A short discussion on Biogenesis

X: I can't believe that anyone would still not believe in evolution!

Z: Well, D is one. Go ask him why.

X: D, you don't believe in evolution? Why?

D: I just find the concept of natural selection really quite hard to believe.

*X and Z proceeds to explain natural selection*

D: Okay, but still, it is a process that theoretically takes millions and millions of years! How can scientists be so sure that the universe has existed for this long? Why can we assume that physical laws that hold true now holds true in the past as well, enabling us to extrapolate our methods into the past?

*Critical Hit*

Personal commentary: From my point of view, I haven't been convinced by D, because I have learnt many physical laws, all of which I implicitly assume are independent of the age of the universe. It would be much harder for me than for D to accept that the universe is much younger than it appears to be. However, I do not know why scientists think that the universe is billions of years old. It had just been a habit to accept the word of scientists and deny all that is contrary to it.

Yet the rigour of science is based on the scientific method, and the scientific method cannot tell us if the universe had physical laws so different in the past that we have been misled from its actual age. However, the scientific method can test many other laws that explain other phenomena, along with the assumptions that make these laws work. While these assumptions may not be the absolutely correct one (since there is always the possibility of there existing an unknown variable in a law), it seems reasonable to assume that we can extend these assumptions to untestable circumstances.

Why so? Well, it is hard to say what is "reasonable". Induction is reasonable on daily life, even if we don't know we are applying it. For example, if a drink stall has served you good coffee twice, it seems reasonable to expect that it would serve you good coffee the third time. In this case, applying similar assumptions to all other physical laws is just using induction on a bigger scale.

From the opposing point of view, however, science has only tested its laws for a particular period of time, and thus has only a very small number of data points regarding how the physical laws are affected by the age of the universe. As such, science still cannot reasonably extrapolate that that physical laws that work now would have worked in the past.

We must concede that scientists are human as well. A coherent set of beliefs supported by a few "axioms" is a nice thing to have, and shaking the foundations of natural philosophy with some metaphysical "what if" is hardy worth the trouble.

"Mr Einstein, maybe E=mc²+Rjc³, just that R happens to be zero?"