These are tow interesting articles from Scientific American which posit the idea that human intelligence is ultimately limited by physics and chemistry. This is certainly true, that these are the fundamental limits… I wonder how close we are to them.
These are questions which CPU and semiconductor makers consider all the time… There are obvious tradeoffs in speed versus depth (i.e. small and fast, versus slower and more powerful), packing density versus noise, and a host of other problems with which to navigate through.
Of course, one you get past this sort of brain- semiconductor equation, the real problems start to come up. For instance is the mind merely an operating system or are there emergent aspects to consciousness which we don’t really understand in play…
Faster, Smaller, Better: Does Physics Put an Upper Limit on Brain Efficiency?
http://www.scientificamerican.com/article.cfm?id=axon-animations-limits-of-intelligence&WT.mc_id=SA_facebook
Just as shrinking transistors makes computers more powerful, brains with smaller components could in principle pack in more power and become faster. The human neuron, however—and in particular, its long “tail,” called an axon—may already be at (or close to) their physical limit.
Axons are the nervous system’s telegraph wires, enabling neurons to form networks. When a neuron fires, it sends an electrical signal down its axon, which then stimulates other neurons. The signal travels down the axon by opening ion channels embedded in the cellular membrane, letting ions pass through. When enough ions cross a channel, they change the voltage across the membrane, which in turn causes the nearby channels to open, propagating the signal in a domino effect.
In principle, our brains could evolve to have thinner axons, which would save space so that more neurons and more axons could pack in. Thinner axons would also consume less energy.
Nature, however, already seems to have made axons nearly as thin as they can be: any thinner and the random opening of the channels would make axons too noisy, meaning that they would deliver too many signals when the neuron was not supposed to fire.
The problem is that ion channels are not precisely controllable. Instead, they open and close at random many times a second. Electrical signals only change the likelihood that they will open. In a typical axon the random opening of an ion channel does not have serious consequences, because the channel closes again before letting in too many ions (first animation).
If evolution made axons much thinner, however, the opening of a single ion channel would often create a spurious signal which then would travel down the axon. Too much of this noise would make the neuron unreliable.
The Limits of Intelligence
http://www.scientificamerican.com/article.cfm?id=the-limits-of-intelligence
Santiago Ramón y Cajal, the Spanish Nobel-winning biologist who mapped the neural anatomy of insects in the decades before World War I, likened the minute circuitry of their vision-processing neurons to an exquisite pocket watch. He likened that of mammals, by comparison, to a hollow-chested grandfather clock. Indeed, it is humbling to think that a honeybee, with its milligram-size brain, can perform tasks such as navigating mazes and landscapes on a par with mammals. A honeybee may be limited by having comparatively few neurons, but it surely seems to squeeze everything it can out of them.
At the other extreme, an elephant, with its five-million-fold larger brain, suffers the inefficiencies of a sprawling Mesopotamian empire. Signals take more than 100 times longer to travel between opposite sides of its brain—and also from its brain to its foot, forcing the beast to rely less on reflexes, to move more slowly, and to squander precious brain resources on planning each step.
