How does one verify evidence? The process of scientific thinking is the method that is used for doing this. The factors that constitute this method are: Observation, Logic, Inference and Verification (this is of three types, viz., direct, repeated and universal), followed by experiment. What comes out of this is the scientific outlook. All the discoveries made so far are the result of some observation. We are taught in school about steam energy discovered by James Watt. The story goes thus. James Watt was engrossed in his thought. A kettle was boiling by his side. When enough steam gathered in the kettle its lid fell off. James put the lid back on the kettle. It fell off again after a little while. A few repetitions set him thinking about the reason for the lid coming off. He did not imagine a ghost in the kettle. He reasoned that since the lid comes off again and again, there must be something inside that pushes it out. This reasoning resulted in the discovery of energy contained in the steam, which led to the industrial revolution in Europe. Another example: we celebrate 28th February as National Science Day, because C.V. Raman’s discovery of ‘Raman effect’ was published in world-renowned magazine ‘Nature’. Later he won the Nobel Prize for it. How did he discover it? He was going to England in a liner. Every day he used to go to the deck and see the deep blue sky above and the deep blue sea below. He was curious to know why. Now he could have praised God for creating the beautiful blue sky above and the beautiful sea below. But, he did not do that. He started reasoning and discovered a novel scientific truth. Thus, scientific outlook starts from observing phenomena and asking oneself the question ‘why’.
Now one cannot expect to prove everything by observation. Suppose you have lost your way in a jungle in the evening. You need to reach some small settlement before night. Since you do not know where such a cluster of hutments can be found, you would not know which way to go. Then if you see some smoke going up at a dozen places by the side of a hill, you think this may be an indication of a settlement and you take the path towards it. What is the basis of your choice? You have not seen any men or a settlement or their fireplaces. But you know that wherever firewood is used for cooking, there is smoke and in the jungle, firewood is used for cooking. Evening is the time for cooking dinner and if food is being cooked in every hutment, there would be a dozen places from where the smoke can rise. So you deduce that there must be people living there and they are preparing their dinner. On the basis of this logic you proceed in that direction and your deduction turns out to be correct. Scientific outlook consists of firstly observation, secondly reasoning (or logic) where observation is not possible and thirdly inference. Let me explain the third constituent, inference. A friend of yours, who is a late riser, suggests that you accompany him for a walk at sunrise next morning. He promises to come to your house very early next day. Since you know he is incapable of doing this, would you argue with him, ‘Oh, you want to go for a walk at sunrise, but how are you sure that the Sun will rise tomorrow?’ No you won’t. But how does one know that the Sun is going to rise tomorrow? When we give appointments several days in advance, how do we know that those days are going to break on this earth? We deduce this from our knowledge that the Sun has been rising regularly in the morning for the last 460 crore years. It has not taken any leave at all. If it does that even for a day, it can cause a permanent “leave” for all the living things on earth. Since the Sun has been rising regularly so far, you infer that it will do so even tomorrow and plan to go for a walk in the morning. This is inference.
The next factor is verification. We have already seen that it consists of three parts: verification, repeated verification and universal verification. What is verification? Adi Shankaracharya had said, even if hundred wise men tell you that fire is cool, will you believe it? No, you will not. If those hundred wise men say, ‘not only do we say it, but it is also written in the book’, you would reply, ‘I do have a lot of respect for all of you but the direct evidence, my own experience, tells me that if I put my hand in fire it will burn.’ Verification by direct experience is an important part of scientific outlook. Now we will see what is repeated experience. Someone tells you that using a certain enchanted ring will secure employment for the user within one month. You ask him to give you proof. He then says that he had used it and later his neighbor had used it and both got jobs within a month. What you should argue with him, is that if the same experience is repeated a large number of times, then we should make ten thousand such rings and distribute them among ten thousand unemployed youth. If they all get jobs within a month then we can accept that this ring does have some supernatural power of securing jobs for the unemployed. We cannot draw conclusions from just one or two examples. For drawing conclusions you need a very large number of such examples. This is the crux of the scientific outlook. Again this experience or verification has to be universal. It cannot be science without being universal. If you say that only the residents of that particular city will get jobs on using the ring, it will not be acceptable as scientific truth. If the ring really is capable of getting a job for the user, any body anywhere should get a job within a month on using it. If a medicine is developed for a particular disease, it will cure any person suffering from that disease any where in the world. When the law of gravitation was proved, it could be applied anywhere in the world to verify it. Thus scientific outlook is founded on direct verification that is repeated in very large number and is universally applicable.
Experiment is the last important constituent of scientific outlook. Anybody should be able to verify scientific truths by conducting required experiments. Water boils at 100 degrees centigrade. It means that water will boil at this temperature anywhere in the world, be it Bombay, Calcutta, London or Madras. If it boils at a lower or higher temperature at any place, you have another universal law that explains why and to what extent the boiling point of water rises or drops. It is not that water will boil at 90 degree centigrade in Mumbai and save fuel because the residents of Mumbai are very religious, while the residents of Moscow being atheist water boils there at 110degrees centigrade. One can verify it by experiment. So observation, the question ‘why so’ based on the observation, then reasoning or logic where observation is not possible, followed by inference and verification and lastly experiment are the steps that build the scientific outlook. There is a lot of value content too in the scientific outlook. It tells how a human being should look at life in general. The value content dwells in the method of scientific thinking.