The tricky cause and effect relationship

We are always warned that a statistical correlation should not be used to infer causation because either the causal relationship can go either way or both effects may be due to a third cause. The only way to truly determine the direction of causality is to design experiments that are specifically meant to tease it out. But sometimes we can be fooled by multiple, seemingly independent correlations that strongly suggest causality. A recent study of vitamin D deficiency and health illustrates this danger. [Read more…]

Heat is bad for the soul

If there is one thing that religions absolutely must believe in, it is the existence of the soul, although not all religions give it the same name. Without the belief that there is some entity that is part of us and yet somehow independent of the body and can interact freely with an external deity, much of religious doctrine becomes even more vacuous than it currently is. [Read more…]

Moon illusion

You may have heard about ‘moon illusion’, the way the full moon looks much larger when it is just over the horizon than when it is high in the sky. Many people will swear that it actually does appear larger and concoct theories as to why it is so, when the reality is that the larger size is a trick our brain plays on us, though there is no consensus on how it does it. In an earlier post I examined some of the explanations. [Read more…]

The origins of complexity

Life is complex. This is true not just in a rhetorical sense but also biologically in that living things are complicated arrangements of multicellular life. So how did this complexity arise? The most common explanation given is that it is a natural outgrowth of natural selection and that once a self-replicating molecule formed, the selection pressures would be such that given sufficient time multicellular life would be an almost inevitable consequence, though the exact form it would take would depend on many contingencies. [Read more…]