What does it mean to say that one is "bullish" on gold? Or "bearish"? Or, more simply, what is a bull or a bear?

"A bull is an investor who thinks the market, a specific security or an industry is poised to rise. Investors who adopt a bull approach purchase securities under the assumption that they can sell them later at a higher price. Bulls are optimistic investors who are attempting to profit from the upward movement of stocks, with certain strategies suited to that theory. ...James Chen, Investopedia

According to the definition, then, being bullish on gold is an indication that an investor can optimistically purchase gold and expect to sell it later at a higher price for a profit. 

"A bear is an investor who believes that a particular security, or the broader market is headed downward and may attempt to profit from a decline in stock prices. Bears are typically pessimistic about the state of a given market or underlying economy."...James Chen, Investopedia

As contrasted, then, with being bullish on gold, being bearish implies that an investor is pessimistic if he thinks that gold prices are headed lower, "and may attempt to profit from a decline" in prices.

From the same source quoted above:

"A bull investor believes that the market will increase in value over time. Bears are the opposite of bulls and they believe that the general direction of prices in a market trends towards a decline." 

So, which is it; price or value?

We place a value on things by setting a price for them. A new dress, a haircut, our homes, stocks, etc., all have a perceived value that is measured by the price affixed to it.

The price of a specific item or asset at any given time is a reflection of varied opinions. Some are based on fundamentals, some are based on technical factors. But the combination of all the opinions, and the resulting expectations (some expect the price to go up, others expect it to go down or remain the same), plus all of the other known factors at the time that might possibly impact the price, provide us with the clearest possible indication of current value for the item in question: its market price.

So why does the price of gold change; and what is the value of gold?

Gold is the original measure of value for all other goods and services. The US dollar is a substitute for gold.

Hence, gold's increasing price is a reflection of changes (losses) in the purchasing power of the U.S. dollar. Gold's value is in its use as money; and its value is constant and stable.

Since the US dollar is in a state of continual deterioration, the price of gold continues to rise reflecting inversely that same US dollar deterioration.

In other words, while the price of gold continues to rise over time for the reason stated above, its value is unchanged.

(Note: There are periods of time during which the US dollar exhibits strength and stability to a degree that is reflected in a lower gold price. We are in one of those periods now and have been since 2011. Significant temporary volatility and erosion of the gold price can wreak havoc on those who consider themselves long-term investors.)

Not a few gold bulls are of the opinion that much higher prices for gold are in the offing sooner rather than later. There is also the expectation that the much higher prices will be hugely profitable to gold investors.

However, the price for gold can only go higher if there are further significant declines in the US dollar. As such it would represent a clear turnaround in the current trend of US dollar strength. At this time, that does not appear to be happening.

Also, gold above $1500 is fully-priced. At $1700, gold is only ten percent below its high in August 2011. But it is sixty-five percent above its low in December 2015. That represents a better than six-to-one risk/reward ratio. I would rather have those odds reversed and in my favor; not against me.

Finally, if you are bullish on higher gold prices, then you are, by definition, bearish on the US dollar.