If we made contact with an alien species which was clearly intelligent/sentient, but at a very different level to us, for example, if in the future humans found a planet inhabited by a species which was approximately as intelligent as our distant ancestors (and ancestors which were less intelligent than us for genetic, not simply environmental reasons), should we consider one alien to be as important as one person? Whatever conclusion I come to seems to throw up problems: if we say yes, then should we consider the life of a chimpanzee to be as important as that of a human? If we say no, then presumably we would have to concede that if we met aliens more intelligent than us then we would be less important than them. Or perhaps there's a base level of intelligence above which all sentient beings are equal, but how would we determine that base level? On the other hand, if we move away from intelligence and look for something else like signs of a capacity for love or mourning to evaluate a species moral...

I think it is important to distinguish intelligence from sentience. As you suggest, it is possible that there exist beings that are much more intelligent than humans are just as, for example, humans are much more intelligent than, say, dolphins. On the other hand, I don't think it makes sense to treat sentience in this way: it isn't the case that a being much more intelligent than us is also much more sentient than us. Rather, I think it makes more sense to say of any being that it is either sentient or not -- and then perhaps also note that differences in mental lives, sensory apparatuses, etc. mean that different types of beings are "differently" sentient (but not more or less sentient). This distinction is important because sentience could be taken to be an important criterion for moral considerability: one might well believe that the moral claims of sentient beings are stronger than the claims of non-sentient beings. If this were the case, then all sentient creatures, no matter how intelligent,...

Who are some philosophers who wrote about the value and conditions of work, other than Marx?

Other historical figures who write on these themes are Plato,Aristotle, Aquinas, Hobbes, Locke, Hume, Kant, and Mill. Many of thesethinkers discussed together in intriguing ways private property rightsand the value of work, and I think that Marx's arguments bearinteresting relations to, for example, Locke's and Hegel's views onthat. After Marx, Dewey and Arendt wrote on the large theme you nameas do many contemporary philosophers working in the fields of politicalphilosophy, feminist philosophy, business ethics, and environmentalethics -- probably any large-scale anthology of recent work in thosefields will include some relevant material. Marx's views aren't discussed as much these days as they were, say, in the late 1970s and 1980s whenGerry Cohen, John Roemer, Tom Bottomore, Alexander Callinicos, andothers did much high-quality work in what was sometimes called"analytical Marxism." Those folks' critical work includes usefuldiscussions of how Marx's ideas on work relate to work earlier in...

Should the retrospective ideas, advice, and wisdom of a dying person be heeded and followed in our own lives? That is, if a dying person wishes they would have lived in a different way, or says that certain things were the most valuable, should we follow this advice, and even change our lives to suit?

To add to my colleague’s excellent comment, one might think that, for manyof us at least, dying is such a stressful time--with respect to health,emotionality, family dynamics, etc.--that a dying person is in a relativelypoor position to form and communicate considered wisdom about life. To be sure, for some the perspective of one's imminent death might be usefuland constructive (as, for example, Hegel asserts when he defends the ethicalutility of warfare), but I suspect that popular culture tends to exaggeratethis possibility.