Several theoretical frameworks have been proposed to explain the physiological basis of pain, although none yet completely accounts for all aspects of pain perception. Here, we provide a historical overview of the major contributions, ideas, and competing theories of pain from ancient civilizations to Melzack and Wall's Gate Control Theory of Pain.

The concept of number and its generalization has played a central role in the development of mathematics over many centuries and many civilizations. Noteworthy milestones in this long and arduous process were the developments of the real and complex numbers which have achieved universal acceptance. Serious attempts have been made at further extensions, such as Hamiltons quaternions, Grassmann’s...

Recent prescriptions for rescuing civilization from collapse involve extending our human capacity for empathy to a global scale. This is a worthy goal, but several indications leave grounds for cautious optimism at best. Evolutionary biology interprets non-kin helping behaviors as products of natural selection that rewarded only the transmission success of resident genes within ancestors, not t...

It is generally recognized that life is becoming more complex. This article analyzes the human social environment using the "complexity profile," a mathematical tool for characterizing the collective behavior of a system. The analysis is used to justify the qualitative observation that complexity of existence has increased and is increasing. The increase in complexity is directly related to swe...

Aztec culture flourished in the highlands of central Mexico between the twelfth and sixteenth centuries, AD. As the last in a series of complex urban civilizations in Mesoamerica, the Aztecs adopted many traits and institutions from their predecessors such as the Maya and Teotihuacan. The Aztecs also devised many innovations, particularly in the realms of economics and politics. Aztec civilizat...

The author questions the extent to which Freud's theory of culture can justify Freud’s postulated claim concerning the social causation of neuroses. Since the premises on which Freud bases his cultural theory are untenable, it is argued that this justification cannot be supplied by it. This is followed by an examination of Freud’s arguments against historical materialism, and a further reasoned...

In the anoxic Cariaco Basin of the southern Caribbean, the bulk titanium content of undisturbed sediment reflects variations in riverine input and the hydrological cycle over northern tropical South America. A seasonally resolved record of titanium shows that the collapse of Maya civilization in the Terminal Classic Period occurred during an extended regional dry period, punctuated by more inte...

The first advanced Bronze Age civilization of Europe was established by the Minoans about 5,000 years before present. Since Sir Arthur Evans exposed the Minoan civic centre of Knossos, archaeologists have speculated on the origin of the founders of the civilization. Evans proposed a North African origin; Cycladic, Balkan, Anatolian and Middle Eastern origins have also been proposed. Here we add...

The lack of evidence for the existence of extraterrestrial life, even the simplest forms of animal life, makes it is difficult to decide whether the search for extraterrestrial intelligence (SETI) is more a high-risk, high-payoff endeavor than a futile attempt. Here we insist that even if extraterrestrial civilizations do exist and communicate, the likelihood of detecting their signals cruciall...