JM:
You've suggested many times that
human cognitive capacities have limitations; they must have, because they're biologically based. You've also suggested that one could investigate those limitations
.
NC:
in principle.
JM:
. . . in principle. Unlike Kant, you're not going to simply exclude that kind of study. He seems to have thought that it's beyond the capacity of human beings to define the limits . . .
NC:
. . . well, it might be beyond a human capacity; but that's just another empirical statement about limitations, like the statement that I can't see ultraviolet light, that it's beyond my capacity.
JM:
OK; but is the investigation of our cognitive limitations in effect an investigation of the concepts that we have?
NC:
Well, it may be contradictory, but I don't see any internal contradiction in the idea that we can investigate the nature of our
science-forming capacities and discover something about their scope and limits. There's no internal contradiction in that program; whether we can carry it out or not is another question.
JM:
And common sense has its limitations too
.
NC:
Unless we're angels. Either we're angels or we're
organic creatures. If we're organic creatures, every capacity is going to have its scope and limits. That's the nature of the organic world. You ask “Can we ever find the truth in science?” – well, we've run into this question. Peirce, for example, thought that truth is just the limit that science reaches. That's not a good definition of truth. If our cognitive capacities are organic entities, which I take for granted they are, there is some limit they'll reach; but we have no confidence that that's the truth about the world. It may be a part of the truth; but maybe some Martian with different cognitive capacities is laughing at us and asking why we're going off in this false direction all the time. And the Martian might be right.
JM:
. . . assuming that the Martian could understand our cognitive capacities
.
NC:
. . . right.
JM:
The project of investigating the limits of our cognitive capacities seems to me to be quite different from the kinds of projects that philosophers are fond of, or have been fond of, when they have introduced various kinds of epistemic constraints on what counts as meaningful or sensible or whatnot. Investigating the limits is a scientific project, not what too often amounts to a stipulative one
.
NC:
My own interpretation of those proposals is that they're suggestions about our
science-forming capacities. So these epistemic limits . . . your proposals should be consistent, try to avoid redundancy, try to unify different aspects of science – physical reductionism, say – I think that all of those can only be understood as explorations of the way that we, as particular creatures, try to proceed to gain our best understanding of the world in a systematic fashion. That's the way we do it . . . But if you want a proof that it's the
right
way, well, I don't see how that can be possible. All you can say is that it's the best that we can do. We may discover that we're always going off track, in which case maybe that's irremediable. If we can't find a different track, it's irremediable. And sometimes – if you look at history – humans have found a different track by lowering their sights. So, for example, lowering one's sights from understanding the world to understanding theories about the world led to a rather significant change, and it's a change – it's sort of symbolized by
Newton – that took several centuries to become internalized.
JM:
It gives you a very interesting understanding of
Wittgenstein's
Tractatus
and a number of other works in that genre. Was
Russell engaged on that sort of project, at least as you understand him – in his early work?
NC:
Pre-
Tractatus
?
JM:
Russell before [Wittgenstein's]
Tractatus.
NC:
He was engaged in a kind of conceptual analysis that I think he regarded as giving us insight into the nature of reality. But it was conceptual analysis – as, for example, the theory of
descriptions.
JM:
By the time of
Human Knowledge: Its Scope and Limits,
he was quite explicit about making proposals, based on an understanding of human nature
.
NC:
There it is explicit. It becomes a much more subtle and sophisticated approach that does appear to recognize – as the very title of the book indicates – that we're dealing with some organic phenomenon that is going to have its
scopes and limits. He doesn't quite say it like that, but I don't know any other way of reading it.
JM:
You do get normative overtones in a lot of philosophical writing – this is the way you
ought
to proceed . . .
NC:
There's nothing wrong with that: you ought to do it by our lights, by the way we see things. It's the same with moral judgments.
JM:
How does that differ from saying, “this is the way we
have
to do it?”
NC:
It would be “this is the way we have to do it” if we knew enough about ourselves to say that there aren't any choices. Like “I have to fall off a cliff if I jump; I can't help it.” But we don't have that kind of understanding of much more complex things, like great areas of our lives.
These kinds of questions come up in
naturalistic moral theories and naturalistic epistemological theories, and in both – which are the traditional ones – you can try to work out what our moral instincts are and what our moral faculties are. But there's a gap between that and what's objectively right – an unbridgeable gap from the standpoint of some non-human creature that can be understood to be right, something of which our moral nature has only a partial grasp.
And the same is true of epistemology. What makes the best theory? People use the term “
best theory” freely, but what is the best theory? Well, we can try to sharpen up our criteria, as we understand them, but we're doing something analogous to investigating our own moral nature. We're investigating our epistemological nature, and within that framework you can come up with some notion of best theory that is on a par with our notion of right behavior. But again, from some point of view or standpoint that is external to us – which we can't take, because we're us, not that external thing – it could be evaluated in quite different ways.
JM:
You're not assuming that we can make sense of the notion of an objective right or an
objective truth?
NC:
I do believe that there is an objective truth; ok, so I'm a naïve realist of sorts – I can't help it. But I think that if we think about ourselves, we will see that there is no way to have any confidence about it. We can have confidence about the fact that this is the best I can do with my cognitive capacities – and we can have less confidence, because we understand less, that this is the right way to behave in accordance with our moral nature. And I presume that we all have the same cognitive capacities and moral nature. But – and here we get to the last line of the
Tractatus
[of Wittgenstein] – beyond this, we just have to keep silent.
JM:
But there are people such as
Peirce who tried to give some kind of content to the notion that there is an objective truth. Whatever an ideal science happens to discover . . .
NC:
He was putting it in the framework of an extremely poor
evolutionary argument. It was a fallacious argument. If you take that argument away, then the conclusion collapses. His argument was that we were selected to attain the truth. We wouldn't have survived if we didn't have a truth-seeking capacity, and therefore if we just pursue it to the end, we would have the truth. That's the core of the argument. But it just doesn't work. Nothing in human evolution selected people who were good at quantum theory . . .
JM:
If one believed that the mind were – counterfactually – something like a universal device, that we have some kind of capacity to be able to solve every problem we might encounter . . .
NC:
. . . and to pose any kind of question . . .
JM:
. . . and to pose any kind of question . . .
NC:
I just don't know what that would mean. That's no organic entity that we can even conceive of.
JM:
Still, a person who held that kind of belief might have a different kind of view about human
cognitive capacities and objective truth . . .
NC:
A person who held such a belief would be saying that we are somehow angels. There couldn't be a creature in the universe that would incorporate our cognitive capacities as a sub-part, maybe reject them the way we reject commonsense contact mechanics, and maybe go on to ask further questions that we don't know how to pose, and maybe find answers to those questions, without limit. How can we say that? How do we go beyond the limits of possible organic development?
JM:
When you speak of investigating the limits of our cognitive capacities, I assume that you are allowing that there might be cognitive capacities that we simply have not been able to . . .
NC:
. . . have not produced thus far. Yes; that's not at all surprising. Take, say, your arithmetical capacity. That wasn't used throughout almost all of human evolutionary history. There's just a tiny little fleck of time during which that capacity has ever been used. This is what bothered
Anthony Wallace in his debates with Darwin. He argued that things like a mathematical
capacity couldn't have been selected, because they were never used. If you don't use it, it can't be selected. But they've got to be in there somehow. And, he suggested, there must be some other forces like gravitation, chemical
reaction, and so on that entered into the development of what he called human moral and intellectual capacities. That was regarded at the time as a kind of mysticism. But we should regard it as just sane science. It's on a par with what Newton was unable to accept, but should have: there are forces in nature that are beyond interaction through contact. Newton said it [there are such forces – specifically, gravity], but he didn't believe it. But it was right.
JM:
If one had a view of
human biology or perhaps biology in general rather more like Turing's or D'Arcy Thompson's, then you'd want to allow that proving useful is not a condition of a biological entity having some structure or being some kind of thing
.
NC:
Take D'Arcy Thompson. If biophysical laws determine the general shape of the properties of creatures, it doesn't say that you can't build
submarines.