The Descartes we met in the first section is a methodologist of science with a bad idea about how to improve our scientific success rate. He isn't so very far removed, then, from the Second Philosopher in terms of his general intellectual concerns. She can warmly approve of this Descartes's overall aim of doing science better: she just rejects his failed attempt at securing that aim.
But there's another Descartes (a fictional figure perhaps, but occupying a familiar location on the philosophical landscape). To quote Stroud,
By the end of his First Meditation, [this] Descartes finds that he has no good reason to believe anything about the world around him and therefore that he can know nothing of the external world.For this Descartes -- or better, for the 'neo-Cartesian sceptic' -- doubt has become more-than-merely methodological. He is not just setting aside received but fallible beliefs about the world, reasonable and unreasonable alike, to locate an indubitable residue: he thinks he has an argument that even the most 'reasonable' received beliefs in fact just aren't reasonable. How does the naturalistically inclined philosopher respond?
Now, speaking for myself, I'm all for a cheerfully resolute response. We have every good reason to suppose that in ordinary life, when our usual criteria indicate that we are wide awake and not dreaming, we are wide awake and not dreaming. And if the sceptic asks me how I rule out the possibility that, for all that, my whole ordinary life is in fact just one big coherent dream (unlike any ordinary dream, of course, a put-up job engineered by an evil demon), I just riposte that I have been given not the slightest reason that to suppose that that is a live possibility. It is one thing to use the evil demon fantasy as Maddy's Descartes does, as an imaginative tool in trying to locate some core of infallible beliefs: it is something else entirely to imagine that the honest enquirer needs to rule out the evil demon scenario before he can regard science as a reasonable enterprise. The scientist just doesn't have to waste her time ruling out myriads of daft hypotheses she hasn't the slightest reason to suppose are true. And for me, pretty much end of story.
Speaking for her Second Philosopher, Maddy is rather more patient in tangling with the neo-Cartesian sceptic (though whether the sceptic will appreciate her efforts is a moot question). I won't go into all the ins and outs. She agrees, of course, that "she can’t justify anything without appeal to her familiar beliefs and methods", but so what? Ah, says Stroud,
... in philosophy we want to understand how any knowledge of an independent world is gained on any of the occasions on which knowledge of the world is gained through sense-perception. So, unlike ... everyday cases, when we understand the particular case in the way we must understand it for philosophical purposes, we cannot appeal to some piece of knowledge we think we have already got about an independent world. [My emphasis]So now, as Maddy puts it, "it's freely admitted that the skeptic is engaged in a peculiarly philosophical project, distinct from mundane concerns". But what notion of 'philosophy' is in play here? I for one just haven't much grip on what sort of coherent project might be meant here, this special 'philosophical' enquiry that isn't part of science broadly conceived. Maddy offers the following from Stroud:
All of my knowledge of the external world is supposed to have been brought into question in one fell swoop ... I am to focus on my relation to the whole body of beliefs which I take to be knowledge of the external world and to ask, from 'outside' as it were ... whether and how I know it ...But that gives the game away. If the 'philosophical' project is supposed to involve jumping outside my beliefs and methods, and trying to squint sideways at them from 'outside' as it were, to see how they match up to an external world, then that is just incoherent. (If the sceptic is complaining that the project can't be pulled off, then he's quite right the project is impossible, but quite wrong to complain.)
Maddy puts it this way,
Our Second Philosopher freely acknowledges one poignant aspect of the human condition: we can't step outside our system of beliefs and methods and justify them from an external perspective; the only perspective we can occupy is our own.But why is that particularly 'poignant'? -- (dictionary: 'evoking a keen sense of sadness or regret'). You can't have a settled feeling of regret that you can't be both 'inside' and 'outside' your own thoughts (thinking them, but squinting at them sideways too) any more than you can sensibly regret that two and two isn't five, or regret that you can't back and kill your own grandfather before he sired your parent. Stroud himself talks of
the desire to get outside that knowledge and that condition, as it were, while somehow retaining all the resources needed to see them as they are.But again, that is just an incoherent aspiration. And if it is a persistent aspiration, then that just means that it's a bit of intellectual bindweed, and the Second Philosopher shouldn't feel any sadness or regret about resolutely taking the flame-thrower to it.