"Philosophical autobiographies do much more than simply reveal the personalities and prejudices of their authors, however. They provide striking examples of just why such factors inevitably colour our thinking beyond the biographical."

“The rehabilitation of reason is urgent because it is only through the proper use of reason that we can find our way out of the quagmires in which many big issues of our time have become stuck. Without a clear sense of what it means for one point of view to be more reasonable than another, it seems that the position one adopts is ultimately based on nothing more than personal opinion or preference.”

“This point is, in essence, the most important and overlooked one regarding the rationality of ethics. The traditional dispute between Kantians and sentimentalists rests on an assumption that to be rational, morality must be grounded on a priori principles of disinterested reason. This is false. If we understand what rationality means in an appropriately catholic way, we see that it it is a matter of providing reasons for belief and that the sources of these reasons are not confined to a priori principles of logical or scientific facts. Once we accept that, we can see that although the Kantian project of founding ethics on pure reason is doomed, reason is still at the very heart of morality.”

“There is an irony here. On the one hand, all of these mistakes point to hubris, a belief that human reason is more powerful than it really is. But on the other, all these mistakes implicitly acknowledge how limited the power of reason is, because they require us to simplify our conception of the world in order to make it tractable to reason. It is as though in order to preserve the illusion that human reason is mighty, we have to rig its challenges to make them easier to overcome.”

“When you have strong desires to believe something, it is always possible to convince yourself that a decisive argument against one node wasn’t decisive after all, or that you have found a reply to it. Mending and making do can enable one to think a web of belief still holds together, even after a good critic has ripped it to shreds. But the fact that we know reason will not convince everyone is beside the point. Whether an argument is sound or whether it is persuasive are two different questions. It should come as no surprise that good rational arguments often fail to persuade people. The case for reason is not that it is always psychologically efficacious but that it genuinely helps us towards the truth. However, just as you can lead a horse to water but you cannot make it drink, so you can lead a mind to reason but you cannot make it think.”

“Think of any serious participant in intellectual life. Is there any who does not try to be as comprehensible as is possible? Many are so incomprehensible that we doubt them, but this is almost always a failure of execution, not a success born of intent. Does anyone assert that it is not possible for anyone else to assess the merits of their claims? Very few, and the whole raison d’être of publishing and discussion is precisely that others are, in principle, capable of assessing what they have read or heard and sharing these assessments. Does anyone declare that what they have to say is wholly relative to the interests only of a particular sector of society? Surely not. Even as we acknowledge our biases and partial perspectives, we strive to overcome them as much as is possible. Does anyone think there is no way they could possibly be wrong about what they believe? We may sometimes feel this, but the fact that we nonetheless leave ourselves open to criticism and take those criticisms seriously shows we are committed to the idea that rational inquiry demands we treat our beliefs as defeasible. And finally, when you have seen someone provide what seem to you good reasons for their accepting their position, is your agreement not in some sense involuntary? Similarly, can you not help but dismiss arguments that seem to you weak or ill-founded?”

“Even if we are pessimistic about the chances of changing our political culture to make it more reasoned, we have little choice but to try. In politics, the waters beneath the thin ice of reason are especially rough and icy. The predators that swim in them are opportunistic populists and divisive nationalists, destined to devour the few naïve idealists who are equally blind to the complexities of real politics. Reason might seem to be a meagre defence against such dangers, but it is the only one we’ve got.”