“What if real life is actually a dream?” is a favorite question of Modern philosophers and teenagers who want to sound deep. It’s a curious thought experiment, but in reality we can all easily tell the difference between reality and a dream. But how? The answer is, I think, very simple, but also telling.
Thought experiments aside, we can tell reality from a dream because—to put it a little abstractly—reality contains so much more information than a dream does. Anything we care to focus on contains a wealth of detail which is immediately apparent to us. Whether it’s the threads in a blanket or the dust in the corner of the room or just the bumps in the paint on the drywall, reality has an inexhaustible amount of complexity and detail to it.
Dreams, by contrast, are very simple things. They feel real only because we’re so caught up in the plot of our dream that we’re not paying enough attention to ask ourselves the simple question, “is this a dream?” But if you pay attention, dreams have almost no detail in them; the things in the dream only have properties where one is paying attention. This is also why they have a “dreamlike” quality to them—if we turn away then come back, they may not be the same because they stopped existing while we weren’t looking at them.
And here we come to the fitting part: the difference in richness between reality and dreams shows what inadequate Gods we are. Our creations are insubstantial, inconsistent wisps. We can tell reality from a dream at a glance between it only takes one glance at reality to know that we couldn’t have created what we’re looking at.
UPDATE: I’ve rewritten and expanded this post in a way that makes its point clearer: Telling Reality From a Dream