Our thinking proves that we exist.

As our senses can so easily deceive us, we should spend our lives as vigilant skeptics. But what’s there to gain from a life full of doubt? Well, it does give us one thing we can be sure of: the fact that we’re thinking.
There might be an evil genius messing with our senses, but we can challenge our senses and imagination by thinking about them. Regardless of what our senses tell us about the world and our place within it, the one thing we can depend on is that we think. This leads to one conclusion: we think, therefore we exist.
But how can we know we’re really thinking? Well, imagine a piece of beeswax. Freshly made from honeycomb, it smells, feels and looks like beeswax. If we put it close to the fire it melts, yet we still know that it’s a piece of beeswax. How do we recognize it?
Through thinking. Our mind makes judgments and definitions of the world outside, so when our senses can’t be trusted, our mind fills in the gaps. But couldn’t the beeswax be just a dream or a production of our tricked sensory impulses? Maybe, but the fact that our brain perceives it and makes the judgment that it’s beeswax means we are thinking. This way our mind proves that we exist.
Even if we’re just thinking nothing more than “I don’t exist,” the fact that we are thinking it proves we do exist. But if our mind can prove our own existence, what about the existence of other things in the world? Are they real at all? And how can we know?