An art critic, by ridiculing an artwork, can undermine the pleasure one takes in it; conversely, by lavishing praise upon an artwork, an art critic can render the experience of viewing the artwork more pleasurable.
Evidence
An art critic, by ridiculing an R -causes→ ↓P artwork, can undermine the pleasure one takes in it.
Conversely, by lavishing P -causes→ ↑P praise upon an artwork, an art critic can render the experience of viewing the artwork more pleasurable.
Conclusion
So an artwork’s artistic merit R or P -causes→ ↓M or ↑M can depend not only on the person who creates it but also on those who critically evaluate it.
Evaluate
The argument assumes that ↓P or ↑P -causes→ ↓M or ↑M the amount of pleasure one experiences when viewing an artwork contributes to the artistic merit of the artwork.