Science as an area of knowledge requires evidence and justification. A theory that can’t be logically proven can be easily dismissed therefore in this circumstance Hitchens’ assertion makes absolute sense. Take for instance the theory of gravity stated by Sir Isaac Newton, which essentially posits that nothing can be hanging in mid air on the earth. If a pen falls off a table it must hit the ground, it cannot be floating in mid-air. Even though Newton discovered this theory while seated under an apple tree, he had to prove it with evidence and logic, a process now known as the "law of Universal Gravitation".  Science is a trial and error process but in the past scientists have often found it a lot harder to carry out their research and share it. Galileo Galilei is an example of ascientist who has been imprisoned and killed for voicing out his opinions and sharing hisresearch, which had evidence to it.  He is now considered to be great scientist but during his time he was termed as insane for going against religion and god. Galileo stated and defended the theory of Heliocentrism – All planets revolve around a comparatively stationary sun at the center of the solar system. Such a notion was deemed as going against the Holy Scriptures for which Galileo was rebuked and imprisoned, as he essentially said the earth was not the center of the solar system. In truth he was merely showcasing his research and hypothesis as any other scientist would but the people of the time thought of this as blasphemy. But where was the evidence that god exists? Yet people chose to rebuke Galileo even when he had proof for his theory due to their preconceived notions and ideas instilled by the church, an institution that could not provide scientific evidence to prove that god exists. It is ironic that at the time people refused to accept a theory that was and is true due to an ingrained set of beliefs that could not be similarly proved. Yet his theory in today’s day and age is considered to be true as it has substantial evidence to it thereby stating the fact that perspective and culture and historical times change the acceptance of truth and knowledge.
A particular idiom –"seeing is Believing" – quite intrigues me. First recorded in this form in 1639, it means "only physical or concrete evidence is convincing." When we talk about "seeing is believing" sense perception plays a role and defies science in a way. The literal meaning of eyesight under science reads "a person’s ability to see in visible light" while a general meaning of eyesight says "Visual perception is the ability to understand one’s surroundings by processing information that is present in visible light. The subsequent perception is known as eyesight."
What a person sees with his/her eyes is true because it is happening in front of him/her and he/she is witnessing it but when we return to the definition of eyesight, the words "interpret" and "resulting perception" play a key role. Two people might be seeing the same thing but both of them might perceive it in a different way, a disparate tendency caused by their cultural backgrounds, preconceived notions, and the knowledge that they possess. For example, my granddad and I might be looking at a particular situation, such as, a boy and a girl talking to each other in a rather involved manner. While both of us are seeing the same thing and according to science our eyes are not failing us my granddad might assume the girl and the boy are in a relationship while I would think there’s nothing more than a friendship brewing. This difference of opinion is due to a difference in cultural backgrounds and the knowledge and preconceived notions we possess. My granddad grew up in a conservative India where a boy and a girl were meant to behave a in a particular way in society. They were most likely not allowed to be very open with each other, and at that time those were the social norms that were to be followed, but as time passed, things changed. I grew up in an India which was more open-minded and since there were no such norms in modern India, I assumed they were just friends. What we see with our eyes is undoubtedly true and correct as we are watching things unfold right in front of us showing that evidence and science is proved to be right, but when sense perception comes into play, each person perceives things in a different way and the scientific meaning of eyesight is proved wrong.
The words of Christopher Hitchens stand correct when applied to the concepts of medicine and medical science. You need proof and evidence to make an assertion about medicine. You need to be 100% sure whilst identifying a malady and doctors need to provide the right drugs to cure the disease or the consequences could be grave. The tests the doctors take before prescribing a cure are nothing but proof of whether a particular disease has occurred or not. My grandmother had cancer, but the doctors mistook it for some other disease and treated her for that, which cost my grandmother her life, so evidence is very important when it comes to medicine.
At the same time, alternative medicine disproves Christopher Hitchens’ quote.
According to National Center for Complementary and Alternative Medicine (NCCAM), alternative medicine is hard to define because the field of alternative medicine is extensive and continuously changing. NCCAM defines Alternative Medicine as a group of various medical and health care systems, practices, and products that are not usually considered a part of conventional medicine and doesn’t necessarily needproof. A good example of alternative medicine is placebo – it’s a fabricated medically ineffective treatment for anillness or other medical condition intended to deceive the recipient.
"It has a pejorative implication — that it's not real, that it has no medicinal value," says Dr. Robert Ader, a psychologist at the University of Rochester, New York. While talking about the placebo effect another important word comes up – "believe". The capability of a dummy pill or a simulated treatment to make people feel better, just because they suppose it will is the mind’s ability to alter pain, anxiety and exhaustion. We cannot say and verify that the placebo effect works with everyone and works every time, but there have been many cases in which alternative medicine has worked. For example, the author of the book "The Journey" Brandon Bays had a basketball sized tumor and she decided to heal it without using conventional medicine. She was successful and claims to have uncovered a way to let the body heal spontaneously by accessing cell memories and as of 2012 she is very much alive. There’s no definite evidence to alternative medicine, but it has worked so this particular quote would be apt here- "Absence of proof is not proof of absence". Hitchens’ quote in this case is disproved.
Logical positivism states that every statement can be of two categories: demonstrable by observation(synthetic) or logical statements that are analytic. Analytic statements bear no relevance about the world. Christopher Hitchens by hisassertion has redefined analytic as useless, and implied synthetic to be the way ahead. This I believe is not right.
Bearing no significance about the physical world does not mean useless. We cannot call logic useless, just because it is abstract. For instance, 2+2=5, is wrong, 2+2=4, is right, both of these cannot be proved experimentally. But the first example leads to a logical contradiction, while the second example can be shown in line with an axiom – a statement that is considered to be established. They need to be shown incorrect not dismissed.
I do not entirely agree with the quote, but I cannot dismiss it as it is profound when it comes to a few areas of knowledge such as science but at the same time it bears no relevance to alternative medicine and religion. I’d like to thereforeclassify Hitchens’ quote as "deepity", a term coined by Daniel Dennett. Deepity has dualistic meanings, one that is true but trivial on one level and on another level is profound and something meaningless on the other.
The American Heritage Dictionary of Idioms – By Christine Ammer