Necessity and Natural Species Kinds
There are some natural species kinds. for example, Tiger is a natural species kind and Kangaroo is a natural species kind. We tend to make certain claims about these species. For example, we say that Tigers are striped. Whatever the literal content of this claim, it seems we are trying to convey that the species tiger has a certain property related to being striped. For simplicity, let's restate this conveyed truth as one that is explicitly about the species tiger. We can introduce a new predicate, 'striped*' to be whatever property the species has in virtue of which it is acceptable to say that tigers are striped. Now we can explicitly say that the species tiger is striped*. One thing to point out is that it is sometimes acceptable (though perhaps not true) to say that Tigers are striped even though some tiger is not striped. Similarly, it may be true that the species tiger is striped* even though some tigers are not striped (no '*' intended). Now, I am wondering whether it is necessary that the species tiger is striped*.
Here is an argument against that position. Tigers have a certain genetic makeup. Tigers have genes G. We can introduce the new predicate 'has genes G*' to express the property that the species has in virtue of which it is acceptable to say that Tigers have genes G. So, the species tiger has genes G*. But, tigers don't all have the same genetic makeup. There is always genetic variation within a species. Indeed, although the species tiger has genes G*, it seems like there may well be a tiger that lacks genes G* in virtue of having a very slightly different genetic makeup. If more tigers had been like that particular tiger, then it would not have been true that the species tiger has genes G*. The species tiger is susceptible to small variations in genetic makeup*. Moreover, this will be true across some set of possibilities. But, small changes add up to big ones and given that what is possibly possible is itself possible, it follows that the species tiger might have had a genetic* makeup significantly different than G*. In fact, that genetic makeup* might ground the truth that the species tiger is not striped*. Hence, it might be acceptable to say that Tigers are striped, but tigers might not have been striped.
Some of you might recognize that this is related to the Salmon's argument against S5. Of course, there are various responses to that argument and those responses would probably carry over to this argument as well. But I wanted to point out one thing that might follow if we accept the argument I have just presented. It seems that we can have small genetic variations that add up to drastically differences. If that is right and we accept the kind of argument that I just presented above, then it might follow that the species tiger could have been just like the way that the species kangaroo actual is. Moreover, If the species tiger could have been like the way the species kangaroo actually is, then a particular tiger could have been just like a kangaroo. But, if it could have been just like a kangaroo, then it could also have been a kangaroo. Hence, tigers are not essentially tigers. I know this argument goes pretty quickly, but it seems rather interesting to me.
Here is an argument against that position. Tigers have a certain genetic makeup. Tigers have genes G. We can introduce the new predicate 'has genes G*' to express the property that the species has in virtue of which it is acceptable to say that Tigers have genes G. So, the species tiger has genes G*. But, tigers don't all have the same genetic makeup. There is always genetic variation within a species. Indeed, although the species tiger has genes G*, it seems like there may well be a tiger that lacks genes G* in virtue of having a very slightly different genetic makeup. If more tigers had been like that particular tiger, then it would not have been true that the species tiger has genes G*. The species tiger is susceptible to small variations in genetic makeup*. Moreover, this will be true across some set of possibilities. But, small changes add up to big ones and given that what is possibly possible is itself possible, it follows that the species tiger might have had a genetic* makeup significantly different than G*. In fact, that genetic makeup* might ground the truth that the species tiger is not striped*. Hence, it might be acceptable to say that Tigers are striped, but tigers might not have been striped.
Some of you might recognize that this is related to the Salmon's argument against S5. Of course, there are various responses to that argument and those responses would probably carry over to this argument as well. But I wanted to point out one thing that might follow if we accept the argument I have just presented. It seems that we can have small genetic variations that add up to drastically differences. If that is right and we accept the kind of argument that I just presented above, then it might follow that the species tiger could have been just like the way that the species kangaroo actual is. Moreover, If the species tiger could have been like the way the species kangaroo actually is, then a particular tiger could have been just like a kangaroo. But, if it could have been just like a kangaroo, then it could also have been a kangaroo. Hence, tigers are not essentially tigers. I know this argument goes pretty quickly, but it seems rather interesting to me.
posted by Joshua at 11:37 AM
2 Comments:
Does it make a difference here if you're hooking up species-hood to some special sorities-susceptible property as opposed to thinking that species are individuals of a certain sort? What I have in mind here is that we presumably would not want to accept anything like the analogous argument for the conclusion that I could have been you.
I think it might make a difference. I was thinking of the species tiger as some kind of property and it is cross world sorities susceptible in its higher order properties (those ones with *).
I do think these arguments have certain limits. I believe that there is a plausible version of Salmon style argument that shows that I could have been just like you (though not identical to you) but there is no plausible version that shows that I could have been the number 2.
Similarly, the argument I present in the text seems to show that the species tiger could have been just like the species kangaroo. But I don't think there is a plausible argument for the conclusion that the species tiger is the species kangaroo or that the species tiger is just like you.
I do think there is some kind of slippery thing going on in the argument, but I'm not exactly sure what it is.
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