If you traveled the universe looking for the designer and never found him you could not honestly say that you have proven he doesn't exist. Maybe he's just better at Hide-and-Seek than you are.
Natural Theology cannot be falsified so it is an unscientific hypothesis.
Natural Theology is an easy explanation but not a scientific one.
(BUT, as you will see at the end of this lesson, there is an extension of Paley's hypothesis that is testable.)

The Inheritance of Acquired Characteristics is an early evolution theory first published by Jean-Baptiste Lamarck in 1809. Lamarck was a respected scientist and the curator of the Natural History Museum in Paris. Fundamental to the theory of Inheritance of Acquired Characteristics is the idea that modifications acquired during the lifetime of an organism are passed on to its offspring.

Imagine a short-necked ancestor to today's modern giraffe. As the twigs within easy reach were eaten the "pre-giraffes" would stretch to reach the more plentiful food higher up. Lamarck argued that this stretching would add a small amount of extra height to the animal and that the extra height would be passed onto the offspring. Therefore the next generation would have slightly longer necks and be able to forage (eat twigs) higher up in the canopy. As those twigs became scarce the animal would stretch to reach the next highest twigs and that exercise would increase its neck length still further and it would pass that longer neck on to its offspring. And so on and so on through each generation giving rise to today's long-necked giraffes.

Lamarck was very keen to "prove" his hypothesis and collect data to support his ideas. For example, Lamarck noted that the sons of blacksmiths have larger, stronger arms than the sons of weavers. Lamarck said this was explained by the Inheritance of Acquired Characteristics. Blacksmiths exercised their arm muscles as they worked and this caused growth of the muscles. Having acquired larger arm muscles the blacksmiths passed that trait onto their sons. Weavers did very little heavy work with their arms (certainly not as much as blacksmiths) so they failed to develop muscular arms and their sons inherited the same unremarkable arms as their fathers.

Nowadays Lamarck's "evidence" would be given further inspection. Perhaps you already understand where Lamarck's blacksmith data could have lead him astray.
Scientists try to control for other important variables that might affect the outcome of an experiment or which might influence an observation.
Were the families of blacksmiths better fed than those of weavers? Did the sons of blacksmiths help their fathers with the work? Were the members of a blacksmith's family more likely to develop more muscles due to their daily activities? (More so than a family of weavers?)
There may have been other factors influencing Lamarck's observations.

But enough about Lamarck's lack of controls.
Remember, science cannot "prove" anything anyway.
Is Lamarck's hypothesis scientific? Can it be disproven?

You might be surprised to learn that Lamarck's hypothesis is scientific because it can be disproven. And, indeed, it has been disproven by both experimentation and observation.

Before going on to the next page try to think of an experiment that would convince you that the Inheritance of Acquired Characteristics is a false hypothesis.
What experiment(s) would you design and how would you measure their outcome?
Also, try to think of an observation, or series of observations, that would disprove the Inheritance of Acquired Characteristics hypothesis.
Here's a clue - think about what you know about human cultures and ceremonies.

After you've given those two ideas some thought move on to the answers.