A Boltzmann Brain, haphazardly formed through the unlikely but still possible random assembly of physical particles, is a conscious brain having experiences just like an ordinary person. The skeptical possibility of being a Boltzmann Brain is an especially gripping one: scientific evidence suggests our actual universe’s full history may ultimately contain countless short-lived Boltzmann Brains with experiences just like yours or mine. I propose a solution to the skeptical challenge posed by these countless actual Boltzmann Brains. (...) My key idea is roughly this: the skeptical argument that you’re one of the Boltzmann Brains requires you to make a statistical inference, but the Principle of Total Evidence blocks us from making the inference. I discuss how my solution contrasts with a recent suggestion, made by Sean Carroll and David Chalmers, for how to address the skeptical challenge posed by Boltzmann Brains. And I discuss how my solution handles certain relevant concerns about what to do when we have higher-order evidence indicating that our first-order evidence is misleading. (shrink)

Some modern cosmological models predict the appearance of Boltzmann Brains: observers who randomly fluctuate out of a thermal bath rather than naturally evolving from a low-entropy Big Bang. A theory in which most observers are of the Boltzmann Brain type is generally thought to be unacceptable, although opinions differ. I argue that such theories are indeed unacceptable: the real problem is with fluctuations into observers who are locally identical to ordinary observers, and their existence cannot be swept under (...) the rug by a choice of probability distributions over observers. The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed. (shrink)

A countably infinite relational structure M is called absolutely ubiquitous if the following holds: whenever N is a countably infinite structure, and M and N have the same isomorphism types of finite induced substructures, there is an isomorphism from M to N. Here a characterisation is given of absolutely ubiquitous structures over languages with finitely many relation symbols. A corresponding result is proved for uncountable structures.

The term "spirituality" now has several interpretations, and the part acquires an excellent, even opposite, meaning in both religious and philosophical doctrines. At the same time, each under the indicated phenomenon understands something of its own. Some authors have in mind historical consciousness, others - the integrity of mental activity, others relate spirituality, first of all with the world of emotions. Undoubtedly, every interpretation of spirituality covers a certain part of the truth. It is worth noting that speaking about spiritual, (...) spirituality and its significance in human being can only be achieved by overcoming the existing bias in the scientific circles and ideological distrust of the very concept of "spirit" and "spiritual." It is not a secret that the spirituality problem was underestimated in the domestic science for a long period, which negatively affected, in particular, the understanding of its content and essence, the treatment of this phenomenon only from the point of view of materialism. From this perspective, the study of S.Prolev, who states that the spiritual exists and manifests itself in various subject forms, whose range is wide - from processes and phenomena of the human psyche to social institutions that provide spiritual production, worthy of attention. Spiritual is understood as a special reality, the "spiritual sphere" of human life. (shrink)

Of the many questions to which the RST has given rise, I should like to single out two groups.