> [!summary] Progressive Summary # Structured Notes ## Definitions ## Chapter Summaries Cuttlefish, squid, octopuses and nautiluses belong to a group called *cephalopods*. > Through much of the twentieth century, a sensory-motor view of the evolution of nervous systems was simply assumed, and it took some time for the second view, the one based on internal coordination, to become clear. Chris Pantin, an English biologist, developed the second view in the 1950s and it has been revived recently by Fred Keijzer, a philosopher. # Quotes > The demand for continuity has, over large tracts of science, proved itself to possess true prophetic power. We ought therefore ourselves sincerely to try every possible mode of conceiving the dawn of consciousness so that it may not appear equivalent to the irruption into the universe of a new nature, non-existent until then. > – William James, The Principles of Psychology, 1890 > Cephalopods are an island of mental complexity in the sea of invertebrate animals. Because our most recent common ancestor was so simple and lies so far back, cephalopods are an independent experiment in the evolution of large brains and complex behavior. If we can make contact with cephalopods as sentient beings, it is not because of a shared history, not because of kinship, but because evolution built minds twice over. This is probably the closest we will come to meeting an intelligent alien. > ... the sea is the original home of the mind, or at least of its first faint forms. > Doing philosophy is largely a matter of trying to put things together, trying to get the pieces of very large puzzles to make some sense. Good philosophy is opportunistic; it uses whatever information and whatever tools look useful. --- > The receptors on the surfaces of bacterial cells are sensitive to many things, and these include chemicals that bacteria themselves tend to excrete for various reasons—sometimes just as overflow of metabolic processes. This may not sound like much, but it opens an important door. Once the same chemicals are being sensed and produced, there is the possibility of coordination between cells. We have reached the birth of social behavior. > The chemistry of life is an aquatic chemistry. We can get by on land only by carrying a huge amount of salt water around with us. And many of the evolutionary moves made at these early stages—those giving birth to sensing, behavior, and coordination—would have depended on the sea’s free movement of chemicals. > Sensing and signaling between organisms gives rise to sensing and signaling within an organism. A cell’s means for sensing the external environment become a means to sense what other cells within the same organism are up to, and what they might be saying. # References