To experience a sense, be it touch or hearing, a part of the brain must interpret specific electrical codes. Regardless of the willpower, the brain will subconsciously process this information, and usually without any deceptions.



If you glide your hand over an old trunk of a tree, you will feel its rough pattern. Or if an old song is playing on a FM broadcast, you will undoubtedly hear the memorable tune. And in both cases, the object must be present in order for your senses to be stimulated and to naturally respond to that object. In reality, excluding schizophrenics, drug addicts and any other persons suffering from mental illness, in order to see, hear, smell or touch a certain object, the object must exist and be present. Simply put, it is impossible to taste a tomato while eating a banana. 



However, in a dream, specifically in a lucid dream (when someone dreams consciously), all the senses that respond to a non-existing object in a dream can still be felt by the dreamer as if it actually happened in reality. In simple words, a lucid dreamer can see, smell, touch and taste a tomato without the tomato actually existing! 



If we know that smelling occurs from molecules entering the nostrils, and hearing is made possible because sound vibrations enter our ears, how is it still possible to hear music, taste fruits, and experience all the other senses in our dreams?



Well, the answer is quite simple. Cavallero Cicogna suggests in his report “Cognitive aspects of mental activity during sleep” that the dreaming and waking minds share the same cognitive mechanisms, only on different levels of engagement. He suggests that it isn’t necessary to have a real object to stimulate the senses. The truth is that the brain can recreate sensory impressions and experiences from memory, as stated by Klösch in his paper “Dreams are made up of this”. 



So we now know that our memory can allow us to re-taste that delicious tomato in our dream without actual ‘tomato molecules’ entering our nostrils. 



So how about lucid dreams?



It is said to be scientifically proven that a person who’s consciously dreaming, has more intensive sensory impressions because ones different state of mind. 

In a lucid dream, if you consciously eat a tomato, you expect it to taste like one. The brain then automatically obeys your request and activates specific signals from your memory, allowing you to actually taste the tomato.



So it is safe to say that it is possible, thanks to our magnificent mind, to live an alternative life in our dream based on our senses recreated by our memory. 



Works cited:

Cicogna, P., Cavallero, C., & Bosinelli, M. (1991). Cognitive aspects of mental activity during sleep. American Journal of Psychology, 104, 413–425.

Unlocking the Lucid Dream. By: Voss, Ursula, Scientific American Mind, 15552284, Nov/Dec2011, Vol. 22, Issue 5

SWEET DREAMS ARE MADE OF THIS. By: Klösch, Gerhard, Kraft, Ulrich, Scientific American Mind, 15552284, 2005, Vol. 16, Issue 2