(This is a repurposed Facebook comment.)

The Fine-Tuning Argument (FLA) is accused of committing the Texas sharpshooter fallacy. Sam the shooter wants to hit a bullseye, but isn’t having much luck. They can barely hit the side of a barn. Having sprayed bullets at the barn all day, they devise a plan: pick an arbitrary bullet hole, paint a bullseye around it, ignore the rest of the bullet holes, and announce themselves to be a sharpshooter.

The moral of this story can be stated in a few ways. Don’t ignore data. Keep in mind the number of failed attempts when you go looking for (and set a criterion for) successful attempts. You can avoid these problems if you specify your hypothesis before you collect your data. Drawing conclusions from a sub-sample is dangerous – if you must, try to choose a random sub-sample.

A Bayesian Sharpshooter

Let’s put the tale of Sam in Bayesian terms, and then see if it applies to the FTA. Suppose,

  • S = Sam is a sharpshooter
  • \bar{S} = Sam is not a sharpshooter.
  • T = Sam said “I’m going to hit that painted bullseye with this shot”, and then he did.
  • P = Sam shot at a wall, and then painted a bullseye around his shot.
  • B = background information about guns and bullets and such.

In both cases T and P, we observe a bullet at the centre of a bullseye. The difference between the cases is as follows. Sharpshooters are much more likely to hit a given target than non-sharpshooters, thus: Continue Reading »


Want to simulate some other universes with me? Looking for life in a (simulated) cosmos? Desperate to test some multiverse theories? You too could make classy videos like this!

Using supercomputer simulations of galaxy formation, we will investigate the effect of fundamental cosmological parameters on structure in the universe. We will model the formation of galaxies in lumpier and smoother sub-universes, and universes with different amounts of dark matter. Our group has previously explored the effect of the cosmological constant (arxiv.org/abs/1801.08781), and will extend and expand this approach, working with a world-leading galaxy formation code.

What does the scholarship provide?

  • Domestic students will receive a tax-free stipend of $30,000 per annum for up to 3 years to support living costs. Tuition fees will be supported by the Research Training Program (RTP) Fees Offset.
  • International students will receive a tax-free stipend of $30,000 per annum to support living costs. Those with a strong track record will be eligible for a tuition fee waiver.
  • All international students are required to hold an Overseas Student Health Care (OSHC) policy covering the duration of study, with the scholarship including funding for Single cover.
  • Support for conference attendance, travel and additional costs as approved by the School.

For eligibility conditions, and to apply, see the details here.

Applications close on October 14.

Please share this!

I’ve got a few talks upcoming in Sydney. Come and see the show!

2 August 2018, Sutherland Astronomical Society

Title: Following Light to the Beginning of the Universe
Time: 7:30pm – 9:30pm
Location: Green Point Observatory, Oyster Bay
Free. (I think. Maybe a gold coin for tea and coffee). More details here.

Abstract: How do we know what the Universe is made of? And what shapes its parts into the stars, galaxies and clusters of galaxies that we see around us? Starting from the very early universe, I’ll discuss how the fundamental factors of our universe, its forces, particles, and the dynamical stage that they tread (space time), compete and cooperate to fashion the Universe today.

5 August 2018, St Mark’s Darling Point

Title: The Big Questions – Science and God
Time: 8am, 10am and 5:30pm
Location: 1 Greenoaks Ave, Darling Point NSW 2027
More details here.

10 August 2018, The Australian Botanic Garden (Mount Annan)

Event: Stars over the Garden

Come and enjoy the beautiful Garden under a starry sky! You will learn about Western and Aboriginal views of the night sky.

Dr Luke Barnes, astronomer at Western Sydney University will introduce you to the night sky over Mount Annan and the Macarthur Astronomical Society will bring out their telescopes so you can experience the best views. Our Aboriginal educators from Shared Knowledge will share their dreamtime stories about Australian sky and talk about how the visibility of certain star signs influences their lives.

If the weather permits you will have the opportunity to watch the stars and planets close up through the telescopes. A glass of wine will round up an amazing night experience.

Time: 4.45 pm-6.15 pm
Location: Narellan Road, Mount Annan 2567
Cost: $29.00 per person / Garden member $25.00. No walk-ins. Tickets must be purchased in advance here.

13 August 2018, St. Luke’s Clovelly

Title: The Big Questions – Science and God
Time: 7.45 for snacks, 8pm start
Location: Corner Arden St and Varna St, Clovelly (location)
More details here.

17 August 2018, Centennial Park

Event: Astronomy in the Park

Immerse yourself into a night of stargazing. Looking up we see the bright and the dark – explained by our scientists of the Sydney Observatory, and by our aboriginal educator who will share his stories about the sky with us. At our telescope station, you will have the chance to observe the sky and ask our scientists about the phenomena you discover.

Once you and your group have discovered the sky and the park, we will wind up the evening at a campfire where you can relax, reflect the stories you heard, and enjoy a night in the park under the stars.

Time: 5pm-7pm
Location: Wild Play Discovery Centre, Dickens Drive, Centennial Park
Cost: $29.00 adults / Children $15.00. Find more details and purchase tickets here.

21 August 2018, Narrabeen Baptist

Title: The Big Questions – Science and God
Time: 7:30pm – 9pm
Location: 13 Grenfell Ave, North Narrabeen (location)
More details here.

I’ll be speaking at St Hilary’s in Melbourne tomorrow, on the topic of the fine-tuning of the universe for life. It’s free!

Time: 8pm-9:30pm, 29th May, 2018
Location: 12 John St, Kew Victoria
More details here.

My most recent paper with Pascal Elahi (UWA), Jaime Salcido (Durham), Richard Bower (Durham) and Geraint Lewis (Sydney), as part of the Eagle Collaboration, is doing the rounds of the popular press. I’ll post some of the articles here, and keep updating. Check out the video!

I did this research (mostly) while at Sydney University, but I’ve started a new position at Western Sydney University – more details soon.

  1. Sydney Morning Herald: Bad news for the multiverse: it’s still not likely Also, the Canberra Times and The Age (Melbourne).
  2. Cosmos Magazine: Multiverse theory cops a blow after dark energy findings
  3. IFLS: If A Multiverse Exists It Could Abound With Life
  4. Newsweek: What Is The Multiverse? Parallel Universes Could Be Hospitable To Life, Scientists Say
  5. The Independent: We could live inside a multiverse that is full of alien life, new study suggests
  6. Astrobiology Magazine: Could a multiverse be hospitable to life?
  7. inverse.com: New Multiverse Research Suggests Scientists Need a New Law of Dark Energy
  8. Geek.com: Science Says: Multiverse May Sustain Life
  9. The Register: Get over yourselves: Life in the multiverse could be commonplace
  10. New Atlas: Simulations suggest multiverse is either teeming with life – or doesn’t exist
  11. EarthSky: Is there life in the multiverse?
  12. Eureka Alert: Could a multiverse be hospitable to life?
  13. Science Alert: The Multiverse Could Be Teeming With Life But Is Also Problematic, Says New Study
  14. Inquisitr: New Research Questions The Multiverse Theory, Calls For A New Law Of Dark Energy
  15. Bizsiziz.com: The Multiverse Could Be Teeming With Life But Is Also Problematic, Says New Study
  16. Advocator: Could There Be Life in the Multiverse?
  17. India.com: A multiverse may be hospitable to life: study
  18. Silicon Republic: Mysterious force could determine whether life exists in multiverse
  19. Sputnik News: “Multiverse” May Be Hospitable to Life After All
  20. whatsnew2day.com: Bad information for the multiverse: it is nonetheless not going
  21. scienmag.com: Could A Multiverse Be Hospitable To Life?
  22. International Business Times: Multiverse’s High Dark Energy Levels Don’t Hamper Life’s Chance Of Existing Elsewhere
  23. TheTeCake: New find on multiverse shocks scientists!

I’ll be speaking at The Atrium Theatrette in Perth next thursday, on the topic of the fine-tuning of the universe for life. It’s a ticketed event, but you get drinks and canapes for your $30.

Time: Thursday 10 May, 5.30pm-8pm
Location: The Atrium Theatrette, Level 4, 168 St Georges Terrace, Perth
Tickets: Follow the link here.


I’ll be speaking at University Of Technology, Sydney on Monday 16th April, 2018. This event was originally pitched to me as another talk about the book, but has since evolved into a four-person discussion/debate event with Prof Peter Slezak (UNSW), Ian Bryce, and Mike Paget.

You may be familiar with Prof Slezak from his very interesting debates with Dr William Lane Craig, which I’ll put below. So I’m hopeful for an entertaining evening.

Time: April 16, Monday 6.30-8.30pm
Location: Aerial Function Centre @ Building 10, Level 7

This is a ticketed event – $10. I have no idea why. Book your tickets at Eventbrite.


Peter Slezak videos …