On the origin of species by Charles Darwin

The book is about Struggle for Existence. You might say it is no more relevant today for we, at least people in the West, have passed the stage of Struggle for Existence. But wait! How did Darwin understand Struggle for Existence?

I should premise that I use the term Struggle for Existence in a large and metaphorical sense, including … not only the life of the individual, but success in leaving progeny. (P. 62)

From Darwin’s definition, the Western societies are doing terrible in the Struggle for Existence. For Darwin, unless the idea of struggle for life is thoroughly engrained in the mind, we can’t really understand the world.

Nothing is easier than to admit in words the truth of the universal struggle for life, or more difficult--at least I have found it so--than constantly to bear this conclusion in mind. Yet unless it be thoroughly engrained in the mind, I am convinced that the whole economy of nature, with every fact on distribution, rarity, abundance, extinction, and variation, will be dimly seen or quite misunderstood. We behold the face of nature bright with gladness, we often see superabundance of food; we do not see, or we forget, that the birds which are idly singing round us mostly live on insects or seeds, and are thus constantly destroying life; or we forget how largely these songsters, or their eggs, or their nestlings, are destroyed by birds and beasts of prey; we do not always bear in mind, that though food may be now superabundant, it is not so at all seasons of each recurring year.  (P.62)

Even when our struggle for existence seems to direct toward external factors, such as climate, the struggle between our fellow living organisms are much more intense.

Even when climate, for instance extreme cold, acts directly, it will be the least vigorous, or those which have got least food through the advancing winter, which will suffer most. When we travel from south to north, or from a damp region to a dry, we invariably see some species gradually getting rarer and rarer, and finally disappearing; and the change of climate being conspicuous, we are tempted to attribute the whole effect to its direct action. But this is a very false view: we forget that each species, even where it most abounds, is constantly suffering enormous destruction at some period of its life, from enemies or from competitors for the same place and food; and if these enemies or competitors be in the least degree favoured by any slight change of climate, they will increase in numbers, and, as each area is already fully stocked with inhabitants, the other species will decrease. When we travel southward and see a species decreasing in numbers, we may feel sure that the cause lies quite as much in other species being favoured, as in this one being hurt. So it is when we travel northward, but in a somewhat lesser degree, for the number of species of all kinds, and therefore of competitors, decreases northwards; hence in going northward, or in ascending a mountain, we far oftener meet with stunted forms, due to the directly injurious action of climate, than we do in proceeding southwards or in descending a mountain. (P. 67)

All the above quotes are from Chapter three: Struggle for Existence. It is, in my opinion, the best written chapter. This chapter is worth reading again and again.