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Why Do We Need Science?

Humans are poor data gathering machines. We have numerous biases, cognitive flaws, and psychological errors that prevent our unguided minds from grasping reality in any accurate way.

To put it more specifically:

[There are] two countervailing human tendencies of omission and commission: to neglect the logical and statistical strategies of science on the one hand, and to over-utilize intuitive or simplistic strategies on the other

Thus, in order to deal with the deluge of information that our brains take in every second of everyday, we have to structure it in a way that can accurately interpret, explain, and predict reality. Science can do this where other forms of thinking fail. Gut-feelings and common sense are not enough; they may get us somewhere, but not always to the truth.

As we proceed, I will outline how one thinks scientifically (and unscientifically) in order to show you how modern science obtains knowledge about the universe. More importantly, as we continue, we should know why thinking in a scientific way is the best vehicle for obtaining knowledge.

To that end, let us outline what are the unscientific ways of thinking and why we cannot rely on them.

Unscientific Sources of Knowledge


By intuition we mean vague feelings or gut reactions about a question or phenomena. One problem with intuition as a knowledge source is that our intuitions are often wrong. For example, we may have a gut reaction that giving children sugar will make them more hyperactive. However, if we scientifically interpret the data, we find that this is not that case.

A second problem arises because intuitions are feeling-based. Mood, and a host of other psychological and physiological factors influence intuition. A judgment of information may be solely based on how you rolled out of bed this morning, and not what the data says. An “intuitive” judgment about the driving skills of another motorist will differ greatly if that motorist just cut you off.

Finally, ask five different people to make predictions based on intuition and we are likely to receive five different answers. We simply cannot place enough confidence in intuition to accept it as a source of information.


This second source of unscientific information, know also as tradition, includes unquestioned belief in superstitions, truisms, and myths. These forms of knowledge are often passed from generation to generation through cultural mechanisms such as family, media, and religious institutions. As an information source, tradition is used all the time. Like intuition however, many tenaciously held beliefs are inaccurate.

For example, at one time everyone held tenaciously to the beliefs that the Earth was flat; that the Sun revolved around the Earth; that applying leeches to the ill was good medical practice; and that Salem, Massachusetts was plagued with witches.

Scientific breakthroughs in medicine, physics, and genetics, to name a few disciplines, continually expose the erroneous nature of previously held beliefs. Moreover, across and within cultures there is considerable variance in perspectives: What seems obvious to one social group is often rejected as ludicrous by another.

Tenacity, like intuition, is an unacceptable way to answer scientific questions.


Common sense, a third unscientific way of knowing, consists of generating what appear to be obvious answers to scientific questions. Appeals to this sort of knowledge are accompanied by prefacing or supporting remarks such as “it’s obvious that…,” “everybody knows…,” “any halfway intelligent person can see that…,” or “it’s just common sense.”

Common sense, however, is often wrong and people often disagree what even constitutes the common sense thing to do in a particular situation. Furthermore, scientific problems abound for which common sense provides no insight. This is especially true for complex problems.

For example, what is the commonsense way to search for the Higgs Boson? What is the commonsense way to treat pancreatic cancer? There are no existing commonsense answers to such questions.


Personal experience is often used as a knowledge source. We posses a wealth of personal experience and, while experience is an extremely valuable resource, there are three reasons to be cautious about deriving knowledge claims about science based on experiences.

First, personal experience is both subjective and uncontrolled, leaving us susceptible to misperception and misrepresentation of events. We are limited in the amount of information we can process because the quantity of stimuli in any given situation is virtually unlimited. Because of this limitation, we often attend to events and stimuli selectively: We simply do not and can not pay attention to every sound; we don’t notice everything there is to see; many things go undetected. Rather, we attend to some stimuli and block out others, some of what we do sense, we sense incorrectly, yielding an experience that is necessarily incomplete and inaccurate.

Second, we selectively remember characteristics of experience. Anyone who has every studied for a test realizes that some of the subject matter, although we read it and perhaps even hear it during class, was somehow lost on test day. Thus, our memories of events are usually incomplete and misrepresent events. It is also problematic that our selectivity is driven by strong preconceptions. Meaning we attend, perceive, accept, and recall data that confirm our beliefs and attitudes whereas we tend to ignore, distort, discount, and forget data which disconfirm our beliefs and attitudes. This is the confirmation bias at work.


A fifth unscientific source of knowledge, authority, consists of appealing to experts for answers to our questions. We are surrounded by experts and authorities: professors, physicians, attorneys, journalists, economic advisers, stock brokers, mechanics, news anchors, just to name a few. Although experts frequently provide valuable service, there is often disagreement among them, and, of course, they can be wrong.

The more important issue is how the experts gained their knowledge in the first place. If their knowledge was acquired through intuition, tenacity, or experience, it is subject to many of the caveats already mentioned.

Assuming that an expert’s knowledge is the product of scientific inquiry, it is the scientific inquiry, not the expert, that is the source of the knowledge. Well-informed experts can disseminate knowledge but they are not acceptable as oracles of it.


A final unscientific of deriving answers is through rationalism, or logic, usually in the form of deduction. Accordingly, knowledge takes the form of conclusions, which are deduced from premises. For example, suppose that (1) watching a scary movie usually makes a person fearful or anxious, and that (2) being fearful or anxious usually causes the person’s heart rate to increase. Applying logic we would conclude, therefore, that watching a scary movie raises a person’s heart rate.

Two major problems are associated with rationalism as a source of knowledge. First, we must consider how the truth of the premises were determined. Logic alone cannot produce premises, and without valid premises, sound conclusions cannot be reached. Second if we apply logic in this form to premises that are not absolutely true, erroneous conclusions will be met even when strictly following the rules of deduction.

Reconsider our example. Suppose that when we said “usually” we meant around 70 percent of the time. Thus, the probability of a scary movie making you fearful is 70 percent and the probability of being fearful increasing your heart rate is 70 percent. What then is the probability that watching a scary movie increases your heart rate? The correct answer is calculated by multiplying the two probabilities together ,[.70x.70], which equals only 49 percent. So, more often than not, watching a scary movie would not increase your heart rate, given the probabilities we assumed.

Logic itself does not provide these crucial probabilities estimates; nor does it produce the premises. As humans who are very bad at estimating probabilities, relying on pure logic will not get us as far as science can. While logic is an essential tool used by scientists, it alone is insufficient as a knowledge source because its use requires existing knowledge in the form of premises. If the premises are incorrect, so is your logic.

Thinking Scientifically

As we can see from this brief overview of the unscientific sources of knowledge, we need a more precise and objective approach to generating knowledge. This leads us to the scientific perspective of knowledge acquisition.

Regardless of the field of study, those committed to a scientific approach to generating answers to questions, whether theoretical or practical in nature, can almost always be described in terms of a five-step process known as the scientific method. We will quickly review the steps with special focus on how they differ from unscientific ways of gaining knowledge. The steps are:

  1. Observe a phenomena that needs to be explained
  2. Construct provisional explanations or pose hypotheses
  3. Design an adequate test of the hypotheses
  4. Execute the test
  5. Accept, reject, or modify our hypotheses based on the outcome of our test


The first step describes a basic characteristic of scientific thinking, curiosity. We notice that an object let go on Earth always falls straight down. We see that some planets are made almost entirely of gas. We wonder why some animals take care of their young and others do not. When we focus on such observations and feel compelled to explain them, we have engaged in the first step of the scientific method.


It is at this second step that we begin to differentiate scientific from unscientific thinking. Not having found an explanation for a phenomena, a scientist looks for clues in existing research. Under a scientific framework, input from intuition, tradition, experience, common sense, experts, and logic might be incorporated during the construction of a preliminary hypothesis, but we do not at this point accept the validity of those explanations. These unscientific explanations may be correct, but we cannot be sure if we do not test them.

Scientific thinking builds upon the previous thinking of previous scientists, thus ensuring the maintenance of objectivity separate from unscientific forms of knowing.


Another feature of the scientific method is the testing of hypotheses that take care to control for all of the possible variables that might confuse the research. Scientists must rule out all competing explanations if they are to show that their explanation is the correct one. Unscientific thinking leaves many possible explanations up for debate, and rarely settles on the truth (or tests for the explanation’s validity).

With all of the possible confusing variables controlled for, the scientist carries out the experiment. If the experiment was designed correctly and carried out in the right way, the scientist should receive objective data about the phenomenon in question.

Just how a scientist carries out a “correct” experiment is a much larger subject, and will not be discussed here. Suffice to say that all scientific research depends on scientists following common experimental rules and procedures to make sure that their data can be replicated by others, is falsifiable, and reflects reality.


The final stage of the scientific process calls for the rejection, acceptance, or modification of the explanation based on an analysis of the data. During this process the scientist takes many things into consideration: statistical significance, experimental error, false positives and negatives, etc.

The power of science resides within this final stage. The ability for science to progressively accumulate knowledge that has been checked, tested, repeated, and verified separates it from all other areas of knowing. Science knows when it is wrong and when it has made a mistake, and the internal mechanisms of peer review etc. then move it forward. This is what separates science from pseudoscience. Pseudoscience, like homeopathy for example, does not incorporate new evidence and indeed proceeds without it. Scientific evidence that clearly rejects the idea that homeopathy could ever work is dismissed and forgotten by the proponents of pseudoscience. This sort of thinking, without the checks and balances of science, then becomes an unscientific form of knowledge, and is not reliable.

Science as a Way of Thinking

Science, as a human enterprise, is the most successful tool ever devised for explaining our universe. It has passed the tests that other forms of thinking do not. This is why science proceeds the way that it does, and why it is so powerful.

Adapted from Michael J. Betty’s essay entitled: “Thinking Quantitatively”, published in the book An Integrated Approach to Communication Theory and Research.