Over the last few decades there has been a miniature industrial revolution in the buying and selling of securities on capital and derivatives markets. Whereas most trading once happened in open outcry pits or over the phone, trading now occurs primarly via electronic limit order books. Whereas once traders could have little education and find work as a consequence of membership in a local insular network, new financial hires are now the most talented graduates of PhD and master’s programs in the hard sciences and mathematics. Even though these circumstances are well attested, knowing is not enough for some to become this new kind of trader. I suggest that the theory of semiotic ideologies—that is, what grounding assumptions people bring to the process of interpreting signs—can be used to illustrate boundary cases of social change in which people are simply unable to learn enough to adapt to new circumstances in their lives. I will show that even though traders can adopt the appropriate semiotic ideology of markets that their times demand, some of them will never be skilled enough to fully participate. This, in turn, has to do with the nature of change in a capitalist economic system.