Try telling Ray Comfort that

He won’t get it, because like a heck of a lot of people, he doesn’t understand systematics at all. We will continue to try, though. Here’s a simple introduction to a basic concept in cladistic taxonomy:

One of the central tenets of modern taxonomy is that every group has to include, by definition, all of the groups that evolve from it. So rats did not stop being mammals when the rodent group branched off the evolutionary tree. Every branch on the tree of life is considered to be a member of all its parent branches.

This means, for example, there can be no definition of fish that does not include everything that evolved from fish. Following this logic you could argue that as amphibians evolved from fish, amphibians are fish. Mammals evolved from animals that evolved from amphibians, so mammals are fish. We are fish. While every biologist knows this conundrum, and that there is no biological definition for what most people consider “fish”, they decide not to worry about it because it’s helpful to think about living swimming “fish” as a group. Taxonomy is useful and makes a lot of sense, until it doesn’t.

There are other ways to classify organisms — we could do it by what color they are, or what they eat — but the one method that works coherently is to group them by line of descent.


  1. birgerjohansson says

    Aristotle called humans “featherless bipeds”. He got mocked by a philosopher who provided a plucked chicken, shouting “behold Aristotle’s human”!
    — — — —
    In the first Alien film, the victims were supposed to metamorphose into Alien eggs, but that was cut. Imagine what kind of crazy evolutionary ideas Ray Comfort might have had from watching that.
    — — —
    Are there no mammals in our lineage who hibernated? It would be useful to re-activate any dormant genes for that ability.
    BTW did primates diverge before or after the K/T boundary? Anybody here who knows about the latest genetic “clock” research?

  2. Ichthyic says

    don’t try telling Ray anything.

    when you see him?

    pretend you want a selfie and lick the side of his face instead.

    there’s a reason, trust me.

  3. slithey tove (twas brillig (stevem)) says

    Common line in movies, “That whale is a mammal . NOT a fish”
    There is value in specificity rather than generalist ? IMO

  4. latveriandiplomat says

    Don’t tell Ray about set theory. “Sets nested inside other sets? That’s crazy talk!”

    There’s a lot of confusion to be had by trying to group sharks, coelacanths, and say perch in one group, not to mention traditional uses of the “clear” word fish that threw in things like starfish and whales.

  5. Mark Dowd says

    The amusing upshot of this is that, since “fish” is paraphylitic and based on an arbitrary assortment of physical characteristics rather than unambiguous evolutionary relationships, you have a weapon to 1-up the next smarter-than-thou pedant that insists that whales and dolphins are not fish.

  6. slithey tove (twas brillig (stevem)) says

    gosh I see the easy , uhhh ~confusion~ twixt whales and fish. First speaker focuses on one aspect, “lives in water”, while the second speaker focuses on a distinguishing aspect “breathes air not water”. Neither are rigorous. Neither of the two are being pedantic (formally), just casually nit-picky.
    or trying to play one-upsmanship (is that a word?)
    shick, looks like I’m digging a hole… “fish” is “ghoti” [trying to derail the derail]

  7. whheydt says

    Hence the title of Neil Shubin’s book…_Your Inner Fish. (Everybody *here* has read it….right?)

  8. monad says

    There could easily be definitions of fish that exclude tetrapods. It would just mean fish aren’t a taxon, but an ecological category. Those aren’t useful for classification but can still be useful to have in your language, especially since we already have an equivalent taxon, Craniata.

  9. says

    Comfort’s argument against evolution is on the same side as Virginia’s against Loving, with the same mentality. It’s an argument from ignorance to justify a belief and a prejudice.

  10. Crip Dyke, Right Reverend Feminist FuckToy of Death & Her Handmaiden says

    But, but, but …

    Ray Comfort came from Jesus and Jesus is a fish, right?

  11. militantagnostic says

    Crip Dyke @12

    Ray Comfort came from Jesus and Jesus is a fish, right?

    I think of Ray Comfort as more of a loaf than a fish.