Problem: Most of Hume's followers have disagreed with his conclusion that belief in an external world is rationally unjustifiable, contending that Hume's own principles implicitly contained the rational justification for such a belief, that is, beyond being content to let the issue rest on human instinct, custom and habit. According to an extreme empiricist theory known as phenomenalism, anticipated by the arguments of both Hume and George Berkeley, a physical object is a kind of construction out of our experiences. Phenomenalism is the view that physical objects, properties, events (whatever is physical) are reducible to mental objects, properties, events. Ultimately, only mental objects, properties, events, exist hence the closely related term subjective idealism. By the phenomenalistic line of thinking, to have a visual experience of a real physical thing is to have an experience of a certain kind of group of experiences. This type of set of experiences possesses a constancy and coherence that is lacking in the set of experiences of which hallucinations, for example, are a part. As John Stuart Mill put it in the mid-19th century, matter is the "permanent possibility of sensation". Mill's empiricism went a significant step beyond Hume in still another respect: in maintaining that induction is necessary for all meaningful knowledge including mathematics. As summarized by D.W. Hamlin:
What is phenomenalism?
The answer is the following: physical objects, properties, events (whatever is physical) are reducible to mental objects, properties, events

Problem: Pelayos' plan was to use the Cantabrian mountains as a place of refuge and protection from the invading Moors. He then aimed to regroup the Iberian Peninsula's Christian armies and use the Cantabrian mountains as a springboard from which to regain their lands from the Moors. In the process, after defeating the Moors in the Battle of Covadonga in 722 AD, Pelayos was proclaimed king, thus founding the Christian Kingdom of Asturias and starting the war of Christian reconquest known in Portuguese as the Reconquista Crista.
In which battle did Pelayos defeat the Moors?
The answer is the following: Battle of Covadonga

Problem: The first institute of madrasa education was at the estate of Hazrat Zaid bin Arkam near a hill called Safa, where Hazrat Muhammad was the teacher and the students were some of his followers.[citation needed] After Hijrah (migration) the madrasa of "Suffa" was established in Madina on the east side of the Al-Masjid an-Nabawi mosque. Hazrat 'Ubada bin Samit was appointed there by Hazrat Muhammad as teacher and among the students.[citation needed] In the curriculum of the madrasa, there were teachings of The Qur'an,The Hadith, fara'iz, tajweed, genealogy, treatises of first aid, etc. There were also trainings of horse-riding, art of war, handwriting and calligraphy, athletics and martial arts. The first part of madrasa based education is estimated from the first day of "nabuwwat" to the first portion of the "Umaiya" caliphate.[citation needed]
What type of physical fitness activities were taught in the early madaris?
The answer is the following: athletics and martial arts

Problem: The origins of the department store lay in the growth of the conspicuous consumer society at the turn of the 19th century. As the Industrial Revolution accelerated economy expansion, the affluent middle-class grew in size and wealth. This urbanized social group, sharing a culture of consumption and changing fashion, was the catalyst for the retail revolution. As rising prosperity and social mobility increased the number of people, especially women (who found they could shop unaccompanied at department stores without damaging their reputation), with disposable income in the late Georgian period, window shopping was transformed into a leisure activity and entrepreneurs, like the potter Josiah Wedgwood, pioneered the use of marketing techniques to influence the prevailing tastes and preferences of society.
When did the idea of a "consumer society" begin?
The answer is the following:
at the turn of the 19th century.