Skye is truly a landscape fashioned by geology. Renowned for its ancient formations, this rugged island is home to some of the oldest rocks on Earth. The sheer variety of life demonstrated by these fossils can be explained by the different climatic conditions which Scotland underwent as a result of the movement of huge tectonic plates, causing this country to drift northwards from an original position near the South Pole to the equator, and beyond. Over huge periods of time, the island endured everything from arctic conditions to a tropical climate and even hot deserts, resulting in some of Scotland's most dramatic scenery, with towering pinnacles looking out over the Atlantic.

The island's oldest rocks are the Lewisian gneisses of the Sleat Peninsula, formed underground 2.8 billion years ago from a variety of even older rocks. These were forced to the surface about 1.1 billion years ago before being buried by several thousand metres of gritty and pebbly sandstones from fast-flowing rivers. Looking down upon the island from above, large extinct volcanoes - now much eroded - can be seen forcing their way through the centre of this ancient mass, forming the island's lofty Cuillin hills. From their famous jagged peaks, peregrines and golden eagles watch over the lands below. Apart from these raptors and the occasional rock climber, these heights are devoid of life. It is necessary to descend a little in order to reach the first upland inhabitants of the island, the abundant red deer, which thrive here thanks to Skye's distinctive geology.

Towards the end of Scotland's last glacial period, approximately 15,000 years ago, a huge sheet of ice completely covering the island began to melt, exposing stony soils. This, combined with the island's position on the exposed west coast of Britain, notable for its above-average rainfall, resulted in extremely boggy terrain. Plants attracted to the resulting acidic conditions - such as sedges and lichens - began to colonise the landscape, followed by scattered alpines and a variety of rare plants including butterwort, notable for its unusual method of trapping and consuming insects on its sticky leaves. These prove ineffective against larger herbivores though, including the aforementioned deer who feed indiscriminately. Interestingly, perhaps due to the red deer's dominance, there are relatively few other established land mammal populations on the island. However, with the recent opening of the Skye Bridge, connecting the island to the mainland, further species - most notably pine martens, elusive woodland creatures similar to large weasels - have also arrived and settled permanently.

Although the distance from the northernmost point of Skye to its southernmost is a mere 65 miles, the island's coastline amounts to an extraordinary 456 miles. This gives some idea of the intricate coastline and all the bays and headlands that surround Skye and harbour the majority of its unique ecosystems. Fishermen, as well as otters and mink, are attracted to the rich abundance of shellfish to be found in the island's coastal inlets and reefs. Above these, the high columnal cliffs provide nesting spots and lookouts for white-tailed sea eagles which take fish and the aforementioned small mammals directly from the sea. Below these cliffs, Skye's numerous grey and common seals can be spotted entering and exiting the sea from their bases on the many flat islets around the southern and western coast, which mirror a geological feature of particular note known as 'MacLeod's tables' - flat-topped hills formed by the erosion of paleocene lavas. One further feature of Skye's coastal geology is that the sheltered inlets provide an ideal refuge for groups of dolphins and porpoises, away from the storms of the Atlantic.

Further out towards this oceanic expanse, a wealth of species take advantage of the nutrient-rich waters typical of the Sea of the Hebrides. The first benefactors are plankton, which bloom each Spring and attract a host of predators including forage fish, such as herring. The most renowned visitor to the island's waters, the colossal basking shark, also feasts during these springtime occurrences and can often be spotted from island viewpoints doing so. Vast kelp forests, which thrive in such waters, especially on relatively shallow bedrock to which they can easily anchor, dominate the seabed further out to sea and play a vital role in maintaining the nutrient quota. The plant's incredible height - up to thirty metres - also provides living space for a number of species. In addition, when the vegetation eventually dies, it produces flakes of plant material which break down and dissolve, in the process providing food for single-celled animals.

The vast windy open waters to the south-west of Skye mean it has great potential as a base for wind farms and the harvesting of renewable energy, though this is not the only example of Skye's inhabitants benefitting from their host's billion-year history. Land in the east of the island, where limestones created a smooth well-drained area of grassy slopes, were long ago found to be particularly fertile and continue to be farmed. Nowadays it is wildlife and outdoor tourism that form the main economy of the island. In recent years, tourism itself has been boosted thanks to the featuring of the island in films, such as Prometheus which prominently featured the striking blocks and pinnacles of the Trotternish peninsula, the result of basalt lava landslides around fifty million years ago.

A Rationality is defined as the quality or state of being reasonable. Being a "rational person" involves basing one's decisions on consideration of facts and logical thinking, rather than on intuition, belief and emotion as is the natural tendency of human beings. The study of rationality is a blend of philosophy, economics, sociology, psychology, evolutionary biology and political science. People who identify as "rationalists" strive to improve their critical thinking and decision-making skills in order to live in a more rational manner.

B Since the turn of the 21st century, rationality has experienced a rising popularity and several devoted online communities have formed to champion and teach rational thinking. Perhaps the most notable of these is Less Wrong, a community started in 2006 by artificial intelligence researcher Eliezer Yudkowsky and economist Robin Hanson. Any community member can participate by attending regular 'physical' meetups in different cities around the globe or spark debate by posting on its website or forum. User Raemon attempts to define what “the rationalist community” consists of. He outlines two levels of the community as he sees it: the ‘Rationalsphere’, comprising everyone with an interest in rationality, regardless of their interest in joining a community; and the ‘Rationality Community’, containing those who want to connect over their interest.

C He goes on to define features of those two levels. In reference to the ‘Rationalsphere’, he adds 'overlapping patterns of thought', stating that, although there is no one feature to define people in this camp, they share some habits and patterns, such as being attentive to the unreliability of one's mind or being willing to change one's preconceived ideas. He further highlights three focus areas: truthseeking, impact and what he simply terms as ‘human’. The first deals with aiming to improve our thinking and applying that knowledge to better understand the world, while the next concerns applying that new mindset to make a real difference in the world. The final focus area relates to one's own life and how it can be improved along with the lives of those close to us through the application of rationality techniques. The 'Rationality Community' is still centred on these same ideals, yet is able to focus on them more intensely due to being directly involved with a like-minded set of others. The two aforementioned camps along with the focus areas mentioned are active rationality community examples of Yudkowsky's theory that it is possible to improve the quality of our decision-making processes by applying logic and understanding of probability to our day to day lives.

D The standard process for debate on Less Wrong involves community-generated articles prompting responses from other community members through the Less Wrong voting system. Readers can award points for the usefulness or not of the piece, from which users are awarded 'karma'. The higher this is, the more respected and valued a user's contributions are deemed to be. Through this system on its website and forum, Less Wrong community members debate concepts such as decision making and economic theory, for example, as well as training each other in practical techniques. The project has spawned other rationality communities, including the Center for Applied Rationality, a non-profit organisation in Berkeley, California which runs workshops on critical thinking and setting goals, and offline clubs, such as the New York City Sceptics and Bay Area Rationalist Community.

E One motivation for the study of rationality techniques is the view that humans are naturally irrational creatures. Science writer David Berreby notes that people generally cannot tell when they are being rational, cannot become more so by willpower alone and often believe their behaviour is rational when, in fact, it is not. He raises the example of court judges, whose remit is to be unbiased authorities of the law. In a research study conducted by German psychologists Englich, Mussweiler and Strack, it was found that judges who rolled a die before adjudicating a case would give a longer sentence if a higher number came up than those who rolled a lower number. This demonstrates that even trained rational thinkers - and judges surely fall into this category - are influenced by natural irrational tendencies.

F However, not everyone thinks that people are naturally irrational and require “fixing”. Dr Steven Mazie, a correspondent for The Economist, believes this idea stems from what he calls a "faddish denial that human beings can think straight". He is of the opinion that humans are rational creatures, despite the current trend to cast them in the opposite light. Other commentators have also called into question the fundamental basis of rationality communities such as Less Wrong - that being irrational is a bad thing. Henry Brighton, professor of computer science at Tilburg University, explains that objective data is a rarity in most real-world situations. As a result, logical formulations are an inappropriate method of decision-making and most important decisions rely, at least partially, on a person's subjective preferences.