10.  Religion in numbers (Part 1)

How many people are there on Earth?


One of the most fascinating areas of study for any philosophy club revolves around gaining a clear understanding of the demographics of religious belief. Despite the potentially dry sounding nature of this form of enquiry it is actually incredibly popular with students who are often left amazed by the sheer number of people on our planet and the diversity of religions and beliefs. This series of sessions is designed to give students an introduction to this absorbing and intriguing field.

Whilst ‘How many people are there on Earth?’ is not strictly speaking a philosophical question because there is, in theory at least, a straightforward scientific answer, it is nevertheless a fascinating question. Firstly, very few students, in my experience have a clue about just how many people there are on the planet.


As an opening activity, ask the students to guess the world’s population and write it down in a series of digits (e.g. 6,000,000 rather than 6 million). I have invariably found that the guesses range wildly between a few thousand and several billion.

Ask them a further question:

Assuming that all the guesses were different it is well worth taking the time to discuss these differences. Ask the students why they guessed what they guessed. This can allow for a very revealing discussion about authority sources and the concept of ‘educated guessing’.

Once the discussion has finished reveal that the real answer is somewhere around 7,000,000,000 (7 billion). Make sure that you write the figure down and compare it to the number of students in your school and town. For example:

School: 1,000

Town: 20,000

UK: 68,000,000

World: 7,000,000,000

This allows students to get a feel for the numbers far more than they would if they were simply told the world population was 7 billion.


Encourage the students to reflect on the difficulty of keeping tabs on an ever changing human population:

Discussing this question allows you to get the students reflecting on the difficulty of keeping tabs on an ever changing human population. How do scientists know when somebody is born or somebody dies? It also allows you to introduce the notion of a census and, again, stress the concept of ‘educated guessing’:

This is a fantastic question because it will allow you to explain that the population has grown by more than 1 billion since the turn of the millennium (when it was just under 6 billion). If you want to you can stress the fact that the human population first topped the 1 billion mark in the early 1800’s and that this means that more people have been added to the world’s population in the space of their lifetime than existed in 1850!


Show students the ‘World Population Clock’ at:


Ideally, if you get a chance to get the students to look at this website on their own in an ICT suite they can follow their own lines of enquiry and interest. I have yet to work with a group of youngsters who are not fascinated by this website. It is worth stressing that the site is not totally accurate due to all the difficulties with getting accurate data on populations. If you cannot book an ICT suite it is still worth getting the site up on a big screen and discussing some of the fascinating facts on the homepage including:

Ask them also to comment on the graph which shows the growth of the human population over time.


Conclude the session by asking what the most fascinating thing the students learnt today was.

A printable (pdf) version of this session can be found here

Sea of Faith Network is a Registered Charity, number 1113177



Sea of Faith Network

Resources for Schools

Home   About SoF   Meetups   What’s On   Sofia Magazine   Articles   Links   Contact Us

List of Topics