There is a particular principle of theoretical physics named (after its author) "Heisenberg's Uncertainty Principle". In a nutshell, this principle states that it is impossible (in the case of some minute particles) to guage both their speed and their location. By measuring their location, one alters the speed at which they move; by noting their speed, one moves them. Some have used this principle, and its natural corollary that not everything about our universe can be known, to argue against the fatalist philosophy that suggests that all events are predetermined on the basis of the universe constituting a closed system of information.
In any case, a German physicist by the name of Schroedinger developed a metaphor for the representation of Heisenberg's idea. The metaphor runs as follows:
Suppose I take a cat, and I place it within a "black box" (so named by virtue of the fact that its contents are either invisible or unknown). Alongside the cat, I place a radioactive atomic nucleus and a canister of poison gas. Should the nucleus decay, a particle will be emitted that will trigger a mechanism within the canister and fill the box with gas. Thus dies the cat. Over the course of one hour, there is a 50% chance that the event occurs.
As Heisenberg's uncertainty principle dictates, I cannot know the state of the cat. So long as the cat is within the box, it has no status as either living or dead; indeed, it exists only as a possible either. In reality, of course, the cat is also endowed with consciousness and so does exist in one form or another, but should we rob the cat of its ability to know whether or not it is alive (queror ergo sum...) then the experiment presents a most curious paradox. The only way to know whether or not the cat is alive or dead is to open the box but, until then, the cat must be considered as both.
I only raise this issue to express my opinion that the expression, "Curiousity killed the cat", has more to do with the curiousity of a German scientist than it does with the activities of an inquisitive feline.