Perspectives on the Natural Sciences

"Certainly, we do know that high-level movement goals and attention-related signals are represented in the premotor areas and that the spread of these signals to the primary motor cortex, possibly already primed by afferent information about limb posture, will somehow trigger the retrieval of motor memories and, subsequently, the formation of a signal to the spinal cord. But the detail of this complicated process, which critically involves coordinate and variable transformations from spatial movement goals to muscle activations, needs to be elaborated further. Phrased more fancifully, we have some idea as to the intricate design of the puppet and the puppet strings, but we lack insight into the mind of the puppeteer."

- E. Bizzi and R. Ajemian, "A Hard Scientific Quest: Understanding Voluntary Movements", Dædalus 2015 (Link)


"That cognitive reach has limits is not only a truism, but also a fortunate one: if there were no limits to human intelligence, it would lack internal structure, and would therefore have no scope: we could achieve nothing by inquiry. [...] We might think of the natural sciences as a kind of chance convergence between our cognitive capacities and what is more or less true of the natural world. There is no reason to believe that humans can solve every problem they pose or even that they can formulate the right questions; they may simply lack the conceptual tools, just as rats cannot deal with a prime number maze."

- N. Chomsky, "The Mysteries of Nature: How Deeply Hidden?", J. Phil. 2009 (Link)


"Einstein commented that, 'It is the theory that determines what we can observe,' and Heisenberg noted that 'We have to remember that what we observe is not nature in itself, but nature exposed to our method of questioning.'"

- G. M. Bodner, "Constructivism: A Theory of Knowledge", J. Chem. Educ. 1986 (Link)


"It's difficult to be rigorous about whether a machine really 'knows', 'thinks', etc., because we're hard put to define these things. We understand human mental processes only slightly better than a fish understands swimming."

- J. McCarthy, "The Little Thoughts of Thinking Machines", Psych. Today 1983 (Link)


"Certain scholars considered that since the appearances on our scale were finally the only important ones for us, there was no point in seeking what might exist in an inaccessible domain. I find it very difficult to understand this point of view since what is inaccessible today may become accessible tomorrow (as has happened by the invention of the microscope), and also because coherent assumptions on what is still invisible may increase our understanding of the visible."

- J. B. Perrin, "Discontinuous Structure of Matter", Nobel Lecture 1926 (Link)


"An enigma presents itself which in all ages has agitated inquiring minds. How can it be that mathematics, being after all a product of human thought which is independent of experience, is so admirably appropriate to the objects of reality? Is human reason, then, without experience, merely by taking thought, able to fathom the properties of real things. In my opinion the answer to this question is, briefly, this: As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality."

- A. Einstein, Sidelights on Relativity 1922 (Link)


"Hence we may discover the reason why no philosopher, who is rational and modest, has ever pretended to assign the ultimate cause of any natural operation, or to show distinctly the action of that power, which produces any single effect in the universe. It is confessed, that the utmost effort of human reason is to reduce the principles, productive of natural phenomena, to a greater simplicity, and to resolve the many particular effects into a few general causes, by means of reasonings from analogy, experience, and observation. But as to the causes of these general causes, we should in vain attempt their discovery; nor shall we ever be able to satisfy ourselves, by any particular explication of them. These ultimate springs and principles are totally shut up from human curiosity and enquiry. Elasticity, gravity, cohesion of parts, communication of motion by impulse; these are probably the ultimate causes and principles which we shall ever discover in nature; and we may esteem ourselves sufficiently happy, if, by accurate enquiry and reasoning, we can trace up the particular phenomena to, or near to, these general principles. The most perfect philosophy of the natural kind only staves off our ignorance a little longer: as perhaps the most perfect philosophy of the moral or metaphysical kind serves only to discover larger portions of it. Thus the observation of human blindness and weakness is the result of all philosophy, and meets us at every turn, in spite of our endeavours to elude or avoid it."

- D. Hume, An Enquiry Concerning Human Understanding (Section IV) 1748 (Link)


"Since Philosophy is to know all things as they are and to fulfil functions as one should, therefore it is divided with regard to the divisions of existent things, according to those divisions. These are two: that, the existence of which is not determined by the voluntary movements of human persons; and that, the existence of which is dependent upon the control and regulation of this class. Accordingly, knowledge of existent things is also in two divisions: that relating to the first division, called Speculative Philosophy; and that of the second division, called Practical Philosophy. Speculative Philosophy itself is in two divisions: a knowledge of that, the existence of which is not conditional on involvement with matter; and, secondly, a knowledge of that which cannot exist so long as there be no involvement with matter. This latter division is also twice divided: on the one hand is that, into the intellection and conception of which consideration of involvement with matter does not enter as a condition; on the other, is that which is known only by consideration of involvement with matter. Thus, in this way, there are three divisions of Speculative Philosophy: the first is called Metaphysics, the second Mathematics, and the third Natural Science."

- Nasir ad-Din Tusi, The Nasirean Ethics (Akhlaq-i Nasiri) 1235; translated by G. M. Wickens (1964) (Link)