The Stoic and Drugs

I wonder why anyone who professes the Stoic way of life would want to use any substance that would interfere with the functioning of the brain.  Consider this: our brain, and our sensory apparatus, evolved over millions of years in order to give us an accurate picture of the world around us.  Without this, we do not survive as a species.  Why alter it?

Our brain is, for us, an optimal combination of sensory perception and reasoning ability.   Sure, there are animals that see better than we, who hear better, who smell better.  No argument there.  But, such abilities come at a price.  I was watching a presentation on the Animal Planet; in it the host was talking about a breed of dog--and I forget which one--with an incredibly accurate sense of smell, and it wasn't the bloodhound.  This dog has an amazingly accurate sense of smell, but 50% of his brain is dedicated to smell perception and recognition.  That is a high price to pay for that ability.

Anyone who has owned a bloodhound knows what I mean.  Those amazing animals can track a scent for miles on only a drop of blood, but that ability has left them with a brain that is one of the least capable in the canine world for learning new tasks not related to smelling.  In other words, that dog can track a tiny item for miles--and save lives in the process--but not be able to learn to get off the couch!  That is a trade-off that would have meant elimination for the hominid line.

To refer back to the image of the chariot: the driver must control the chariot and the horses, and it is just as hard to drive a chariot while intoxicated as it is a car.  What is gained?