What is so interesting about this text is the way that Pollan looks at botany from a completely different and unique viewpoint, arguing that plants actually have been using humans and our desire for their own purposes in order to help them propogate. The way he explores the complex interaction of human desire with the evolution of plants--in this text he focuses on four (the apple, potato, marijuana and the tulip)--suggests very strongly that these plants have benefited from human desire and have maximised their chances of propogation by adapting to make themselves more desirable to humans. Note how Pollan raises this issue in the book:
They are four of the most common plants we know. We've always thought that WE controlled THEM. But what if, in fact, THEY had been shaping US?
Pollan goes on to argue that this has been precisely the case for the four plants he mentions, citing the way in which the tulip in particular is an example of a plant that has been "reinvented every century or so to reflect our shifting ideals of beauty." Pollan thus argues very strongly that we are defined by what we consume (not just referring to what we eat, but what we smoke and what we purchase because we consider it to be beautiful) and it is our desires that define us as human beings. It is this that has allowed the four plants, and others, presumably, to capitalise on human desire and effectively use us for their own good.
Clearly there are a number of arguments to be considered opposing such a view. One of the worrying and rather disturbing consequences of such an argument as Pollan's is that it presents sentient nature as being cleverer than human intellect. The way in which Pollan argues plants have effectively outwitted humans by making us think that we are using them, whereas all the time they have been using us, calls us to radically reassess our understanding of nature and man's place within it. This is one strong argument against Pollan's view, as humans with their intellect surely have shown through the centuries that it is they who shape the environment around them rather than the other way around. Also, another argument that could be considered against Pollan's view is the way in which humans are infinitely adaptable, and have shown that they are not dependent on any one particular food source. Pollan's argument assumes that there is a dependence between particular plants and humans that is arguably not supported by human history and how we have adapted to fit different circumstances.