17/09/2015 11:36 BST | Updated 16/09/2016 06:12 BST

31 Questions to Give Your Brain a Workout

Sudoku, crossword, brain-training apps - they've all been plugged on the basis of their ability to keep your mind active and healthy. I don't for a moment doubt the restorative powers of a puzzle, but for me, there's a more challenging and fulfilling way not only to keep your brain fit, but also to add fire to your conversations and depth to your understanding. Philosophy.

In an interviews a while back I was asked what were some of the great questions touched on by my novel The Human Script, which has been described variously as "a philosophical thriller" and "a novel of ideas".

The result was the following. A list of what I called 'ponderables' - 31 questions that will get you thinking about some of life's unknowables. That's one a day for you for the next month. Use them to give your brain a stretch on the way to work or to shoot the breeze with colleagues.

Please enjoy - and feel free to share your thoughts.

On free will and determinism

1) Could the future ever turn out otherwise than how it will have turned out?

2) If a butterfly flaps its wings, can it have no effect whatsoever?

3) Could anything ever happen without being caused by something else?

4) If what we do is influenced by nature and nurture, what room does that leave for free will?

5) Which constrains you more? Your genetic inheritance or your personal history?

6) Can you make choices on instinct and still be said to be exercising free will?

7) How do your genes and your environment impact what you do? Could you ever know which causes what?

8) If you take a drug - and cannot help doing so because of addiction - do you still have free will?

9) If a drug makes you act a certain way, do you still have free will?

10) If two clones cannot be in the same place all the time, in what ways might that make them different?

11) Can we change ourselves? Or are we changed by influences? Can wanting to change come from outside the self?

12) If I decide something, who is "I"? My brain, my soul, my environment, my genes?

13) If you decide to change yourself, will you still be you afterwards? Why?

14) If God knows all, he knows what you'll decide. So, is an omniscient god reconcilable with idea of free will?

On art and literature

15) Does art have to be good to be art?

16) Can an idea be an artwork itself or does there have to be a physical artwork that expresses that idea?

17) Could a fictional character be said to exercise free will? Would they think that they can?

18) How do you know you're not a fictional character?

19) Does a fictional character feel pain?

20) Do novelists play god? Do they have a moral duty to their characters?

21) Is the 'soul' separate from the physical self? If so, where is it? Can fictional characters have one?

22) If something is true, then anything that contradicts it must be false. Is the same true in fiction?

23) Fiction is made up, but tries to be true to life. Is that possible if it's all just artful lying?

On celebrity

24) If a famous person is different from their public persona does that mean the 'celebrity' isn't real?

25) What if a celebrity turned out to be a hoax, a fiction? Should it matter to their fans?

On life, sex and happiness

26) Is your sexuality what you feel or what you do? What if they're different?

27) How do you know whether you're happy?

28) Could suicide ever be a rational choice?

On faith and reality

29) Do you need faith to believe in the scientific method?

30) Is there a difference between believing something is true and knowing it? Don't you have to believe that you know something?

31) For something to be perfect, does it have to be real? Isn't failure to exist an imperfection?

By the way, if you want the answers, you can look them up in my novel. They're all in there somewhere.