Is there an afterlife? The Lancet-published cardiologist Pim van Lommel believes there is. I believe his central statements are based on inaccurate (interpretation of) measurements.
Based on findings on Near Death Experiences (NDE) that he reported upon in the Lancet, van Lommel recently wrote a popularized book in which he explains his beliefs and research findings to a larger public. There, he argues that our consciousness is not located within our physical body. As could be expected, this book (called `Endless Consciousness’, my translation) raised a lot of discussion between ‘believers’ and ‘critics’.
But let’s take a closer look at the peer-reviewed research findings on which the statements on the afterlife are based. In the Lancet article, Van Lommel and colleagues do not speak of the existence of an afterlife, but refer to the locality of our consciousness. In an intelligent research design, van Lommel and colleagues asked hospitalized cardiac patients to participate in his research. In case these people had a cardiac arrest, from which they were successfully reanimated, these people were surveyed on whether or not they had experienced a Near Death Experience (NDE) and if so, what exactly their experiences during the NDE were.
Based on this design, Van Lommel was able to show that from the people who survived the cardiac arrest, approximately 18% had a Near Death Experience. Existing explanations on the prevalence of NDE’s, such as the religious conviction of people, the medications they used prior to the cardiac arrest, or the duration of the cardiac arrest, could all be refuted. This was done by means of cross-tabulations with the (nature of) experiences and additional information on the participants recorded prior to the cardiac arrest.
So, none of the commonly addressed alternative explanations hold. This conclusion is extrapolated to the supposed location our consciousness, which supposedly cannot be in our brain (according to the Lancet-article), and subsequently extrapolated to the existence of an afterlife (in his book). True crucial argument proposed by Van Lommel is that this is necessarily so, and not due to distorted brain functioning, because we know that during cardiac arrest the human blood pressure is too low to sustain brain functions and thereby consciousness. Thereby, the linchpin of his argument is the accuracy of the measurements on brain activity during cardiac arrest.
Although in general I do have confidence in the instruments measuring brain activity, after reading an article in a non-peer reviewed journal (Natuurwetenschap en Techniek, written in Dutch by Niki Korteweg) I recently lost my confidence in these instruments for this purpose. These measurements only give an indication of the combined pulsing of brain-cells. But there are indications that, when deprived of enough oxygen, brain cells tend to pulse randomly. That is not picked up by the measurements Van Lommel refers to. It is unknown whether or not this leads to some form of consciousness, and thereby cannot be ruled out.
Additionally, the argument that during cardiac arrest blood pressure is too low to sustain consciousness is crucial to Van Lommels statement that consciousness cannot emerge from brain-activity during cardiac arrest. However, this only holds for people in average. So, the average blood pressure is too low to sustain consciousness. However, an average comes with a standard deviation, which learns us that about 20% of the people have a blood pressure high enough to sustain some kind of consciousness, even without a heartbeat. To me, this percentage is very close to the percentage of people that had a near death experience (18%) in the Van Lommel study. So, their near death experience (I do not contest the experience they had, only its origin) is not an outside-body experience, but a result of a physical brain that basically functions but is distorted by shortage of oxygen.
There is much more to be said regarding the existence of an afterlife. However, in this case of scientific inference on this subject, I cannot but conclude that the measurement issues form an alternative explanation on near death experiences that is much more likely than the existence of an afterlife. To me, this is another example of what I recently wrote on the importance to reflect on the uncertainty that is associated with research methods, instead of building castles on loose sand.
VANLOMMEL, P., VANWEES, R., MEYERS, V., ELFFERICH, I. (2001). Near-death experience in survivors of cardiac arrest: a prospective study in the Netherlands. The Lancet, 358(9298), 2039-2045. DOI: 10.1016/S0140-6736(01)07100-8