Billions and Billions
Nobody really knows how many brain cells anybody has, but typical estimates are around 200 billion. You've heard the late Carl Sagan talk about 'billions and billions of stars' in the universe. Think about this. Each brain cell has many connections with many other brain cells, by way of multi-branching dendrites and axons, communicating across a mind-bogglingly large number of synapses.
How many? If each brain cell connected once to each of the others, that would be 4 with 22 zeros after it, a number so large that it would put Sagan and his billions of stars to shame. One well-known researcher has even asserted that a single human brain has more potential connections than the number of atoms in the universe. Is that really true? In mathematical terms, yes. However, since each connection depends on many atoms, there's no way that such a huge potential could be realized, even in theory. But suffice it to say that the human brain has a vast potential for thinking and learning.
