The concept of Heaven raises innumerable difficulties but is so attractive that many may wish to believe in the idea regardless of any arguments against it. Even though unreasonable, it might play a positive role in some lives.

In ‘What on Earth is Logic?’, Michael Shenefelt and Heidi White offer this observation about the nature of logic: ‘If one tries to justify logic logically, one ends up arguing in a circle’. From this, they conclude that ‘logic is a horizon beyond which none of our earnest self-reflecting arguments can help us see’. While there is much to appreciate in how they developed this idea, there are several worrying points that could still be raised against their view. In this article, we outline such problems.

Why do logical truths exist at all, and how can our belief in them be justified? In an earlier article (‘What on Earth is Logic?', THINK 45) we contended that at least some aspects of logic must always be assumed, without argument, and that ‘logic is a horizon beyond which none of our earnest and self-reflecting arguments can help us see’. We also contended that logical truths are independent of physical facts, of social rules, and of the anatomical features of our brains. Nevertheless, in a further article in this volume, Jeremiah Joven Joaquin and Jose Emmanuel Agregado have challenged our view. We respond to their criticisms.

What can examining the introductions to books in philosophy tell us about those books, and about that discipline? This article begins by differentiating ‘insider’ and ‘outsider’ perspectives on the discipline of philosophy, questioning the most likely understanding of this division as one between professional and ‘layman’, and emphasizing instead a basic distinction between ‘affirmative’ and ‘non-affirmative’. The introduction, I suggest, is productively symptomatic of the character of contemporary philosophy. Like an owl pellet, it can tell us a lot about the kind of creature that philosophy is and the environment it inhabits.

Given how important colour is to us, it's not surprising that we have learned a great deal about colour over the centuries. However, what is much less well known – almost completely unknown outside philosophy – is the fact that colour remains a mystery: there are some simple facts about colour that lead to paradoxes that no one has been able to solve for centuries.

The ethically significant concept of being confident is analysed as the ability to face the void – an idea perhaps better studied in (Zen) Buddhism than in the West.

The gospels tell us that Judas betrayed Jesus, and that this was an incredibly wicked act. Lots of people believe that at least many of the events portrayed in the New Testament did not actually happen. I argue here that if we suppose on the contrary that they did, then Judas did not in fact act wickedly, and that the only person who acted immorally in this situation was Jesus. I refer in this article first to the wonderful story ‘Three Versions of Judas’ by Borges, who draws a somewhat different conclusion from mine, and later to Amos Oz's novel Judas.

In this dialogue I discuss the connection between eternalism (the view that past, present and future are equally real) and fatalism. I do not think, as some do, that eternalism implies fatalism, but I do think that eternalists can avoid fatalism only by denying a seemingly intuitive claim about what a traveller to the past cannot do.

The key focus in ethics should be on victims. Victims are those that suffer from unnecessary and preventable pain and misery. Non-human animals can also suffer and should therefore be included in the moral circle. Ethical living is striving to avoid harm to others and striving to help alleviate or prevent suffering. Being good isn't easy.

What would you think if someone told you they heard voices when no one was there, or could sense the presence of the dead? In some historical periods and in some societies today these experiences are made sense of positively in religious or spiritual terms, but in modern western societies they tend to be regarded as symptomatic of mental illnesses such as schizophrenia. I argue that interpreting these experiences in terms of illness can negatively affect them, turning them into something pathological when they needn't necessarily be so. I also discuss wider issues regarding illness, medicine, authority, interpretation and meaning.