Wednesday, September 14, 2011

DUE SEPTEMBER 21, 2011 - Why should biologists care about Heisenberg's Principle of Uncertainty? A discussion about what is life

During these first 3 weeks of class, you have quantitatively measured populations of insects, volumes of liquids and solids, sizes of objects (lengths and widths), masses of solids, and temperatures as well as collected qualitative data on insect behavior. At all points, you have encountered limitations that will be discussed in your lab reports and analyzed with statistical tools that will give an approximate measure to the error of your measurements (range and size of your sample). 

During lecture time, we have discussed the nature of the atom and the concept of uncertainty has been introduced. 

Read the three paragraphs below, and discuss within the context of your experiments' results.

In the Stanford's Encyclopedia of Philosophy, Hilgevoord and Uffink discuss Heisenberg's principle of uncertainty under item 2.2, which reads:

"He (Heisenberg) adopted an operational assumption: terms like ‘the position of a particle’ have meaning only if one specifies a suitable experiment by which ‘the position of a particle’ can be measured. We will call this assumption the ‘measurement=meaning principle’. In general ... experiments are never completely accurate. We should be prepared to accept, therefore, that in general the meaning of these quantities is also determined only up to some characteristic inaccuracy.
As an example, he considered the measurement of the position of an electron by a microscope. The accuracy of such a measurement is limited by the wave length of the light illuminating the electron. Thus, it is possible, in principle, to make such a position measurement as accurate as one wishes, by using light of a very short wave length, e.g., γ-rays. But for γ-rays, the Compton effect cannot be ignored: the interaction of the electron and the illuminating light should then be considered as a collision of at least one photon with the electron. In such a collision, the electron suffers a recoil which disturbs its momentum. Moreover, the shorter the wave length, the larger is this change in momentum. Thus, at the moment when the position of the particle is accurately known, Heisenberg argued, its momentum cannot be accurately known:
At the instant of time when the position is determined, that is, at the instant when the photon is scattered by the electron, the electron undergoes a discontinuous change in momentum. This change is the greater the smaller the wavelength of the light employed, i.e., the more exact the determination of the position. At the instant at which the position of the electron is known, its momentum therefore can be known only up to magnitudes which correspond to that discontinuous change; thus, the more precisely the position is determined, the less precisely the momentum is known, and conversely (Heisenberg, 1927, p. 174-5).
This is the first formulation of the uncertainty principle. In its present form it is an epistemological principle, since it limits what we can know about the electron."

Dr. Murase at the Kyoto Institute of Theoretical Physics, proposes that "there is no clear distinction between subject (endo) and object (exo). As there is no definitely isolated object, the reproducibility principle is mostly violated. We must therefore pay much attention to the transients – or processes – during the past history of life".

Finally, researcher Richard Jorgensen proposes that molecular biology is no different in its lack of determinism than the world of physics. His article states:
"Quantum mechanics, especially in Heisenberg’s uncertainty principle raised fundamental questions that challenged the possibility of precise knowledge of the future: For instance, the number of times per second that atoms in a lump of uranium will undergo radioactive decay is known with precision; however, why and when any particular atom will decay is unpredictable by modern physics.
Similarly, although geneticists can measure mutation frequency in a particular system under specific conditions, the timing of a particular nucleotide substitution (or any other mutational event) is unpredictable. Only the likelihood of the mutation can be known. Thus, from an evolutionary genetic perspective, biology is no more deterministic than is physics, as Tautz (2000) has analyzed in terms of population genetic theory ... 

With the advent of genomics, it is theoretically possible to know with absolute certainty the sequence of a region of chromosome carrying a gene and even the sequence of an entire chromosome. However, as Stadler (1954) noted, it is not trivial to precisely locate a gene, i.e., it cannot “be shown to be delimited from neighboring genes by definite boundaries.” This conclusion follows from Stadler’s definition of the gene: “operationally, the gene can be defined only as the smallest segment of the gene-string that can be shown to be consistently associated with the occurrence of a specific genetic effect.” In modern terms, knowing the complete sequence of a chromosome does not allow us to precisely determine all of the “many interdependent elements of a gene, including all those elements in cis that are necessary for the normal operation of a given gene” that is associated with a specific genetic effect (Jorgensen, 2010). In addition, the expression and selective value of a gene in nature may often be dependent on the environment encountered by the organism, perhaps making it impossible to precisely identify the boundaries of a gene.

Distinct from quantum mechanics, it is also important to recognize the relevance to biology of complexity theory, which has identified another type of uncertainty in physics, resulting from sensitive dependence on initial conditions such that relatively simple Newtonian systems may exhibit unpredictable “chaotic” behaviors due to the impracticality of knowing initial conditions precisely enough.

Similarly, it should be evident that knowing all alternative epigenetic states of a given gene in all environments may be unachievable in any practical sense."


Hilgevoord, Jan and Uffink, Jos, "The Uncertainty Principle", The Stanford Encyclopedia of Philosophy (Spring 2011 Edition), Edward N. Zalta (ed.), URL = . Also available at

Masatoshi Murase. "Endo-Exo Circulation as a Paradigm of Life: Towards a New Synthesis of Eastern Philosophy and Western Science". Prog. Theor. Phys. Supplement No. 173 (2008) pp. 1-10. Available at

Richard A. Jorgensen, "Epigenetics: biology’s quantum mechanics". Frontiers in Plant Science | Plant Genetics and Genomics April 2011, Volume 2, Article 10, 1-4. Available at


  1. Biologists should care about Heisenberg's principle of uncertainty because it suggests that there are things that cannot be determined because it is not humanly possible to do so. It affects all aspects of experimentation involving the interaction of living organisms. This principle applies to all fields of science, including biology. For example, in class we have done several labs. The insect trap lab was a combination of quantitative and qualitative data. We were to apply petroleum to different surfaces as an adhesive so that the bugs can get trapped. We can't account for the ability of every bug getting stuck to the trap because we don't know how big the insect will be or the speed at which they will be flying. Those are the aspects of that experiment that i believe Heisenberg would conceive. This idea of ultimate inaccuracy has caused controversy in the scientific community; because all along we think that we are accurately recording and discovering things with our advanced technology when we aren't. Another example can be pulled from the measuring lab. The limitation reached is the point of error which was .01 for all of the equipment. Another limitation reached, was the fact that each measuring tool could only weigh up to a certain measurement. Through the courses of these experiments, we may come across things of inaccuracy(Heisenberg's Principle of Uncertainty) but it is a part of life that we cannot avoid, we just accommodate.

  2. According to, the uncertainty principle states that, "the position and velocity of a particle cannot both be measured exactly at the same time."

    Biologists should care about Heisenberg's principle of uncertainty because the structure of living cells depends on the structure of each atom and the bonds between them. When studying the cell structure, no one can determine the exact number of atoms in a certain cell. So, the description of the atoms in cells is simplified in order to create the laws of cellular biology.

  3. Kathlyn Larralde HBIO P.2September 18, 2011 at 6:06 PM

    Heisenberg's Principle of Uncertainty suggests the point that not everything is entierlly accurately correct that there are limitations. Their is always that point is which you can not be exact in. This affects everything including the fields of science and life (biology). While collecting quantitative and qualitative data in class during labs limitations have been encountered. During the collection of quantitative data we noticed that the equipment had limitations which cause inaccuracy. The tools used in the measurement lab either would have an inaccuracy of about .01 or could only go up to a certain measurement. Showing Heisenberg's Principle of Uncertainty that the measurement of something can not be 100% accurately determined. During the collection of insects from the can and piece of paper which were both covered in petroleum jelly as an adhesive we noted that part of the surface area had to be eliminated as a part for the insects to stick to, so that the item could either stand or hang. Another problem is that not all insects are attracted to these items and probably might not be able to stick because their weight/size is too great for the petroleum jelly to be an adhesive for said insect. Since we do not know for sure which or how many insects will in fact get trapped by the petroleum jelly. Heisenberg's Principle of Uncertainty can be found in this experiment also because accuracy is not a given and their will always a point in which our technology or findings are partly inaccurate- Heisenberg's Principle of Uncertainty. It is humanly impossible to be 100% accurate with our findings but we keep trying to find a way to be as accurate as we can in life or well as accurate as we think we can be so far.

  4. Donovan Brown P2

    Heisenbers law of uncertainty staes that not everything is accurate and or certain but that there is always a margin of error. Ex While measuring in class we encountered a margin of error of .01. When collecting quantative and qualative data there is always uncertainty that cannot be proved phsically. This is Heisenbergs law of uncertainty.

  5. Natalie Rubio P4
    Heisenbers Law of Uncertainty basically states that not everything is perfect or thought to be perfect, but everthing living and or not has something wrong with it.For example in class while we were measuring different items, basically collecting quantative and qualitive data, we found that most of the electronic or normal scales had an error of .01 which we had to take note of for the final draft of data that we have collected from our three items we chose and measured.His law also states that no matter what, nothing can be 100% perfect regardless of anything anyone tells you.

  6. Heisenberg's law of Uncertainty is important because its saying that everything functions in a different way, sometimes you will get accurate results and sometimes you wont. Sometimes Their is an error, For instance While measuring in class (for a lab) we encountered an error of .01, in other circumstances you might get a different error, for different situations. Anyways, Heisenberg's Principle of Uncertainty also states that its simply impossible to be 100% accurate, you might get a very close accuracy but it will never be 100% accurate.

  7. Heisenberg's law of Uncertainty is important to biologists because it states that in general experimental results are never completely accurate. There will always be variables that are not humanly possible to control. It states that there will be errors since all things function differently. This applies to biology because biologists will need to know that no matter how close they try their results will never be completely accurate. For example, it is not humanly possible to simultaneously define the velocity and position of an electron, and biologists need to accept that.

  8. Heisenberg's law of uncertainty states that the quantitative and qualitative data of an experiment especially biological experiments will not always be absolutely accurate.
    in the bug trap experiment we noticed that it would be very difficult and possibly impossible to trap certain bugs due to certain aspects such as the size/weight, attractants/repellants, etc. of the bug. in the lab where we weighed the same items on different balances we noticed that each balance gave us a small difference in its weight.
    the law basically states that its sometimes impossible to avoid an error in an experiment's data.

  9. Gabriel Casella P7G1September 20, 2011 at 8:00 PM

    Heisenbers law of uncertainty states that not everything is 100% accurate and certain but that there will be always a chance of error in the results. Another part to this principle is that the more accurately one property is measured, the less precisely the other can be controlled, determined, or identified.

    One example of this law in our lab was the .01 margin of error of a triple beam balance when used to measure the mass of objects. Also, one cannot assume that the results for the Armadillidiidae was completely accurate because variations in each individuals and variable errors will cause the results to have a margin of error.

    When pouring the substances in the pad it was impossible to get the exact amount (it is impossible to get the same number of atoms, or the same concentration) and thus a margin of error is inevitable. As such, no results are perfect and “accurate”.

  10. Heisenberg's law of uncertainty says that every experiment thats done can not be 100% accurate. theres always a chance for error. theres also variables that humans just cant control which Heisenberg also states in his law. an example that happened in our biology class is when we were weighing objects in grams every machine we used had either a 0.01 gram of uncertainty or could happen just cause of human error meaning that how can we be one hundred percent sure that an object weighs an exact amount.

  11. The law of uncertainty states that every experiment that is done cannot be exactly correct, in other words, it cannot be 100% accurate. There can always be, and most of the time this is true, an error committed in the experiment. For example, while conducting an experiment in biology we encountered an error of 0.01 in just about every machine we were using. That proves that when you weigh an object, there is no such thing as an exact amount.

  12. Heisenberg's law states that no matter how perfect an experiment may seem there will always be an error. A good example is the experiment with the roly polies. The reason why is because even hough cinnamon is know as a natural insect repelent some polies might be attracted to the cinnamon.

  13. Josette Joseph HBIO P-2September 23, 2011 at 8:12 AM

    Heisenberg's law bisically talk about the uncertainty principle was hard even for scientists to accept at first. After struggling with it, however, Bohr developed complementarity theory. This stated that there was a dual nature to things -- an electron was a wave and a particle, for example -- but we could only perceive one side of that dual nature. A sphere, for instance, has a convex and concave aspect. We can sense the convex from outside the sphere, but from inside it appears completely concave. This theory would affect much more than physics, but other fields of science, as well as art and philosophy.

    Everything has flase examinations and it can't really be accurate. there will be eirrors and it doesn't really matter because not everthing is 100% durable.

    I personally accept his law and is genuinely agreeable with it.


    of "The Uncertainty Principle" are available in the following editions:

    •Fall 2008 (minor correction)
    •Fall 2006 (substantive content change)
    •Winter 2001 (first archived) [author: Hilgevoord, Jan; Uffink, Jos]

    Heisenberg law said that no matter how an experiment looks it is not 100% accurate.For example Heisenberg's paper did not admit any unobservable quantities like the exact position of the electron in an orbit.“I t is impossible to determine simultaneously the position and momentum of an atomic particle.”

  15. Heisenbers law of uncertainty states that not everything is 100% accurate and certain but that there will be always a chance of error in the results. Another part to this principle is that the more accurately one property is measured, the less precisely the other can be controlled, determined, or identified. like one example is the roly poly lab

  16. Jose Balcazar HBIO Per 2October 10, 2011 at 6:26 PM

    Heinsebergs law of uncerntainty states that not everything is 100% accurate. This is because in any experiment an error can occur and also because there are just some variables that are impossible to control. An example is like in the Mass measurement there was an uncertainty or human error of .01 grams

  17. Zachary Mallet Honors Biology Period 4October 13, 2011 at 3:25 PM

    Heinsebergs law of uncertainty states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle. In other words, the more precisely one property is measured, the less precisely the other can be controlled, determined, or known. Therefore nothing can be measured 100% accurate, we encountered that in our own labs. For example with the Units and Measurements, the was a error of about .01g because of the accuracy of the equipment we used. The electronic scale could only measure 200g with out reaching a point of error, in response to the error we where only able to measure certain items with out over exceeding the error or 200g.
    Yet again with the insect behavior there was a problem with the bugs, because just because the bugs where repelled or attracted by the Cinnamon or the mint. That doesn't mean that the bugs will try to walk away from the mint or Cinnamon. You can see in our data there was no trend with the the amount of bugs in each side.