These ‘Part b’ things seem to be a recurring feature, so I’ll make a formal declaration about what they are now. Part A will be a discussion of the book and the major themes that arise. Part B will be an application of a theme, even if it is not one of the major themes from Part A. As such, this one will be about the claim that a thing is the thing you want to use it as, or ― at least ― what you want to use it as defines its parameters.
This is reminiscent of the discussion in Beginning of Infinity by Deutsch; that we have to apply a creative interpretation of what we see to make distinct objects out of them. In turn, this is reflective of Buddhist thinking that objects have no definite borders.
There are two senses in which this works. A table, for example: it is only a table because you intend to use it as a table. There’s no definitive definition: in the right place, a large tree stump is a table; a coffee table might not have 4 legs, etc. Short of imagining using it as a table, how should we draw the lines around it, in space or time? Without reference to its valence ― how you imagine using it ― it is no more a table than just a post-tree object, or just another part of the hydrogen/time/gravity evolving system. A tree stump that you use as a table doesn’t consider its roots, but without your interest in using it, the stump cannot be conceptually separated from its roots, and its roots are only an object separate from the soil because you understand their distinct function. The same is true inwards: you treat the stump as a whole, but it is no more that whole that it is separated into bark and buttress, phloem, sap wood, heart wood…
With people it is a bit more complex, because it allows Peterson to bring Gods back into the mix. For example, a person can be scary ― and thus of a God of Nature or Destruction or other “feminine” wiles ― or attractive ― and thus of a God of sex or love. They are not scary or attractive in some definite way, but by fact of how you perceive them; their valence to you: a thing to be cautious of or run away from, or to seduce.
And this brings us to gender more generally. (It will later bring us to Oat Milk…) There is an irony that Peterson shot to prominence in his objection to the Canadian State creating sanctioned language around gender, specifically he objected to the idea that misgendering someone should be considered a hate crime. It is worth giving Peterson his dues: as far as I can tell, he would use a person’s preferred pronoun. There’s nothing wrong with this: you can object to a government making it the law that you must say “Good morning” to someone who says it to you, and still have that as your habit.
Given the constructed nature of gender roles ― femininity and masculinity ― in Peterson’s book (progenitor, creator, destroyer, monster; ruler, figurehead, tyrant) it makes perfect sense that a person can see themselves and carry themselves in a way that completely violates the received idea of a relationship between sex and gender. And when that happens, that person is the gender they embody. And gender is tied up with sexuality, which is a defining part of a person’s valence (although, not solely). If you are feminine, you are female; if you refuse the dichotomy, you might associate with another gender or none at all. And you are that valence.
On a less controversial footing ― which may make it clearer, as there’s no illusion of political divide clouding the issue ― Oat Milk. In the EU, referring to vegan milk replacements as milk has been banned. They are taking the technical definition of “milk” as a product of lactation. (We’ll ignore, for a moment, that coconut milk has had that name since about 1200AD, and that meat-eaters can enjoy “hot dogs” and “chicken drumsticks”, or that there doesn’t seem to be any confusion over what peanut butter is…)
But, if a thing is its affective valence, then a creamy liquid to add to cereal or coffee or to be used in baking is a milk. A processed tube of mushrooms and beetroot intended to be grilled and put in a bread roll is a sausage.