"Our brains have evolved mainly to deal with our body and its interactions with the world it senses to be around us. Is this world real? This is a venerable philosophical issue and I do not wish to be embroiled in the finely honed squabbles to which it has led. I merely state my own working hypothesis: that there is indeed an outside world, and that it is largely independent of our observing it. We can never fully know this outside world, but we can obtain approximate information about some aspects of its properties by using our senses and our brain."