copypasta bc I'm feeling lazy
from
http://www.philosophos.com/philosophy_article_145.html
Argument from Analogy
Firstly, the analogy of human created products with the phenomena of the universe is fallacious. Taking complex products as effects of human production is one thing. We observe this every day. We create products ourselves everyday. I can observe a house and without any problem, conclude that human beings — architect, bricklayers and so on — created it. It is safe to conclude a posteriori, on the grounds of observed experience that a house needs the combination of land developers, planning departments, architects and builders without which it would not be built; that human complex contrivances presuppose human design. This conclusion is reached from the experience of such things. It is not safe to extend this a posteriori reasoning to what is unobserved — to the creation of the phenomena of the universe — which the argument from design does.
So upon and within the grounds of observed experience, it is safe to conclude that complex designs of a car, a house, a hammer presuppose human designing intelligence; for it has been observed that the former cannot exist without the latter. It has not been observed of the phenomena in the universe that they cannot exist without a designing intelligence. So, the argument from design is resting on a conclusion extending from an observed premise to an unobserved premise and this does not follow. A premise is fallacious making the conclusion unsound. Applying thinking 'inside the box' of human experience to what is 'outside the box' of human experience, is not conclusively sound.
Secondly, the argument from analogy rests on complex human artefacts requiring a human designer. But it doesn't follow that all human artefacts are complex in character. Some are simple, like the whittled stick or the stone used to make markings. As such, the analogy doesn't hold as human artefacts are not always complex. If not all complex then the example of created human objects as complex being analogous for complex phenomena of the universe doesn't follow.
Thirdly, contrary to its claims, the argument from design does not remain within observed experience. Remaining within a posteriori reasoning alone permits the conclusion only that human designer's create artefacts, products of complexity. Contrary to a posteriori reasoning, its limits are transgressed and something not observed within experience is introduced as the cause of what is empirically observed. This appears to commit the fallacy of Petitio Principi — assuming the truth of that which has yet to be proven.
Like effects prove like causes?
Yet it is retorted that like effects must follow from like causes. We conclude the complex yet coherent innards of a watch are effects of a designing cause. Likewise, the complex yet coherent phenomena of the universe are an effect of a cause — a designing cause. The like effects of complexity arise from like causes. For all complex coherence there must be a designing intelligence. Again, that P leads to Q does not entail Q leading to P. That a designer P leads to designed complexity Q does not logically entail that complexity Q entails a designer P. This is borne out when we observe human designers create artefacts and products of complexity but is not borne out by observing non-human phenomena and inferring they likewise require a designer. It can be concluded only that human designing intelligences entail complex, designed artefacts.
So the phenomena of the universe if perceived as complex yet purposive in their manifestation, do not logically or empirically entail an intelligent, designing cause. There may be other explanations and/ or none.
Complexity
Contrary to the a posteriori, empirical based reasoning of the Design argument, complexity and purposiveness might be perceptions reducible to human cognition and not an objective character of the universe.[3] If not objective characteristics of the world 'out there' then a central premise of the argument from design — that the universe displays complexity and coherence — is not sound and the desired conclusion of a creative intelligence of such complexity etc. will not follow. Additionally, what is understood by purposive and coherent is problematic. Socrates keeps what appears to be a shambles of a filing system compared to Immanuel whose files are labelled and appropriately placed under definite categories and cabinet draws. Yet Socrates knows were everything is and can retrieve requested information as quickly as Immanuel. So complexity and purposiveness display an ambiguity. With the ambiguity no sure inference can be drawn from complexity to a creative intelligence.
I will now assume that the universe does display a complex coherence of means to ends. Assuming there is an objective complexity 'out there' independent of human cognition where means cohere into ends. Is complexity alone evidence of the necessity of a designing intelligence? No. For even if there is objective complexity it does not escape the fallacy of analogy objection discussed above. Complexity does not require or necessitate a designing intelligence. It just doesn't follow that non-human complexity must require a designing intelligence for its existence.
Even if it were admitted that the complex coherence displayed by phenomena could be accounted for by intelligent design, then the nature of intelligent design itself would have to be accounted for. The agency of intelligent design must itself possess complexity in order to create complexity. If as the argument for intelligent design maintains that complexity has to be explained by an intelligent designer then the complexity of the designer likewise has to be explained. If not, it is being maintained that the intelligent designer does not possess complexity. If not complex it has no understanding of complexity so cannot intentionally design complex creations. So if it designs complex creations, it must possess complexity and this has to be explained in terms of the design argument, in the existence of an intelligent designer of the intelligent designer and so on ad infinitum.
Goldilocks and Intelligent Design
Another approach in the argument for intelligent design is to propose that the conditions for life to exist are so delicate, so intricate that they could not have occurred by chance alone. Neutrons are slightly heavier than protons. If it were the other way round, atoms could not exist, as they would have decayed into neutrons after the 'Big Bang'. No protons, no atomic nucleuses and no atoms. No atoms then no chemistry. No chemistry then no life. That there is life at all is due to the condition of slightly heavier neutrons. In the story of Goldilocks where unlike Father and Mother Bear's porridge, Baby Bear's porridge, is 'just right' — so the conditions in the universe are 'just right': just right to allow life to exist, This so-called 'Goldilocks enigma' cannot have arisen from chance.[4] If not from chance then there must have been a creative intelligence designing the phenomena of the universe.
The immediate response to the Goldilocks enigma is that it is precisely because such delicate conditions pertain that life exists. Without these delicate conditions, life could not exist — as we perceive in the solar system. We are the lucky strike in the cosmic game of dice — no god or deliberate design is necessary.
Furthermore, an intelligent designer could not have been that intelligent. If it had, it would have loosened up on the conditions necessary for life so that they weren't so stringent. Such conditions for life reduce the chances of life rather than necessitate it. A change of a few degrees in temperature can decide the existence or not of life. An intelligent designer would have made conditions more flexible ensuring greater survival conditions for life.
Conclusion
The argument from Design whether to the Abrahamic God or to an Intelligent Designer fails. It primarily fails because it is based on analogous reasoning which is fallacious. Whilst human beings create complex products it does not follow that a designing intelligence is required to create the universe. This undermines the Argument from Design and its modern derivative of arguments for Intelligent Design.