[[Michael Pollan]] [[lit/kindle/How to Change Your Mind|Highlights]] What I appreciate most about Michael Pollan's approach to understanding the power of psychedelics for therapeutic work and personal transformation is his insistence on a materialistic model for the presence of these plants and their effects on humans. I may be more open minded than Pollan, but starting from this point of view is, to me, important. Why? Because a materialistic model is not only most likely (according to Occam's Razor) but also most expedient. The better we understand these medicines from a materialistic point of view, the better we can leverage them in new technologies that can be widely adopted. To Pollan, a reasonable explanation for the presence of psycho-active compounds in plants is the evolutionary benefit of appealing to foraging *homo sapiens*. Like peppers who developed capsaicin as a defense mechanism from predation but hit the evolutionary jackpot when enlightened foragers experienced the compound as a pleasant spiciness, psychoactive compounds may have proliferated due to their importance in nascent human spirituality. But what of the experience itself? What explanation is there for the ineffable experience that is so similar across different users? Pollan divides the book into three sections: first chronically the history of psychedelics in the modern Western era from the discovery of LSD by Albert Hoffman in 1943 through the "renaissance" of therapeutic and scientific uses that he marks began in 2006. Next he includes a "travelogue" where he describes three trips he had on the psychedelics LSD, psilocybin, and 5-MeO-DMT, also called "toad". (In an appendix he briefly discusses a trip on ayahuasca). Finally he discusses the neuroscience of psychedelics and their use to treat death, addiction, and depression. In this final section he presents his argument, based on the latest research, on what may be happening under the effects of psychedelics. The default mode network, the part of the brain that is most active when we are not really doing anything, appears to be suppressed, allowing other functions of the brain to be promoted and also opening up connections that are otherwise moderated by the default mode network. He shares a graphic (originally published by [Petri et. al.](https://royalsocietypublishing.org/doi/10.1098/rsif.2014.0873)) that shows this increase in connectivity.  *Depiction of the connectivity of various brain networks under normal conditions (a) and under the effects of high-dose psilocybin (b). The width of the links is proportional to their weight and the size of the nodes is proportional to their strength. Note that the proportion of heavy links between communities is much higher (and very different) in the psilocybin group, suggesting greater integration.* If we associate the default mode network with what we think of as our ego, then this suppression is akin to an ego death. The default mode network also functions as a reducing valve, ignoring irrelevant stimuli and casting new stimuli in predictable lights. The therapeutic results may stem from the ability of previously suppressed parts of the brain to communicate more directly, without moderation. Many disorders like depression, OCD, anxiety may be the result of an overly active default mode network. Psychedelics bring a new mode of thinking into the forefront, which can have lasting benefits. However, he notes that for most people the benefits will wane over time.