I would call it the difference between the algorithms and the synapses.
“When websites prioritize search over navigation, users must invest cognitive effort to create queries and to deal with the weak implementations of site search. (…) Site search is vital and can save the day for those users who have well defined goals and a good understanding of the information space in which they are searching. However, if you’re considering pushing search on your site at the expense of navigation, think again. Navigation serves important functions: it shows people what they can find on the site, and teaches them about the structure of the search space. Using the navigation categories is often faster and easier for users than generating a good search query. Plus, many times site search does not work well or requires users to have a good understanding of its limitations.”
