Computer programs can now spot liars better than humansĚý˛ą˛Ô»ĺ predict heart attacks four hours before a doctor. But artificial intelligence isn’t trying to compete with human minds: it reasons in a completely different way that can be beyond our comprehension.

Most successful artificial brains depend on machine learning, which relies on massive amounts of data to train an algorithm for a specific goal. The approach is allowing computers to successfully perform a variety of tasks, such as gauging a person’s mood or detecting cats in YouTube videos.

Probability is at the heart of this process. Initially, artificial intelligence doesn’t “know” anything; it just assigns a probability to an outcome, such as the likelihood that a given video contains a cat. If it’s correct, it can then use that information to change the probability it assigns to the next video it encounters, and so on.

After enough cycles of guessing and receiving feedback, the algorithm will have a pretty good model of what a cat on a screen looks like.

Although we have a crude understanding of how an artificial mind works, the reasoning it uses as it crunches through a problem is often a mystery. Examining the code doesn’t provide insight into the internal logic that the machine uses.

A new technique akin to a brain scan for computers is aimed at finding out more by capturing snapshots of the process. Perhaps we will soon know as much about machine minds as they know about us.

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Is anything infinite in the physical world? Although the concept of infinity has a mathematical basis, we have yet to perform an experiment that yields an infinite result.

Even in maths, the idea that something could have no limit is paradoxical. For example, there is no largest counting number nor is there a biggest odd or even number. Although it seems like there should be half as many odd or even numbers as there are numbers in total, if both sets are infinite, in some sense we have the same amount of each.

Contradictions are more palatable in the realm of the abstract than in the real world bound by physical laws. For example, you can’t accelerate to an infinite speed as the speed of light is the cosmic limit.

The universe could be infinite, both in terms of space and time, but there is currently no way to test whether it goes on forever or is just very big. The part of the universe we are able to observe is finite, measuring about 46 billion light years in diameter. Many physicists believe it goes out further than that, an idea supported by cosmological models of the big bang and inflation.

Others think we should ditch the never-ending story. Some mathematicians are trying to rebuild the foundations of mathematics without the infinite. But if there is a biggest number, what would happen when you add one to it? The solution could be thinking of numbers as a cycle rather than a linear series, some sort of loop where you revert back to the beginning. It’s a little strange, but then so is infinity.

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FORKS up, knives down and be sure to pre-rinse. Or was it bowls down, knives up? And why do I need to rinse? Isn’t that what the dishwasher is for? Deep mystery of the universe it is not, yet proper use of the dishwasher is an endless cause of domestic turmoil.

We all have our kitchen quirks, whether reasoned or the result of years of habit. Now, finally, research provides definitive answers about which loading techniques just won’t wash.

The most common mistakes include the placement of bowls and tall items – and there are logical solutions to these dirty habits (see diagram, below). But settling more controversial dishwasher dilemmas requires a more technical approach. To study how water travels around a dishwasher, at the University of Birmingham, UK, and his colleagues injected water with radioactive tracers. They could then use the tracers to follow the movement of the water when the dishwasher was put inside a scanner. The technique, called positron emission particle tracking, revealed water direction and velocity during a normal wash cycle. It turned up a few surprising insights.

Although most dishwasher racks are rectangular, they found that around the centre maximises water flow and leads to cleaner dishes. Water velocities were lowest towards the sides and bottom of the machine, making those areas the dishes soiled with protein, such as egg yolk. The slower-travelling water allows the proteins to hydrate and swell, making them easier to wash away.

Dishes soiled with carbohydrates should go closer to the jets, where the mechanical force of the water blasts the grime away. The team found that jets are strongest near the centre of the top shelf, right above the rotating spray arm.

Of course, none of that matters if you overfill the dishwasher and the water can’t circulate properly anyway. But how much is too much? You should fill it as much as possible without stacking items on top of each other, which prevents water from reaching all soiled surfaces, says , whose group at the University of Bonn in Germany studies dishwashing habits around the world.

As for the age-old question of whether it is better to wash up by hand or use the dishwasher, Stamminger’s group found that . Given that you first have to shell out for the machine, and the research was funded by manufacturing company Bosch, you might want to take some of the findings with a pinch of dishwasher salt. Then there’s the fact that different machines vary in their efficiency. Older machines, for instance, use more water and energy. But water flows from taps at a rate of and some machines use less than that in one cycle. The calculations don’t include the water involved in making the dishwasher in the first place. And you could also argue that some hand-washing techniques will be more efficient than others.

Even so, the dishwasher’s high temperatures make for a better clean. But this has a downside too. In 2014, researchers in Sweden found that children raised in houses where manual dishwashing was the norm than those brought up in households with a dishwasher. The team speculated that less efficient washing increases exposure to microbes, leading to more robust immune systems.

Finally, the elephant in the kitchen: to pre-rinse or not? “Don’t wash your dishes before putting them in the dishwasher,” says Stamminger. Detergents are designed to bond with food residues, and if they don’t have anything to react with, they can deposit on other items, which is one cause of cloudy wine glasses. “Just scrape off any remaining food, load and let the dishwasher do the rest,” says Alex Lucas at dishwasher manufacturer Bosch in Milton Keynes, UK. Now all that’s left to argue about is whose turn it is to put the dishes away.

(Image: Adam Pointer)

This article appeared in print under the headline “Fully loaded”