A depiction of abiogenesis, namely the hypothesis (Thomas Huxley, 1870) that by heating and or adding energy to non-living matter, life can be generated, i.e. a frog will eventually hop out of the primordial soup; the logic of which many, in modern times, adhere to via a combination of the Miller-Urey experiment (1952), the RNA world hypothesis (Walter Gilbert, 1986) (Ѻ), the hydrothermal vent theory (Gunter Wachtershauser, 1990) (Ѻ), among other arguments.

“But though I cannot express this conviction of mine too strongly, I must carefully guard myself against the supposition that I intend to suggest that no such thing as abiogenesis has ever taken place in the past, or ever will take place in the future. With organic chemistry, molecular physics and physiology yet in their infancy, and every day making prodigious strides, I think it would be the height of presumption for any man to say that the conditions under which matter assumes the properties we call ‘vital’ may not, someday, be artificially brought together. All I fear justified in affirming is that I see no reason for affirming that the feat has been performed yet. And looking back through the prodigious vista of the past, I find no record of the commencement of life, and, therefore, I am devoid of any means of forming a definite conclusion as to the conditions of its appearance. Belief, in the scientific sense of the word, is a serious matter, and needs strong foundations. To say, therefore, in the admitted absence of evidence, that I have any belief as to the mode in which the existing forms of life have originated, would be using words in a wrong sense. But expectation is permissible where belief is not; and if it were given me to look beyond the abyss of geologically recorded time to the still more remote period when the earth was passing through physical and dynamical conditions, which it can no more see again than a man can recall his infancy, I should expect to be a witness of the evolution of living protoplasm from non-living matter. That is the expectation to which analogical reasoning leads me; but I beg you once more to recollect that I have no right to call my opinion anything but an act of philosophical faith.”

— Thomas Huxley (1870), BAAS president’s address, Sep 14 [2]

“Of the causes which have led to the origination of living matter, it may be said that we know absolutely nothing, . . . Science has no means to form an opinion on the commencement of life; we can only make conjectures without any scientific value.”

— Thomas Huxley (c.1877); in: “Biology”, Encyclopedia Britannia (1780) [3]

“A deep abyss deep abyss separates the inorganic from the organic, the inanimate from the animate. The rock-crystal on the one side, vegetable and animal on the other, how infinitely different the image.”

— Heinrich Frey (c.1877) (Ѻ)

“To say that even the very lowest form of life, not to speak of the higher forms, still less of volition and consciousness, can be fully explained on physical principles alone, . . . is simply unscientific. There is absolutely nothing known in physical science which can lend the slightest support to such an idea. To suppose that life, even in its lowest form, is wholly material, involves either a denial of the truth of Newton's laws of motion, or an erroneous use of the term 'matter.' Both are alike unscientific.”

— Peter Tait (1878) [4]

“A mass of living protoplasm is simply a molecular machine of great complexity, a total results of the working of which, or its vital phenomena, depend, on the one hand upon its construction, and, on the other, upon the energy supplied to it; and to speak of vitality as anything but the name of a series of operations, is as if one should talk of the ‘horologtity’ of a clock.”

— Thomas Huxley (1880), “Biology”, Encyclopedia Britannica (Ѻ)

“Believing, as I do, in the continuity of nature, I cannot stop abruptly where our microscopes cease to be of use. Here the vision of the mind authoritatively supplements the vision of the eye. By a necessity engendered and justified by science I cross the boundary of the experimental evidence. If you ask me whether there exists the least evidence to prove that any form of life can be developed out of matter, without demonstrable antecedent life, . . . [men of science] will frankly admit their inability to point to any satisfactory experimental proof that life can be developed, save from demonstrable antecedent life.”

— John Tyndall (c.1880), Belfast Address [5]

“No evidence worth anything has as yet, in my opinion, been advanced in favor of a living being being developed from inorganic matter.”

— Charles Darwin (1882), “Letter to D. Mackintosh” [5]

“It is mere rubbish thinking at present of the origin of life; one might as well think of the origin of matter.”

— Charles Darwin (1883), “Letter to Joseph Hooker”, Feb 28 [5]