually perceivable anyway. And even that is conditioned by our knowledge, life experiences and other factors. When I look at the boats in the marina where I live I tend to see colours and reflections. An experienced sailor would see a very different picture. They would notice all sorts of details of the boats that mean nothing to me.