philosophers recognize that there are any number of beliefs which we cannot prove to be true but nevertheless which we all accept and are rational in doing so because they're rooted in our experience examples would be the reality of the external world or the reality of the past when you think about it you can't prove either of those beliefs there's no way to prove that you're not a brain-in-a-vat of chemicals wired up with electrodes being stimulated by some mad scientist to think that you're here in this room seeing these objects that aren't really there there's no way to know that the world wasn't created five minutes ago with built in appearance of aged memory traces in our brains from events that never happened food in our stomachs from the meals we never really ate so that you cannot prove evidentially the reality of the external world or the reality of the past and yet these are clearly rational beliefs which we all have you would be crazy literally if you thought that the world was created five minutes ago or that you were a brain-in-a-vat philosophers call these properly basic beliefs they are part of the foundations of a person's system of knowledge but these beliefs aren't arbitrary they're grounded in our experience in the context of seeing and hearing and touching things I form naturally the belief that there is an external world of physical objects which are real and I am rational in holding to these beliefs in the absence of any reason to think that they are unreliable unless the skeptic can give me some good reason to think that I'm a brain-in-a-vat or that these beliefs are otherwise unreliable I'm perfectly within my rational rights to retain those beliefs now I would similarly argue that belief in God is properly basic for those who genuinely know God they have an immediate experience of God as an objective reality bearing witness with their spirit that they are in relationship with him that they know him and that in the absence of some defeat or some reason to think that that experience is delusional you are perfectly within your rights to go with that experience and to believe that that experience is what we would say is veridical that is to say is of an objective reality