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…]
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…]
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…]
My earlier post on the origins of complexity sparked an interesting and informative discussion in the comments so I thought I would pass on another article about it by Amy Maxmen that I came across later, that looked at the same question in light of what we know about the seemingly lowly amoeba. She starts by posing the problem. [Read more…]
A crucial step in the evolution of complex organisms is the appearance of multicellularity. Key questions are “how did multicellularity evolve? Did it evolve once or multiple times? How did cells make the transition from life as a solo cell to associating and cooperating with other cells such that they work as a single, cohesive unit?” [Read more…]
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…]
Neurophilosopher Patricia Churchland appeared on The Colbert Report to discuss with the host some of the latest developments in neuroscience and what they shed on old philosophical questions. She had to break the news to him, a practicing Catholic, that he has no soul (because none of us do) and that our moral sense arises from the circuitry and chemical activity of the brain. It is a good interview. He actually asks some sharp questions, dealing with the kinds of concerns a religious person would have, and gives her time to respond rather than taking up a lot of the time which can be a failing of his. [Read more…]
The discovery of the Tiktaalik fossil back in 2006 was a cause of great celebration because it was a 385 million year old fossil that showed the early stages of forelimbs that indicated it was a transitional one from sea to amphibian. Neil Shubin, the leader of the team, wrote a highly engaging book Your Inner Fish that showed how much our human bides were shaped by our fishy ancestors. [Read more…]
Everyone is aware of all the reports that suggest that our cognitive powers go into decline with increased age. As a result, as some of us get into our senior years, we can’t help but identify as symptoms of that mental decline every time we do not remember some thing that we think we should, or when it takes awhile to do something that we think we used to do faster. We may joke about having ‘senior moments’ but those jokes are accompanied by a twinge of anxiety as to whether they are precursors of more serious problems to come. [Read more…]